Plant Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response

Plant Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Plant Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response Jiaqi Guo, LuKuan Guo, Jing Sun, Xinxin Yan, Xuemei Ge, Lijie Li, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6702808/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The development of sustainable, high-performance elastomer is an emerging field, driven by the growing demand for eco-friendly materials with multifunctional capabilities that can meet complex performance requirements. Cellulose, as the most abundant and renewable bioresource in nature, pose significant challenges for its use in the design and fabrication of stretchable elastomer. The intrinsic characteristic of cellulose, namely, the intermolecular hydrogen bonding between neighboring linear chain of D-glucose units, hinder processability and limit its mechanical flexibility. In this study, we developed a chiral nematic liquid crystal elastomer mainly composed of plant derived hydroxypropyl cellulose (HPC), in which the mechanical and optical properties were precisely tuned by modulating the intermolecular forces within the HPC complexes through salting-induced Hofmeister effect. The obtained composite exhibits vivid structural color arising from the right-handed chiral nematic architecture, while its elasticity is controlled by the cellulose-water interactions through hydrogen bonds. The HPC-based liquid crystal elastomer shows remarkable mechanochromic behavior with the structural color shifting in response to applied force. This dynamic color changes enable real-time monitoring of mechanical stress, with practical applications in rehabilitation training. Besides, owing to the biocompatible and biodegradable nature of HPC, the resulting liquid crystal elastomer can be fully degraded within 30 days in natural environments. The current work introduces an innovative strategy for the design of sustainable, high-performance devices based on cellulose-derived elastomers, highlighting the potential for eco-friendly and multifunctional applications. Physical sciences/Chemistry/Biochemistry/Biopolymers Physical sciences/Materials science/Biomaterials/Bioinspired materials Physical sciences/Nanoscience and technology/Nanoscale materials/Molecular self-assembly Physical sciences/Optics and photonics/Optical materials and structures/Biomaterials/Bioinspired materials Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction Our society has set the course of sustainability to define the next frontier of material science, namely, engineering materials from renewable and eco-conscious feedstocks 1 , 2 , 3 . Among the various types of functional materials, liquid crystal elastomers (LCEs) are a unique class of materials that contain the molecular orientational order of liquid crystal with the stretchiness and durability of elastomer, notable for their remarkable anisotropy and high responsiveness to external stimulus 4 , 5 , 6 . This unique combination of anisotropy and dynamic sensitivity to external cues making LCEs as transformative candidates for the next-generation technologies such as soft robotics 7 , adaptive actuators 8 , biomimetic artificial muscles 9 , and tunable photonic systems 10 , 11 . However, conventional LCE synthesis relies heavily on petrochemical-derived precursors ( e.g. , diacrylates 12 , RM82 13 and RM257 5 ), which pose significant environmental risks due to their toxicity and persistence in ecosystems. Addressing this limitation, the pursuit of biodegradable, bio-sourced LCEs has become a critical priority to reconcile high-performance functionality with ecological sustainability 14 . Cellulose, the most abundant plant-derived biopolymer in nature, is a linear polysaccharide composed of repeating β-(1–4)-linked D-glucose units 15 . Each glucose monomer contains three hydroxyl groups (-OH) at the C2, C3, and C6 positions, which participate in extensive intra- and intermolecular hydrogen bond (H-bond) 16 . This unique molecular architecture underpins cellulose’s hierarchical structure, crystallinity, and remarkable mechanical stability, making it a cornerstone of plant cell walls and a critical resource for sustainable materials development 15 , 17 . Owing to the inherent chirality of its molecular structure, some cellulose derivatives or rod-like nanoparticles can self-assemble into a chiral nematic organization with different handedness, creating vivid structural color that due to the selective reflection of circularly polarized light in the visible range 18 , 19 , 20 21 . For instance, hydroxypropyl cellulose (HPC) is a kind of biocompatible cellulose ether that has been widely used in pharmaceutical and food industries 22 , 23 , 24 . It can be dissolved in water and organic solvents across varying concentrations, displaying both lyotropic and thermotropic phase behavior due to its capacity to self-assemble into right-handed chiral nematic phase 20 , 22 , 24 , 25 . Recently, Chan et al. 26 developed HPC-based 3D-printing inks for creating volumetric objects with tunable structural color, while Barty-King et al. 27 produced self-supporting photonic hydrogels with HPC and gelatin, retaining mechanochromism for responsive materials and colorant-free decoration. These results demonstrate the extraordinary versatility of HPC as the building blocks for the design and fabrication of low-cost and ecofriendly functional photonic materials. Although HPC derived chiral nematic liquid crystals have been extensively studied from the perspective of self-assembly, microfabrication, and photonic sensing, to the best of our knowledge, no attempt has yet been made to develop a chiral nematic LCE with on-demand mechanochromic response. The intrinsic structural characteristics of cellulose make it unsuitable for constructing LCE due to its low stretchability. The glucose rings in cellulose chain impart rigidity to its structure 28 , while the -OH groups within the molecular structure form extensive internal H-bond 16 . These bonds significantly restrict the cellulose chain flexibility 29 and result in poor stretchability of cellulose-based materials 30 . In this work, we employ HPC as the primary raw material to prepare optically tunable liquid crystal complexes with the minor addition of acrylic acid (AA). By adjusting the composition ratio between HPC and AA, the resulting polymer composite display varying structural color due to the manipulation of the chiral nematic HPC helical pitch. After crosslinking the monomers into poly (acrylic acid) (PAA), the chiral nematic LCE is subsequently formed by immersing the HPC-PAA complexes in a sodium solution, which modulates the intermolecular interactions via the Hofmeister effect with either salt-in or salt-out process. The obtained HPC-PAA LCE exhibits exceptional mechanochromic behavior with structural color shifting in response to applied force, implying the changes of helical structure of the liquid crystal matrix. These HPC-derived LCEs, with their outstanding visible light sensing properties, are expected to have broad applications and provide a novel approach for advancing the use of cellulosic materials. Results The preparation of chiral nematic liquid crystalline HPC-PAA composite is illustrated in Fig. 1 a. This process involved the self-co-assembly of HPC with the UV-induced polymerization of AA, facilitated by the crosslinker PEGDA and the photo-initiator LAP. As shown in Fig. 1 b, the obtained composite films exhibit a distinct color transition from blue to red with increasing of AA content, implying the increase of helical pitch of HPC matrix. The peak reflectance wavelength of the HPC-PAA composites shifts progressively with increasing AA concentration, displaying a linear correlation. Specifically, increasing the AA content from 10–15% results in a pronounced redshift of the peak wavelength, from 452 to 770 nm. Figure 1 c presents the circular dichroism (CD) spectra of the HPC-PAA composite, characterized by a strong negative Cotton effect, resulting from the right-handed helical organization of the HPC matrix 31 . Besides, when the sample was observed through a circular polarizer with opposite handedness, the HPC-PAA composite displayed a vivid structural color under a right-handed circular polarizer, whereas it appears transparent when viewed through a left-handed circular polarizer, indicative of the selective reflection of right-handed circularly polarized light from the HPC-PAA system. It is well known that the structural coloration in chiral nematic liquid crystal originates from its well-ordered layered structure, acting as 1D photonic crystal 25 , 32 . As shown in Fig. 1 d, the cross-section SEM image of the HPC-PAA composite (with AA content of 14 wt.%) reveals a periodic layered structure that due to the helical arrangement of HPC. This phenomenon can be attributed to the lyotropic behavior of HPC that form chiral nematic liquid crystal phase above critical concentration and further preserved into solid films 33 . The measured distance between neighboring layers can be termed as half pitch of the chiral nematic film, which is proportional to the reflected wavelength peak 34 . Besides, we also notice that the addition of AA can expand the helical pitch of HPC and stabilize its cholesteric structure via polymerization, thereby shifting the reflection wavelength from blue to red. 33 Owing to the high density of -OH groups within HPC, the HPC-PAA composite exhibit intrinsic inelasticity due to the formation of internal H-bond network. To impart stretchability, it was necessary to disrupt these static H-bonds and introduce dynamic, reversible interactions. As illustrated in Fig. 2 a, the hydrophilic nature of the -OH groups enable efficient interaction with water molecules upon immersion. This interaction disrupts the intermolecular H-bond network, leading to a decrease in both strength and tensile properties (0.01 MPa, 155%, as shown in Fig. 2 b). In recent years, ion-solution immersion has emerged as an effective approach for modulating the mechanical properties of hydrogels, in accordance with the Hofmeister effect 35 , 36 , 37 . Research indicates that cations (e.g., K⁺, Na⁺) enhance polymer hydration by weakening chain interactions through salting-out effects, whereas anions (e.g., SO₄²⁻, CO₃²⁻) disrupt hydration layers, thereby strengthening chain interactions through salting-in effects (Fig. 2 a) 35 . Based on these principles, a range of common anions and cations were employed to investigate the influence of ions on elastomer mechanical properties. As shown in Fig. 2 b, the elastomer obtained by soaking in ions solutions with identical Cl − anions but varying cations showed significant difference in mechanical properties. In specific, the elastomer soaked in Cl − solutions containing Ca 2+ and Na + demonstrate the best performance, with a stress of 0.2 MPa for CaCl 2 and a strain of 720% for NaCl. A detailed comparative analysis of the effects of CaCl 2 and NaCl solutions concentrations on the mechanical properties of elastomers revealed that the optimal comprehensive performance was achieved at a concentration of 1M (Fig. S1 a, b). FTIR analysis shows that the introduction of ions broadens the of -OH stretching peak around 3400 cm − 1 and enhances the carbonyl group absorption peaks at 1630 cm − 1 compared to pure HPC and HPC-PAA composite (Fig. S1 c). These changes can be attribute to the ions’ ability to modulate the intermolecular H-bonds within the polymer chains, thereby altering their arrangement and conformation 38 . To enhance the tensile elongation of the elastomer, Na⁺ was selected as the cation of interest, and the effects of various anions on the elastomer’s mechanical properties were subsequently investigated. As illustrated in Fig. 2 c, the elastomer prepared by soaking in Na 2 SO 4 and NaCl demonstrated nearly comparable tensile strains, ranging from 550 to 700%, but with a notable difference in breaking stress. Specifically, the elastomer soaked in Na 2 SO 4 exhibited a breaking stress of 0.27 MPa, significantly higher than 0.13 MPa observed for NaCl-soaked elastomer. Therefore, the HPC-PAA elastomer prepared with Na 2 SO 4 displayed the superior overall mechanical performance and was selected for further testing. Upon immersion in H₂O and ionic solutions, the -OH groups of HPC formed H-bonds with H₂O, as evidenced by the displacement and broadening of the -OH stretching vibration peak in the FTIR spectrum. The prepared elastomers exhibited a distinct H-bond absorption peak (near 3500 − 3200 cm − 1 ) 25 , which could be deconvoluted into multiple types of H-bonds with varying intensities (Fig. 2 d, e, and Fig. S1 c, d, e). Specifically, split-peak fitting analysis of the H-bonds in the 4000–2500 cm⁻¹ range for elastomers immersed in H₂O revealed two distinct peaks at 3230 cm⁻¹ (strong) and 3410 cm⁻¹ (medium). For elastomers immersed in Na₂SO₄ and NaCl solutions, a shift in peak intensities at 3230 cm⁻¹ and 3410 cm⁻¹ was observed, along with the emergence of a new peak at 3583 cm⁻¹ (Fig. 2 e and Fig. S1 d, e). These observations suggested the formation of weaker H-bonds compared to those in H₂O-immersed elastomers. A similar phenomenon was observed in elastomer prepared in CaCl₂ solution (Fig. S1 e). As illustrated in Fig. 2 f, the ratio of strong to medium H-bonds decreased in elastomers processed with Na 2 SO 4 and NaCl solutions, while an increase in weak H-bonds was observed. This indicates that the elastomer prepared by soaking in solutions containing ions exhibited weaker H-bonds compared to that prepared in H₂O. Furthermore, the H-bonds within the elastomer also exhibited a dynamic and reversible nature. To assess the mechanical elasticity of the HPC-PAA elastomer soaked in Na₂SO₄ solution, cyclic compressive tests were performed over 50 cycles (Fig. S1 f). The elastomer demonstrated an initial tensile strain of 300% and a compressive stress of 0.15 MPa. Although a hysteresis loop appeared in subsequent cycles, the stress-strain curve remained reversible, with the hysteresis area largely unchanged. This suggests that while part of H-bonds was partially disrupted during deformation, their partial reversibility helped maintain material integrity. The variation in H-bonds, as an internal interaction within the elastomer, could be attributed to the infiltration of H 2 O molecules during solution soaking. These molecules affected the binding between neighboring HPC chains, thereby reducing tensile strength and increasing elongation at break. To investigate these interactions at the molecular level, molecular dynamics (MD) simulations were performed to quantify the interaction among H 2 O, HPC, and PAA (Fig. 3 a, b), the relative amount of which could provide insights into the binding energies of various ions with water, and shed light on the molecular mechanisms underlying the observed macroscopic behaviors. As illustrated in Fig. 3 c, the interaction ( E Int ) of the elastomer obtained from NaCl solution (≈ -3300 kcal/mol) and Na₂SO₄ solution (≈ -4200 kcal/mol) was significantly more negative than that of the elastomer obtained from H₂O (≈ -2300 kcal/mol). Furthermore, the absolute value of the E Int of the elastomer processed in aqueous solutions followed the order: H 2 O˂ NaCl˂ Na 2 SO 4 . It is well established that a greater the negative binding energy, with a larger absolute value, corresponds to attraction between group pairs and reflects a relative more stable system. These findings indicate that the HPC-PAA elastomer obtained from Na₂SO₄ solution exhibited the highest stability among all tested aqueous conditions, leading to superior tensile performance (0.27 MPa, 575%). According to Hofmeister theory 35 , kosmotropic anions, such as SO 4 2− , Cl − , are known to strongly hydrated with H 2 O molecules. This hydration reduces the availability of free H 2 O molecules that can interact with polymer chains, thereby disrupting the H-bonds between them. As shown in Fig. 3 d, the formation of solvation water due to ion hydration decreased the proportion of free water molecules available for interaction with HPC. Consequently, elastomers soaked in ions solutions exhibit a reduced disruptive effect on HPC interactions compared to those soaked in pure water. MD simulations revealed that that the ratio of free water to solvation water is lower for Na₂SO₄ (7%) than for NaCl (13%) (Fig. 3 e). While H 2 O imparts deformability to the elastomer under tensile or compressive forces, an excess of water reduces the material’s strength. This difference is consistent with the observed variations in the mechanical behavior of the elastomers. Furthermore, the association of ions with H 2 O molecules in ionic solutions also affects the ability of water molecules to form H-bonds with each other. To further understand how the presence of ions reduces the availability of free water, we investigated the H-bond strengths between H 2 O molecules in both pure water and ions solutions. As shown in Fig. 3 f, the H-bond interaction (E H−bond Int ) energy reveals that pure H 2 O exhibits the most negative and highest absolute value (-647 kcal/mol), indicating the strongest H-bonding. In contrast, the Na₂SO₄ solution exhibits the weakest H-bond interaction energy (-540 kcal/mol). This evidence demonstrates that ions in aqueous solutions can effectively regulate H-bonding in water, thereby modulating the dynamic interaction forces within the elastomer. The HPC-PAA composite (with AA content of 14 wt.%) exhibits a red appearance due to the formation of an ordered helical structure (Fig. 1 d), where the helical pitch is proportional to the wavelength of visible light. Upon transformed into an elastomer by soaking in Na₂SO₄ solution, the material can undergo deformation under external forces (tension or pressure). As illustrated in Fig. 4 a, deformation can reduce the helical pitch, shifting the reflected light to shorter wavelengths and causing the material to transition from red to green and then to blue as deformation increases, thus displaying distinct colors at different deformation levels. Figure 4 b shows that, under compressive deformation, the HPC-PAA elastomer exhibits a gradual color transition from red to blue, with each color appearing vividly. This chromatic response is also observed under tensile deformation (Fig. 4 c). Specifically, when subjected to tensile strains of 200%, 400%, and 600%, the elastomer sequentially transitions from its initial red hue to orange, green, and blue. The correlation between color, deformation, and applied force is of significant interest, prompting a detailed investigation into the quantitative relationships among these variables. A linear relationship has been established between tensile stress, deformation ratio, and the wavelength of reflected light, thereby elucidating the underlying mechanisms of this phenomenon. Specifically, as shown in Fig. 3 d, the elongation ratio L/L 0 increases proportionally from 1 to 6 as tensile stress rises from 0.08 to 0.24 MPa, with the reflection wavelength decreasing from 700 to 450 nm. A similar linear trend is observed under compressive deformation (Fig. 3 g), where the compression ratio L/L 0 increases from 10–60% as the compressive stress rises from 0.1 to 0.8 MPa, and the reflection wavelength decreases correspondingly from 700 to 450 nm. The demonstrated linear correlation between applied force, deformation, and the wavelength of reflected light portends significant potential for future applications of the elastomer. Figure 4 f displays SAXS profiles of the elastomer subjected to varying degrees of mechanical stretching. The patterns illustrate the relationship between scattering intensity ( I ) and the scattering vector ( q ), providing insights into the material’s molecular arrangement and crystalline structure. The SAXS profiles are analyzed using Bragg’s law 34 ,, which inversely relates the diffraction angle θ to the interplanar spacing d , facilitating the analysis of sample morphology across micro to macro scales as q decreases. The power-law model correlates the curve’s slope to the sample’s fractal dimension ( df ), while Guinier’s law links the shoulder region to the radius of gyration ( Rg ). The pre- and post-stretching SAXS patterns are comparable, indicating minimal overall morphological changes despite significant influences on finer structures. In the log( q) range of 0.04 ~ 0.01, df values of 3 ~ 4 suggest complex internal structures and rough surfaces, indicating microscale interactions between HPC and PAA. Values of df between 17 ~ 20 in the log( q ) range of 0.008 ~ 0.005 hint at fine pores or ordered structures, suggesting AA polymerization and HPC self-assembly. For log( q ) values of 0.002 ~ 0.001, df values of 1 ~ 2.5 imply one-dimensional arrangements at larger scales. The obtained long periods of 288.7, 290.6, 296.3, and 292.5 nm for initial and stretched samples (200–600%) indicate that the periodic arrangement of crystalline and amorphous regions remains nearly stable despite stretching. The SAXS patterns demonstrate a morphological transition in the HPC-PAA elastomer from a circular to an elliptical scattering signature upon stretching to 600% (Fig. 4 h). This shape change phenomenon is also observed at lower strains of 200% and 400% (Fig. S3). The transition is attributed to the development of anisotropic structures, molecular chain orientation, and crystal alignment along the stretch direction. Figure 4 g presents the WAXS profiles of the HPC-PAA elastomer under increasing mechanical strains. The initial pattern exhibits two pseudo-Bragg peaks at q 1 = 0.51 A − 1 (2θ = 8°) and q 2 = 1.51 A − 1 (2θ = 20.8°), corresponding to d-spacings of d 1 = 2 π / q 1 = 12.32 Å and d 2 = 2 π / q 2 = 4.16 Å, respectively 39 . The increasing of strain induces the diffraction peaks shifting towards lower q -values. According to Bragg’s law, this shift suggests an increase in lattice constants and interplanar spacing, indicative of structural reorganization under tension. While peak intensities are relatively stable at 200% strain, a significant decrease is observed at 400% and 600% strain, signifying a decrease in crystallinity, likely due to anisotropic deformation, which leads to a diminished volume fraction of ordered crystalline domains. The initial WAXS patterns of the elastomer (Fig. 4 h, bottom row) display two concentric rings, signifying an isotropic structure with randomly oriented crystal domains. Upon stretching, these rings evolve into meridionally oriented arcs, indicating preferential orientation of crystal domains and the development of partially aligned microstructures, as evidenced by the altered scattering intensity in Fig. 4 g. The orientation parameter S , derived from the WAXS patterns, increases from 0.264–4.508% with 600% deformation, reflecting enhanced molecular alignment along the strain direction and a concomitant increase in anisotropy of physical properties. Characterizing the structural dynamics of the HPC-PAA elastomer under mechanical deformation provides essential insights into its functional attributes, which may offer substantial performance and sustainability advantages. These properties make the elastomer a promising candidate for advanced applications that prioritize human health and well-being. Figure 5 a illustrates the elastomer’s self-healing ability after a cut, following immersion in a Na 2 SO 4 solution. The interaction between water molecules and ions in the solution with the -OH of HPC and PAA promotes H-bonds formation, facilitating the reorientation and rejoining of severed polymer chains. This process restores the elastomer’s cohesive properties, as shown by the visual comparison in the accompanying image, where the top row depicts the initial cut state and the bottom row shows the healed state after 60 mins. Figure 5 b further evaluates the mechanical performance of the healed elastomer. The “Original” curve, representing the material’s initial state, shows a tensile strength of 0.26 MPa and a strain of 600%. After 30 mins of healing, there is a noticeable decrease in mechanical strength. However, after 60 mins, the material recovers to a tensile strength of 0.15 MPa (57.7% of the original), while maintaining a strain of 600%, indicating a significant recovery of mechanical integrity over time. Furthermore, HPC-PAA elastomers demonstrate exceptional biocompatibility. As shown in the Fluorescence Microscopy images of viable cells presented in Fig. 5 c, the control group displays a uniform distribution of green fluorescence, indicating viable cells. In contrast, the images for HPC-PAA (NaCl) and HPC-PAA (Na 2 SO 4 ) elastomers reveal a partial red fluorescence, signifying non-viable cells. However, only few of non-viable cells were observed during the experiment, indicating a high degree of cytocompatibility for the elastomer, despite a minor cytotoxic effect compared to the controls. Additional quantification of cell viability, shown in Fig. 5 d, reveals that the cell viability within the experimental groups is approximately 91% for HPC-PAA (NaCl) and 94% for HPC-PAA (Na 2 SO 4 ). These findings support the conclusion that the elastomers exhibit good biocompatibility, making them suitable for potential biological applications. Additionally, the HPC-PAA elastomer, derived from natural resources, exhibits excellent biodegradability. To evaluate its environmental degradability, elastomer samples were placed on an outdoor iron mesh, suspended above the soil. As shown in Fig. 5 e, the HPC-PAA elastomer undergoes environmental degradation. Over a period of 10 to 20 days, the samples progressively reduced in size, indicative of increasing degradation. By day 30, the samples were almost entirely degraded. This observation confirms that the prepared elastomers display exceptional degradability in natural environments. The combination of self-healing, biocompatibility, and biodegradability enhances the performance of the HPC-PAA elastomer, while aligning with sustainable development principles. Together, these multifunctional attributes support the design of sustainable and safe biomedical devices, emphasizing the material’s potential for green development applications. The superior mechanochromic properties of HPC-PAA elastomers make them ideal for human motion detection applications, such as monitoring finger joint movements. As shown in Fig. 6 a, the material exhibits a distinct color changes in response to varying degrees of finger bending (from 0° to > 90°), allowing for visual assessment of finger motion through color variation. Specifically, the color shift is closely correlated with the bending angle. As illustrated in Fig. 6 c, the material reflects red light (≈ 700 nm) when unbent, green light (≈ 580 nm) when bent at 90°, and blue light (≈ 470 nm) when bent to 135°. This precise correlation between color and bending angle underscores the potential of HPC-PAA elastomers for accurate, non-invasive motion sensing. This HPC-based elastomer, characterized by its self-healing and stretch-ability, offers a novel solution for pediatric rehabilitation. As shown in Fig. 6 b, the device’s cyclic stretching action is particularly well-suited for repetitive exercises, a key component in upper limb strength recovery. The elastomer’s color-changing response to stretching presents immediate visual feedback, which simplifies the training process and enhances accessibility for users of all ages. This feature not only provides an intuitive way to track exercise performance, but also engages children through an interactive element, thereby boosting their motivation and adherence to prescribed exercises. Figure 6 f shows that the elastomer’s color transitions from transparent to red upon stretching, then progresses to green and blue. Upon the release of force, the elastomer reverts to its original transparent state, a reversible process that can be repeated. Figure 6 d presents four distinct wavelength peaks at 738, 632, 535, and 447 nm, corresponding to the color progression from transparent to blue during stretching. In contrast, Fig. 6 e shows four peaks at 476, 551, 621, and 717 nm during recovery, from blue back to transparent, indicating the elastomer’s robustness and suitability for applications that require repeated mechanical deformation and visual feedback. Furthermore, the color-changing property of this material has been harnessed for encryption applications, as shown in Fig. 6 g. By precisely controlling the extent of cross-linking within the elastomeric matrix, patterns such as letters (A, C) and motifs (a tree) can be imprinted onto the elastomer surface. Additional examples, including letters (B, D) and a flower motif, are shown in Fig. S4. Under non-stretched conditions, the imprinted patterns remain inconspicuous and difficult to detect. However, upon mechanical stretching, these patterns emerge with striking clarity. Notably, as the elastomer is subjected to tensile forces that induce color shifts towards red and blue-green, the contrast and definition of the patterns are significantly enhanced. This unique characteristic endows the elastomer with superior cryptographic potential, making it a versatile material for secure device applications. Discussion In this study, we successfully developed a novel sustainable based elastomer that utilizes cellulose derivative as the primary material (constituting over 85%) and exhibits precise mechanochromic properties, enabling selective reflection of right-handed circularly polarized light. The composite containing 14% AA exhibits a red color with a helical pitch of 440 ± 72 nm. Fabricated via immersion in a 1 M Na₂SO₄ solution, the elastomer demonstrates excellent mechanical behavior, with a tensile strength of 0.27 MPa, 575% elongation. The Na₂SO₄ ions regulate water molecule penetration, weakening H-bonds between H 2 O molecules, which enhances the material’s tensile strength. A linear relationship was established between external force, deformation ratio, and reflection wavelength, highlighting the material’s sensitivity to mechanical stimuli. The elastomer also exhibits robust self-healing capabilities, recovering over 57% of its original strength and maintaining nearly identical deformation after 60 mins. Additionally, it demonstrates high biocompatibility (cell viability > 90%) and complete degradation within 30 days in a natural outdoor environment. The material’s color-changing properties further enable applications in rehabilitation and pattern encryption, offering a versatile platform for secure devices and exercise guidance. Overall, the HPC-PAA elastomer represents a promising material for sustainable and multifunctional applications. Methods Materials All chemicals were used as received without further purification. Hydroxypropyl cellulose (HPC dry powder, HPC grade: SSL, M W = 40000 g·mol⁻¹, as reported by manufacturer) was purchased from Nippon Soda Co., Ltd. Acrylic acid (AA), poly (ethylene glycol) diacrylate (PEGDA), and lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) were purchased from Shanghai Macklin Biochemical Co., Ltd. Deionized water with resistivity of 18.2 MΩ·cm was prepared by Biosafer water purification system (Biosafer-20AS, China). Mouse L929 fibroblasts cell was supplied by ATCC. Dulbecco’s Modified Eagle Medium (DMEM) and others of the bio-related reagents were purchased from Meilunbio Co., Ltd, Dalian, China. Characterization Polarized optical microscopy (POM) imaging was carried out on Mshot microscope (MP41, China) with images taken by polarizers in a perpendicular arrangement, which allowed identification of the anisotropy of the composites. Images were taken with camera (Sony IMX906, resolution of 50M pixels). UV-vis spectroscopy was performed on an ideaoptic-BSC spectrophotometer (iDH2000-BSC, China). Fourier transform infrared (FTIR) spectra were conducted on VERTEX 80 V infrared spectrometer (Bruker, Germany). FTIR spectroscopy was performed in the range of 400 to 4000 cm − 1 with a spectra resolution of 2 cm − 1 . The mechanical properties of the elastomers were evaluated through tensile and cyclic stretching tests using a Universal Tensile Testing Machine (AGS-X, Shimadzu, Japan). Specimens with a width of 10 mm and a gauge length of 10 mm were stretched at a constant rate of 20 mm/min, and all tests were conducted at room temperature. The cross-section morphologies of the samples were characterized using a high-resolution scanning electron microscope (Regulus 8100, Hitachi, Japan) at an accelerating voltage of 3 kV. Before characterization, the samples were rapidly frozen in liquid nitrogen and cryofractured to expose their internal structure, then mounted on a specimen stage and sputter-coated with a 10-nm gold layer for 100 s to enhance conductivity. Two-dimensional wide-angle X-ray diffraction (2D-WAXD) and small-angle X-ray scattering (SAXS) experiments were conducted on a Xeuss 3.0 Discover diffractometer (Cu Kα, 30 W) using an Eiger 2R-1M detector in transmission mode (sample-to-detector distance: 55-1800 mm), with scattering data analyzed via the power-law model 40 \(\:I\left(q\right)=B\bullet\:{q}^{-df}\) (describing fractal structures) and Guinier’s law model 41 \(\:I\left(q\right)={\alpha\:\bullet\:e}^{-\frac{-{q}^{2}{Rg}^{2}}{3}}\) (applicable to small-particle systems). Molecular dynamics (MD) simulations were conducted using the COMPASSⅢ force field and Forcite module implemented in Materials Studio 2020 package. After energy minimization removing potential bad contact of the simulation box, each system underwent equilibration for 400 ps with periodic boundary conditions applied. Short-range Van der Waals interactions were calculated using an atom-based method, while long-range Coulombic interactions were treated with the Ewald summation technique, applying a cutoff distance of 1.25 Å. The equations of Newton’s motion during MD simulation were integrated with a 1-fs timestep. The temperature was controlled by a Nosé-Hoover thermostat at 298 K and the pressure was regulated using Berendsen barostat at 1 bar with isotropic manner applied. Subsequently, production runs were performed in the NVT ensemble for an additional 400 ps to analyze energy and other properties. Preparation of HPC-PAA based chiral nematic LCE In a typical procedure, 0.6–0.9 ml AA (monomer), 0.168 ml PEGDA (cross-linker) and 8.83 mg LAP (photoinitiator) were mixed with 6 g HPC powder and 3.12 g deionized water, achieving a final HPC concentration of 60 wt%. The mixture was then centrifuged at 8000 rpm for 15 minutes periodically over 3 days to ensure homogeneity, then poured into a mold and covered with a glass substrate. After resting for 10 minutes to facilitate HPC self-assembly, the sample was exposed to 365 nm UV light (468 mW/cm 2 ) for 10 minutes to crosslink and capture the chiral nematic organization. The resulting HPC-PAA hydrogel was subsequently oven-dried at 70°C 42 for 6 hours to yield a structurally stable, optically homogeneous composite. With the HPC concentration fixed, the amounts of AA and PEGDA were varied, with AA comprising 10–15 wt.% of HPC, PEGDA at 20 wt.% of AA, and the amount of deionized water adjusted to maintain the final HPC concentration of 60 wt.% in the mixture. After the fabrication process, the obtained HPC-PAA composite was immersed in 1 M Na 2 SO 4 solution at 70°C for 90 minutes, leading to the formation of LCE. Control experiments can be done by immersing the HPC-PAA composite in either deionized water or NaCl under the same conditions. Biocompatibility Assessment of the LCE The as-prepared biocompatible LCE were fabricated by immersing HPC-PAA composites in 1 M NaCl and Na₂SO₄ solutions, respectively. The elastomers were then sectioned into 20 × 20 mm² specimens and incubated in 2 mL of DMEM at 37°C for 24 hours and the cell viability were determined by CCK8 medium containing 10% fetal bovine serum overnight. L929 fibroblasts cell was seeded in 96-well plates at a density of 10,000 per well and cultured in DMEM medium containing 10% fetal bovine serum overnight. 10 µL of each DMEM sample was added into the plate (experimental groups). 10 µL of fresh DMEM was used as control groups. Six parallel replicates were performed to ensure statistical robustness. Following a 1-hour incubation at 37°C, the solutions were removed, and absorbance was measured at 570 nm using a microplate reader (FilterMax F5, Molecular Devices, Shanghai, China). Cell viability was quantified based on the relative growth rate (RGR): Where \(\:{\text{A}}_{\text{s}}\) , \(\:{\text{A}}_{\text{b}}\) , \(\:{\text{A}}_{\text{c}}\) represent the absorbance values of experimental group, blank group and control group, respectively. To assess cell viability, the cultured cells were aspirated and stained by Calcein and Propidium Iodide. The L929 cell was treated with each group and then incubated with 100 µL medium which contains staining reagent solution in a 96-well plate at 37°C for 30 minutes. Confocal Laser Scanning Microscope (DFC310-FX, Leica Microsystems, Germany) was used to capture and record the results. LCE Self-healing Assessment The as prepared HPC-PAA elastomer, with 20 mm in width, was precisely cut, and the severed surfaces were carefully realigned and brought into contact. Then the attached samples were immersed in a 1 M Na 2 SO 4 solution at 70°C for 30 or 60 minutes to facilitate self-healing. After the designated healing period, the samples were examined for visual integrity and subsequently subjected to further mechanical testing to assess their self-healing performance. Declarations Author Contributions Lukuan Guo, Jing Sun: Data curation, Formal analysis, Methodology, Writing–original draft. Xinxin Yan, Xuemei Ge: Investigation; Methodology. Guang Chu: Conceptualization, Supervision, Writing–Review & Editing. Junlong Song: Writing–Review & Editing. Jiaqi Guo: Conceptualization, Methodology, Project administration, Supervision, Writing–review & editing. Notes The authors declare no competing financial interest. Acknowledgments The authors acknowledge the funding support from National Natural Science Foundation (32371811), Natural Science Foundation of Jiangsu Province for Youth (BK20210622), and Shandong Postdoctoral Science Foundation (SDBX2023039). The authors thank the project of Specially Appointed Professor Plan of Jiangsu Province. References Zheng G , et al. Recent advances in functional utilisation of environmentally friendly and recyclable high-performance green biocomposites: A review. Chinese Chemical Letters 35 , 108817 (2024). Ajdary R, Tardy BL, Mattos BD, Bai L, Rojas OJ. Plant Nanomaterials and Inspiration from Nature: Water Interactions and Hierarchically Structured Hydrogels. Adv Mater 33 , 2001085 (2021). Tang J, Sisler J, Grishkewich N, Tam KC. Functionalization of cellulose nanocrystals for advanced applications. Journal of Colloid and Interface Science 494 , 397-409 (2017). Kularatne RS, Kim H, Boothby JM, Ware TH. Liquid crystal elastomer actuators: Synthesis, alignment, and applications. Journal of Polymer Science Part B: Polymer Physics 55 , 395-411 (2017). Saed MO , et al. Molecularly-Engineered, 4D-Printed Liquid Crystal Elastomer Actuators. Advanced Functional Materials 29 , 1806412 (2019). Zeng H, Wani OM, Wasylczyk P, Kaczmarek R, Priimagi A. Self-Regulating Iris Based on Light-Actuated Liquid Crystal Elastomer. Adv Mater 29 , 1701814 (2017). Wu S, Hong Y, Zhao Y, Yin J, Zhu Y. Caterpillar-inspired soft crawling robot with distributed programmable thermal actuation. Science Advances 9 , eadf8014. Shang Y, Wang J, Ikeda T, Jiang L. Bio-inspired liquid crystal actuator materials. Journal of Materials Chemistry C 7 , 3413-3428 (2019). Kotikian A, Truby RL, Boley JW, White TJ, Lewis JA. 3D Printing of Liquid Crystal Elastomeric Actuators with Spatially Programed Nematic Order. Adv Mater 30 , 1706164 (2018). Wang Y, Liu J, Yang S. Multi-functional liquid crystal elastomer composites. Applied Physics Reviews 9 , 011301 (2022). Guo J , et al. Biodegradable Laser Arrays Self-Assembled from Plant Resources. Adv Mater 32 , 2002332 (2020). Ma J, Yang Y, Valenzuela C, Zhang X, Wang L, Feng W. Mechanochromic, Shape-Programmable and Self-Healable Cholesteric Liquid Crystal Elastomers Enabled by Dynamic Covalent Boronic Ester Bonds. Angewandte Chemie International Edition 61 , e202116219 (2022). Ambulo CP, Burroughs JJ, Boothby JM, Kim H, Shankar MR, Ware TH. Four-dimensional Printing of Liquid Crystal Elastomers. ACS Applied Materials & Interfaces 9 , 37332-37339 (2017). Tang S , et al. Current trends in bio-based elastomer materials. Susmat 2 , 2-33 (2022). Heise K , et al. Nanocellulose: Recent Fundamental Advances and Emerging Biological and Biomimicking Applications. Adv Mater 33 , 2004349 (2021). Lin N, Dufresne A. Nanocellulose in biomedicine: Current status and future prospect. European Polymer Journal 59 , 302-325 (2014). Li X , et al. An overview of the development status and applications of cellulose-based functional materials. Cellulose 31 , 61-99 (2024). Parker RM , et al. The Self-Assembly of Cellulose Nanocrystals: Hierarchical Design of Visual Appearance. Adv Mater 30 , 1704477 (2018). Tran A, Boott CE, MacLachlan MJ. Understanding the Self-Assembly of Cellulose Nanocrystals—Toward Chiral Photonic Materials. Adv Mater 32 , 1905876 (2020). Huang Y , et al. Intense Left-handed Circularly Polarized Luminescence in Chiral Nematic Hydroxypropyl Cellulose Composite Films. Adv Mater 36 , 2308742 (2024). Nishio Y, Nada T, Hirata T, Fujita S, Sugimura K, Kamitakahara H. Handedness Inversion in Chiral Nematic (Ethyl)cellulose Solutions: Effects of Substituents and Temperature. Macromolecules 54 , 6014-6027 (2021). Liang H-L , et al. Roll-to-roll fabrication of touch-responsive cellulose photonic laminates. Nature Communications 9 , 4632 (2018). Kamita G , et al. Biocompatible and Sustainable Optical Strain Sensors for Large-Area Applications. Advanced Optical Materials 4 , 1950-1954 (2016). Chan CLC , et al. Visual Appearance of Chiral Nematic Cellulose-Based Photonic Films: Angular and Polarization Independent Color Response with a Twist. Adv Mater 31 , 1905151 (2019). Wang S , et al. High-substituted hydroxypropyl cellulose prepared by homogeneous method and its clouding and self-assembly behaviors. Carbohydrate Polymers 330 , 121822 (2024). Chan CLC , et al. 3D Printing of Liquid Crystalline Hydroxypropyl Cellulose—toward Tunable and Sustainable Volumetric Photonic Structures. Advanced Functional Materials 32 , 2108566 (2022). Barty-King CH , et al. Mechanochromic, Structurally Colored, and Edible Hydrogels Prepared from Hydroxypropyl Cellulose and Gelatin. Adv Mater 33 , 2102112 (2021). Wohlert M, Benselfelt T, Wågberg L, Furó I, Berglund LA, Wohlert J. Cellulose and the role of hydrogen bonds: not in charge of everything. Cellulose 29 , 1-23 (2022). Su Z , et al. Reconstruction of Cellulose Intermolecular Interactions from Hydrogen Bonds to Dynamic Covalent Networks Enables a Thermo-processable Cellulosic Plastic with Tunable Strength and Toughness. ACS Nano 17 , 21420-21431 (2023). Li X, Liu J, Guo Q, Zhang X, Tian M. Polymerizable Deep Eutectic Solvent-Based Skin-Like Elastomers with Dynamic Schemochrome and Self-Healing Ability. Small 18 , 2201012 (2022). Xu M , et al. Multifunctional chiral nematic cellulose nanocrystals/glycerol structural colored nanocomposites for intelligent responsive films, photonic inks and iridescent coatings. Journal of Materials Chemistry C 6 , 5391-5400 (2018). Wu M , et al. Cellulose-based photo-curable chiral nematic ink for direct-ink-writing 3D printing. Carbohydrate Polymers 352 , 123159 (2025). Zhang Z, Chen Z, Wang Y, Zhao Y, Shang L. Cholesteric Cellulose Liquid Crystals with Multifunctional Structural Colors. Advanced Functional Materials 32 , 2107242 (2022). Shopsowitz KE, Qi H, Hamad WY, MacLachlan MJ. Free-standing mesoporous silica films with tunable chiral nematic structures. Nature 468 , 422-425 (2010). Wu S , et al. Poly(vinyl alcohol) Hydrogels with Broad-Range Tunable Mechanical Properties via the Hofmeister Effect. Adv Mater 33 , 2007829 (2021). Hribar B, Southall NT, Vlachy V, Dill KA. How Ions Affect the Structure of Water. Journal of the American Chemical Society 124 , 12302-12311 (2002). Lin X , et al. A highly aligned X-shaped hydrogel fiber via cooperative roles of amorphous and crystalline network mediated by Hofmeister effect. Polymer 292 , 126538 (2024). He Q, Huang Y, Wang S. Hofmeister Effect-Assisted One Step Fabrication of Ductile and Strong Gelatin Hydrogels. Advanced Functional Materials 28 , 1705069 (2018). Li Y , et al. Multiscale Structural Characterization of a Smectic Liquid Crystalline Elastomer upon Mechanical Deformation Using Neutron Scattering. Macromolecules 54 , 10574-10582 (2021). Sorensen CM, Wang GM. Size distribution effect on the power law regime of the structure factor of fractal aggregates. Physical Review E 60 , 7143-7148 (1999). Polizzi S, Spinozzi F. Small Angle X-Ray Scattering (SAXS) with Synchrotron Radiation Sources. In: Synchrotron Radiation: Basics, Methods and Applications (eds Mobilio S, Boscherini F, Meneghini C). Springer Berlin Heidelberg (2015). Wang S , et al. Coassembling Hydroxypropyl Cellulose into a Chiral Nematic Composite and Patternization with a Photomask and Direct Ink Writing. ACS Applied Polymer Materials 5 , 9642-9649 (2023). Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryMaterialPlantDerivedBiobasedLiquidCrystalElastomerwithOndemandMechanochromicResponsecp.docx Supplementary Material of Plant-Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6702808","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":465294720,"identity":"87ba29a6-791f-4c67-a153-49b2356f7387","order_by":0,"name":"Jiaqi Guo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABHklEQVRIiWNgGAWjYDACZjACA8YHHyr+yxmA2QYWRGlhNpxxhtnYAMw3kCBkERiwSXO2MSdugPBxazE4znv4c0HNHbvt7b2HjRnOsKVvZ+8/uuFHgQQDf3t3AjYtks18adIzjj1LnnPmXOLjggqe3J09h9lu9gAdJnHm7AZsWviZecyYedgOJ0tI5BgbzzgjkbvhRjLbDR6gFgMgG5sWNmYe4888/4Ba5N+YSfO2GaQbALXc/INHC9AWA6DKw3YSEjwgLQkJIC238dki2QxS2Xc4QYInxxgYyAcMN5w5bHZbxkCCB5dfDM6fATrs22F7CfYzhsCoPCBvcLzx2c03f2zk+Nt7sWqBgcQGdBEefMpBwJ6QglEwCkbBKBjBAADvnF8n69mECQAAAABJRU5ErkJggg==","orcid":"","institution":"University of Freiburg","correspondingAuthor":true,"prefix":"","firstName":"Jiaqi","middleName":"","lastName":"Guo","suffix":""},{"id":465294721,"identity":"5ae93e46-ac68-4daf-91eb-5cedb7b7f806","order_by":1,"name":"LuKuan Guo","email":"","orcid":"","institution":"Nanjing Forestry University","correspondingAuthor":false,"prefix":"","firstName":"LuKuan","middleName":"","lastName":"Guo","suffix":""},{"id":465294722,"identity":"5682df6e-0a8a-4b1c-8eac-f485382135cb","order_by":2,"name":"Jing Sun","email":"","orcid":"","institution":"Nanjing Forestry University","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Sun","suffix":""},{"id":465294723,"identity":"c6988f68-6f62-408e-b418-210fd3e66a6c","order_by":3,"name":"Xinxin Yan","email":"","orcid":"","institution":"Nanjing Forestry University","correspondingAuthor":false,"prefix":"","firstName":"Xinxin","middleName":"","lastName":"Yan","suffix":""},{"id":465294724,"identity":"d368ff98-f541-4c5b-9c92-d1a6e52cdfab","order_by":4,"name":"Xuemei Ge","email":"","orcid":"","institution":"Biopharm solutions, Inc. c/o Galaxy Bio, Inc","correspondingAuthor":false,"prefix":"","firstName":"Xuemei","middleName":"","lastName":"Ge","suffix":""},{"id":465294725,"identity":"26e1dc77-284c-4dfd-898f-44c92239c037","order_by":5,"name":"Lijie Li","email":"","orcid":"","institution":"Beijing Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Lijie","middleName":"","lastName":"Li","suffix":""},{"id":465294726,"identity":"19ad5fec-568b-433c-be0c-6a45a3797c1f","order_by":6,"name":"Pan Chen","email":"","orcid":"","institution":"Beijing Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Pan","middleName":"","lastName":"Chen","suffix":""},{"id":465294727,"identity":"c15a5684-cc3b-4c4e-bf98-c11b4a708478","order_by":7,"name":"Guang Chu","email":"","orcid":"https://orcid.org/0000-0003-1538-5276","institution":"Aalto University","correspondingAuthor":false,"prefix":"","firstName":"Guang","middleName":"","lastName":"Chu","suffix":""},{"id":465294728,"identity":"f4f5f985-188d-43bc-8038-bff4fe78d8b1","order_by":8,"name":"Junlong Song","email":"","orcid":"https://orcid.org/0000-0002-5271-8140","institution":"Nanjing Forestry University","correspondingAuthor":false,"prefix":"","firstName":"Junlong","middleName":"","lastName":"Song","suffix":""},{"id":465294729,"identity":"0f05369f-e857-448a-860b-d68902774eff","order_by":9,"name":"Yongcan Jin","email":"","orcid":"https://orcid.org/0000-0002-0748-3629","institution":"Nanjing Forestry University","correspondingAuthor":false,"prefix":"","firstName":"Yongcan","middleName":"","lastName":"Jin","suffix":""}],"badges":[],"createdAt":"2025-05-20 02:20:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6702808/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6702808/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83823500,"identity":"d3fed237-c5b3-4377-992f-6a22400adaf4","added_by":"auto","created_at":"2025-06-03 09:36:52","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":291334,"visible":true,"origin":"","legend":"\u003cp\u003eFabrication and optical properties of the HPC-PAA composite. (a) Schematic of the HPC-PAA composite fabrication process. (b) Linear correlation between AA concentration in HPC-PAA composites and their reflection peak wavelengths. Inset: representative photographs of composites at varying concentrations. (c) Circular dichroism (CD) spectra of the HPC-PAA composite with AA content of 12 wt.%. Inset: Photographs of the structural colored film under left- or right-handed circular polarizers. (d) Cross-sectional SEM image of the 14 wt.% HPC-PAA composite (scale bar: 500 nm). Inset: Macroscopic photograph of the composite (scale bar: 10 mm).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/22738795eef77609fc084878.png"},{"id":83823320,"identity":"2de07ad1-0e56-4cc9-a653-8c35d1b12494","added_by":"auto","created_at":"2025-06-03 09:28:52","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":321177,"visible":true,"origin":"","legend":"\u003cp\u003eInvestigation of the variation of H-bond on HPC-PAA elastomer. (a) Schematic illustration of the underlying mechanisms governing the interactions within HPC-PAA elastomers in H2O and ions solutions. (b) The tensile curves (\u003cem\u003eσ\u003c/em\u003e-\u003cem\u003eε\u003c/em\u003e) of elastomers prepared in 1 M Cl- solutions with different cations (Fe3+, Ca2+, K+, Zn2+, Na+). (c) The \u003cem\u003eσ\u003c/em\u003e-\u003cem\u003eε\u003c/em\u003e curve for the HPC-PAA elastomers prepared in the 1 M Na+ solutions with different anions (Cl-, SO42-, CO32-). (d), (e) Split-peak fitting of H-bond peaks on FTIR spectra (4000 ~ 2500 cm-1) of HPC-PAA elastomer (with AA content of 14wt.%) prepared in H2O, Na2SO4, respectively. Peak colors indicate bond strength: Blue: weak H-bond; Green: medium H-bond; Red: Strong H-bond. (f) Area ratio of FTIR peaks corresponding to different proportion of strong, medium and weak H-bond of HPC-PAA elastomer prepared in H2O, NaCl, Na2SO4, respectively.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/61fe6a3bff105938c32fe189.png"},{"id":83822483,"identity":"6a0b97de-812c-4df5-ae0d-dd6633122979","added_by":"auto","created_at":"2025-06-03 09:20:52","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":420793,"visible":true,"origin":"","legend":"\u003cp\u003eMD simulations of HPC-PAA LCE. (a), (b) MD of HPC-PAA elastomers prepared in H\u003csub\u003e2\u003c/sub\u003eO and Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution. (c) Interaction energy (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eInt\u003c/sub\u003e) between HPC and PAA of HPC-PAA elastomer prepared in H\u003csub\u003e2\u003c/sub\u003eO, NaCl, Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4 \u003c/sub\u003eas a function of time by MD. (d) Schematic illustration of the interaction between H\u003csub\u003e2\u003c/sub\u003eO molecules, ions and the elastomer during immersion in solution. (e) The ratio of free water to solvation water (R) in H\u003csub\u003e2\u003c/sub\u003eO and Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4 \u003c/sub\u003esolutions by MD. (f) H-bond interaction energy (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eH-bond Int\u003c/sub\u003e) between H\u003csub\u003e2\u003c/sub\u003eO molecules of H\u003csub\u003e2\u003c/sub\u003eO, NaCl and Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4 \u003c/sub\u003esolution\u003csub\u003e \u003c/sub\u003eby MD.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/fd9a0f63bdb18f5e0312be3a.png"},{"id":83822479,"identity":"92546b48-e144-4a0a-a93a-bff690132a81","added_by":"auto","created_at":"2025-06-03 09:20:52","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":500126,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The schematic illustration of tensile induced helical pitch changes. (b) Pressing induced structural color changes of HPC-PAA elastomers. As elastomers are subjected to an increasing pressure, its coloration undergoes a gradual transition from red to blue. Scale bar: 5 mm. (c) Tensile induced structural color changes of HPC-PAA elastomers. As elastomers are subjected to a gradual elongation from 100% to 600%, its color undergoes a transformation, shifting from red to blue. (d) The linear relationship between tensile deformation and reflection peak wavelength. (e) The linear relationship between press deformation and reflection peak wavelength. (f) Integrated SAXS profiles of the elastomer corresponding to various stretching states (initial and stretched to 200%, 400% and 600% strain). (g) Integrated WAXS profiles of the elastomer corresponding to various stretching states. (h) X-ray scattering patterns of the initial and 600% stretched elastomer. Top row: SAXS patterns; Bottom row: WAXS patterns.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/5a6bda4154b18876dd0bc5af.png"},{"id":83822486,"identity":"0ca2f737-94f8-4669-bb3e-47fa662b3399","added_by":"auto","created_at":"2025-06-03 09:20:52","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":578872,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic illustration of the HPC-PAA elastomer and its self-healing ability after soaking in Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution. The optical microscope images show the cut and the self-healed elastomers after 60 mins of recovery. (b) Tensile (\u003cem\u003eσ\u003c/em\u003e-\u003cem\u003eε\u003c/em\u003e) curves of the original and self-healing elastomers following cutting and soaking in 1 M Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e for 30 and 60 mins. (c) The laser confocal images of active cells following co-cultured with HPC-PAA elastomers. The images, presented from left to right, depict the blank control group, cells co-cultured with HPC-PAA (NaCl) elastomer, and the cells co-cultured with HPC-PAA (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) elastomer. (d) Cell viability of CK cells co-cultured with elastomers. (e) Digital images showing the degradation of HPC-PAA (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) elastomer over 30 days (the elastomer was placed on an iron net). Scale bar: 10 mm.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/a2550cc0f3de6a4740af44d7.png"},{"id":83822487,"identity":"2050e035-883f-4bfe-8333-ac0320e1c88f","added_by":"auto","created_at":"2025-06-03 09:20:52","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":378377,"visible":true,"origin":"","legend":"\u003cp\u003eIllustrates various applications of the HPC-PAA elastomer in motion detection, training assistance and pattern encryption. (a) A schematic diagram of finger-bending elastomer, showing structural color changes under deformation. (b) A schematic diagram of a stretchable and reciprocating elastomer used for children’s rehabilitation training. The elastomer stretches to different degrees, displaying a color gradient from red to blue, and can revert to its original state upon the removal of external force. (c) Color change and reflectance spectra corresponding to finger joint motion, with an inset showing photographs of the coloration at different bending state. (d) Reflectance spectra of the elastomer as it is stretched, demonstrating gradual color changes (from right to left). (e) Reflectance spectra of elastomer upon the gradual removal of external force, returning to its original state (from left to right). (f) During a stretch cycle, the elastomer’s color completely and reversibly returns to its original state. Scale bar: 20 mm. (g) Pattern encryption: Letters “A” and “C” along with patterns on the elastomer indistinct when unstretched, but become clearly visible with a color shift from red to blue-green when stretched. Scale bar: 20 mm.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/136bfebd52f64bb269828793.png"},{"id":83824486,"identity":"513082ec-e2b2-4f95-90a0-a67829752aad","added_by":"auto","created_at":"2025-06-03 09:44:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3162672,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/fc5b531e-54b2-49e8-accf-e7ba9fc15563.pdf"},{"id":83824484,"identity":"e8972093-d148-4768-81aa-93f76d655520","added_by":"auto","created_at":"2025-06-03 09:44:52","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1399305,"visible":true,"origin":"","legend":"Supplementary Material of Plant-Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response","description":"","filename":"SupplementaryMaterialPlantDerivedBiobasedLiquidCrystalElastomerwithOndemandMechanochromicResponsecp.docx","url":"https://assets-eu.researchsquare.com/files/rs-6702808/v1/d3960ea9240f50dda6ac1c9c.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Plant Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOur society has set the course of sustainability to define the next frontier of material science, namely, engineering materials from renewable and eco-conscious feedstocks\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Among the various types of functional materials, liquid crystal elastomers (LCEs) are a unique class of materials that contain the molecular orientational order of liquid crystal with the stretchiness and durability of elastomer, notable for their remarkable anisotropy and high responsiveness to external stimulus\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. This unique combination of anisotropy and dynamic sensitivity to external cues making LCEs as transformative candidates for the next-generation technologies such as soft robotics\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e, adaptive actuators\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e, biomimetic artificial muscles\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, and tunable photonic systems\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. However, conventional LCE synthesis relies heavily on petrochemical-derived precursors (\u003cem\u003ee.g.\u003c/em\u003e, diacrylates\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, RM82\u003csup\u003e13\u003c/sup\u003e and RM257\u003csup\u003e5\u003c/sup\u003e), which pose significant environmental risks due to their toxicity and persistence in ecosystems. Addressing this limitation, the pursuit of biodegradable, bio-sourced LCEs has become a critical priority to reconcile high-performance functionality with ecological sustainability\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eCellulose, the most abundant plant-derived biopolymer in nature, is a linear polysaccharide composed of repeating β-(1\u0026ndash;4)-linked D-glucose units\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Each glucose monomer contains three hydroxyl groups (-OH) at the C2, C3, and C6 positions, which participate in extensive intra- and intermolecular hydrogen bond (H-bond)\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. This unique molecular architecture underpins cellulose\u0026rsquo;s hierarchical structure, crystallinity, and remarkable mechanical stability, making it a cornerstone of plant cell walls and a critical resource for sustainable materials development\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Owing to the inherent chirality of its molecular structure, some cellulose derivatives or rod-like nanoparticles can self-assemble into a chiral nematic organization with different handedness, creating vivid structural color that due to the selective reflection of circularly polarized light in the visible range\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, 20 21\u003c/sup\u003e. For instance, hydroxypropyl cellulose (HPC) is a kind of biocompatible cellulose ether that has been widely used in pharmaceutical and food industries\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. It can be dissolved in water and organic solvents across varying concentrations, displaying both lyotropic and thermotropic phase behavior due to its capacity to self-assemble into right-handed chiral nematic phase\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Recently, Chan et al.\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e developed HPC-based 3D-printing inks for creating volumetric objects with tunable structural color, while Barty-King et al.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e produced self-supporting photonic hydrogels with HPC and gelatin, retaining mechanochromism for responsive materials and colorant-free decoration. These results demonstrate the extraordinary versatility of HPC as the building blocks for the design and fabrication of low-cost and ecofriendly functional photonic materials. Although HPC derived chiral nematic liquid crystals have been extensively studied from the perspective of self-assembly, microfabrication, and photonic sensing, to the best of our knowledge, no attempt has yet been made to develop a chiral nematic LCE with on-demand mechanochromic response. The intrinsic structural characteristics of cellulose make it unsuitable for constructing LCE due to its low stretchability. The glucose rings in cellulose chain impart rigidity to its structure\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e, while the -OH groups within the molecular structure form extensive internal H-bond\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. These bonds significantly restrict the cellulose chain flexibility\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e and result in poor stretchability of cellulose-based materials\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn this work, we employ HPC as the primary raw material to prepare optically tunable liquid crystal complexes with the minor addition of acrylic acid (AA). By adjusting the composition ratio between HPC and AA, the resulting polymer composite display varying structural color due to the manipulation of the chiral nematic HPC helical pitch. After crosslinking the monomers into poly (acrylic acid) (PAA), the chiral nematic LCE is subsequently formed by immersing the HPC-PAA complexes in a sodium solution, which modulates the intermolecular interactions via the Hofmeister effect with either salt-in or salt-out process. The obtained HPC-PAA LCE exhibits exceptional mechanochromic behavior with structural color shifting in response to applied force, implying the changes of helical structure of the liquid crystal matrix. These HPC-derived LCEs, with their outstanding visible light sensing properties, are expected to have broad applications and provide a novel approach for advancing the use of cellulosic materials.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe preparation of chiral nematic liquid crystalline HPC-PAA composite is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea. This process involved the self-co-assembly of HPC with the UV-induced polymerization of AA, facilitated by the crosslinker PEGDA and the photo-initiator LAP. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb, the obtained composite films exhibit a distinct color transition from blue to red with increasing of AA content, implying the increase of helical pitch of HPC matrix. The peak reflectance wavelength of the HPC-PAA composites shifts progressively with increasing AA concentration, displaying a linear correlation. Specifically, increasing the AA content from 10\u0026ndash;15% results in a pronounced redshift of the peak wavelength, from 452 to 770 nm. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec presents the circular dichroism (CD) spectra of the HPC-PAA composite, characterized by a strong negative Cotton effect, resulting from the right-handed helical organization of the HPC matrix\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. Besides, when the sample was observed through a circular polarizer with opposite handedness, the HPC-PAA composite displayed a vivid structural color under a right-handed circular polarizer, whereas it appears transparent when viewed through a left-handed circular polarizer, indicative of the selective reflection of right-handed circularly polarized light from the HPC-PAA system.\u003c/p\u003e \u003cp\u003eIt is well known that the structural coloration in chiral nematic liquid crystal originates from its well-ordered layered structure, acting as 1D photonic crystal\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed, the cross-section SEM image of the HPC-PAA composite (with AA content of 14 wt.%) reveals a periodic layered structure that due to the helical arrangement of HPC. This phenomenon can be attributed to the lyotropic behavior of HPC that form chiral nematic liquid crystal phase above critical concentration and further preserved into solid films\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. The measured distance between neighboring layers can be termed as half pitch of the chiral nematic film, which is proportional to the reflected wavelength peak\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e. Besides, we also notice that the addition of AA can expand the helical pitch of HPC and stabilize its cholesteric structure via polymerization, thereby shifting the reflection wavelength from blue to red.\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eOwing to the high density of -OH groups within HPC, the HPC-PAA composite exhibit intrinsic inelasticity due to the formation of internal H-bond network. To impart stretchability, it was necessary to disrupt these static H-bonds and introduce dynamic, reversible interactions. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea, the hydrophilic nature of the -OH groups enable efficient interaction with water molecules upon immersion. This interaction disrupts the intermolecular H-bond network, leading to a decrease in both strength and tensile properties (0.01 MPa, 155%, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). In recent years, ion-solution immersion has emerged as an effective approach for modulating the mechanical properties of hydrogels, in accordance with the Hofmeister effect\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. Research indicates that cations (e.g., K⁺, Na⁺) enhance polymer hydration by weakening chain interactions through salting-out effects, whereas anions (e.g., SO₄\u0026sup2;⁻, CO₃\u0026sup2;⁻) disrupt hydration layers, thereby strengthening chain interactions through salting-in effects (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea)\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eBased on these principles, a range of common anions and cations were employed to investigate the influence of ions on elastomer mechanical properties. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, the elastomer obtained by soaking in ions solutions with identical Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e anions but varying cations showed significant difference in mechanical properties. In specific, the elastomer soaked in Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e solutions containing Ca\u003csup\u003e2+\u003c/sup\u003e and Na\u003csup\u003e+\u003c/sup\u003e demonstrate the best performance, with a stress of 0.2 MPa for CaCl\u003csub\u003e2\u003c/sub\u003e and a strain of 720% for NaCl. A detailed comparative analysis of the effects of CaCl\u003csub\u003e2\u003c/sub\u003e and NaCl solutions concentrations on the mechanical properties of elastomers revealed that the optimal comprehensive performance was achieved at a concentration of 1M (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003ea, b). FTIR analysis shows that the introduction of ions broadens the of -OH stretching peak around 3400 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and enhances the carbonyl group absorption peaks at 1630 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e compared to pure HPC and HPC-PAA composite (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003ec). These changes can be attribute to the ions\u0026rsquo; ability to modulate the intermolecular H-bonds within the polymer chains, thereby altering their arrangement and conformation\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eTo enhance the tensile elongation of the elastomer, Na⁺ was selected as the cation of interest, and the effects of various anions on the elastomer\u0026rsquo;s mechanical properties were subsequently investigated. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec, the elastomer prepared by soaking in Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e and NaCl demonstrated nearly comparable tensile strains, ranging from 550 to 700%, but with a notable difference in breaking stress. Specifically, the elastomer soaked in Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e exhibited a breaking stress of 0.27 MPa, significantly higher than 0.13 MPa observed for NaCl-soaked elastomer. Therefore, the HPC-PAA elastomer prepared with Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e displayed the superior overall mechanical performance and was selected for further testing.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eUpon immersion in H₂O and ionic solutions, the -OH groups of HPC formed H-bonds with H₂O, as evidenced by the displacement and broadening of the -OH stretching vibration peak in the FTIR spectrum. The prepared elastomers exhibited a distinct H-bond absorption peak (near 3500\u0026thinsp;\u0026minus;\u0026thinsp;3200 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003csup\u003e25\u003c/sup\u003e, which could be deconvoluted into multiple types of H-bonds with varying intensities (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed, e, and Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003ec, d, e). Specifically, split-peak fitting analysis of the H-bonds in the 4000\u0026ndash;2500 cm⁻\u0026sup1; range for elastomers immersed in H₂O revealed two distinct peaks at 3230 cm⁻\u0026sup1; (strong) and 3410 cm⁻\u0026sup1; (medium). For elastomers immersed in Na₂SO₄ and NaCl solutions, a shift in peak intensities at 3230 cm⁻\u0026sup1; and 3410 cm⁻\u0026sup1; was observed, along with the emergence of a new peak at 3583 cm⁻\u0026sup1; (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee and Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003ed, e). These observations suggested the formation of weaker H-bonds compared to those in H₂O-immersed elastomers. A similar phenomenon was observed in elastomer prepared in CaCl₂ solution (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003ee). As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef, the ratio of strong to medium H-bonds decreased in elastomers processed with Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e and NaCl solutions, while an increase in weak H-bonds was observed. This indicates that the elastomer prepared by soaking in solutions containing ions exhibited weaker H-bonds compared to that prepared in H₂O. Furthermore, the H-bonds within the elastomer also exhibited a dynamic and reversible nature. To assess the mechanical elasticity of the HPC-PAA elastomer soaked in Na₂SO₄ solution, cyclic compressive tests were performed over 50 cycles (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003ef). The elastomer demonstrated an initial tensile strain of 300% and a compressive stress of 0.15 MPa. Although a hysteresis loop appeared in subsequent cycles, the stress-strain curve remained reversible, with the hysteresis area largely unchanged. This suggests that while part of H-bonds was partially disrupted during deformation, their partial reversibility helped maintain material integrity.\u003c/p\u003e \u003cp\u003eThe variation in H-bonds, as an internal interaction within the elastomer, could be attributed to the infiltration of H\u003csub\u003e2\u003c/sub\u003eO molecules during solution soaking. These molecules affected the binding between neighboring HPC chains, thereby reducing tensile strength and increasing elongation at break. To investigate these interactions at the molecular level, molecular dynamics (MD) simulations were performed to quantify the interaction among H\u003csub\u003e2\u003c/sub\u003eO, HPC, and PAA (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea, b), the relative amount of which could provide insights into the binding energies of various ions with water, and shed light on the molecular mechanisms underlying the observed macroscopic behaviors.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec, the interaction (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eInt\u003c/sub\u003e) of the elastomer obtained from NaCl solution (\u0026asymp; -3300 kcal/mol) and Na₂SO₄ solution (\u0026asymp; -4200 kcal/mol) was significantly more negative than that of the elastomer obtained from H₂O (\u0026asymp; -2300 kcal/mol). Furthermore, the absolute value of the \u003cem\u003eE\u003c/em\u003e\u003csub\u003eInt\u003c/sub\u003e of the elastomer processed in aqueous solutions followed the order: H\u003csub\u003e2\u003c/sub\u003eO˂ NaCl˂ Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e. It is well established that a greater the negative binding energy, with a larger absolute value, corresponds to attraction between group pairs and reflects a relative more stable system. These findings indicate that the HPC-PAA elastomer obtained from Na₂SO₄ solution exhibited the highest stability among all tested aqueous conditions, leading to superior tensile performance (0.27 MPa, 575%).\u003c/p\u003e \u003cp\u003eAccording to Hofmeister theory\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e, kosmotropic anions, such as SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e, Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e, are known to strongly hydrated with H\u003csub\u003e2\u003c/sub\u003eO molecules. This hydration reduces the availability of free H\u003csub\u003e2\u003c/sub\u003eO molecules that can interact with polymer chains, thereby disrupting the H-bonds between them. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed, the formation of solvation water due to ion hydration decreased the proportion of free water molecules available for interaction with HPC. Consequently, elastomers soaked in ions solutions exhibit a reduced disruptive effect on HPC interactions compared to those soaked in pure water. MD simulations revealed that that the ratio of free water to solvation water is lower for Na₂SO₄ (7%) than for NaCl (13%) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ee). While H\u003csub\u003e2\u003c/sub\u003eO imparts deformability to the elastomer under tensile or compressive forces, an excess of water reduces the material\u0026rsquo;s strength. This difference is consistent with the observed variations in the mechanical behavior of the elastomers.\u003c/p\u003e \u003cp\u003eFurthermore, the association of ions with H\u003csub\u003e2\u003c/sub\u003eO molecules in ionic solutions also affects the ability of water molecules to form H-bonds with each other. To further understand how the presence of ions reduces the availability of free water, we investigated the H-bond strengths between H\u003csub\u003e2\u003c/sub\u003eO molecules in both pure water and ions solutions. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ef, the H-bond interaction (E\u003csub\u003eH\u0026minus;bond Int\u003c/sub\u003e) energy reveals that pure H\u003csub\u003e2\u003c/sub\u003eO exhibits the most negative and highest absolute value (-647 kcal/mol), indicating the strongest H-bonding. In contrast, the Na₂SO₄ solution exhibits the weakest H-bond interaction energy (-540 kcal/mol). This evidence demonstrates that ions in aqueous solutions can effectively regulate H-bonding in water, thereby modulating the dynamic interaction forces within the elastomer.\u003c/p\u003e \u003cp\u003eThe HPC-PAA composite (with AA content of 14 wt.%) exhibits a red appearance due to the formation of an ordered helical structure (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed), where the helical pitch is proportional to the wavelength of visible light. Upon transformed into an elastomer by soaking in Na₂SO₄ solution, the material can undergo deformation under external forces (tension or pressure). As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea, deformation can reduce the helical pitch, shifting the reflected light to shorter wavelengths and causing the material to transition from red to green and then to blue as deformation increases, thus displaying distinct colors at different deformation levels. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb shows that, under compressive deformation, the HPC-PAA elastomer exhibits a gradual color transition from red to blue, with each color appearing vividly. This chromatic response is also observed under tensile deformation (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec). Specifically, when subjected to tensile strains of 200%, 400%, and 600%, the elastomer sequentially transitions from its initial red hue to orange, green, and blue.\u003c/p\u003e \u003cp\u003eThe correlation between color, deformation, and applied force is of significant interest, prompting a detailed investigation into the quantitative relationships among these variables. A linear relationship has been established between tensile stress, deformation ratio, and the wavelength of reflected light, thereby elucidating the underlying mechanisms of this phenomenon. Specifically, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed, the elongation ratio L/L\u003csub\u003e0\u003c/sub\u003e increases proportionally from 1 to 6 as tensile stress rises from 0.08 to 0.24 MPa, with the reflection wavelength decreasing from 700 to 450 nm. A similar linear trend is observed under compressive deformation (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eg), where the compression ratio L/L\u003csub\u003e0\u003c/sub\u003e increases from 10\u0026ndash;60% as the compressive stress rises from 0.1 to 0.8 MPa, and the reflection wavelength decreases correspondingly from 700 to 450 nm. The demonstrated linear correlation between applied force, deformation, and the wavelength of reflected light portends significant potential for future applications of the elastomer.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef displays SAXS profiles of the elastomer subjected to varying degrees of mechanical stretching. The patterns illustrate the relationship between scattering intensity (\u003cem\u003eI\u003c/em\u003e) and the scattering vector (\u003cem\u003eq\u003c/em\u003e), providing insights into the material\u0026rsquo;s molecular arrangement and crystalline structure. The SAXS profiles are analyzed using Bragg\u0026rsquo;s law\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e,, which inversely relates the diffraction angle \u003cem\u003eθ\u003c/em\u003e to the interplanar spacing \u003cem\u003ed\u003c/em\u003e, facilitating the analysis of sample morphology across micro to macro scales as \u003cem\u003eq\u003c/em\u003e decreases. The power-law model correlates the curve\u0026rsquo;s slope to the sample\u0026rsquo;s fractal dimension (\u003cem\u003edf\u003c/em\u003e), while Guinier\u0026rsquo;s law links the shoulder region to the radius of gyration (\u003cem\u003eRg\u003c/em\u003e). The pre- and post-stretching SAXS patterns are comparable, indicating minimal overall morphological changes despite significant influences on finer structures. In the log(\u003cem\u003eq)\u003c/em\u003e range of 0.04\u0026thinsp;~\u0026thinsp;0.01, \u003cem\u003edf\u003c/em\u003e values of 3\u0026thinsp;~\u0026thinsp;4 suggest complex internal structures and rough surfaces, indicating microscale interactions between HPC and PAA. Values of \u003cem\u003edf\u003c/em\u003e between 17\u0026thinsp;~\u0026thinsp;20 in the log(\u003cem\u003eq\u003c/em\u003e) range of 0.008\u0026thinsp;~\u0026thinsp;0.005 hint at fine pores or ordered structures, suggesting AA polymerization and HPC self-assembly. For log(\u003cem\u003eq\u003c/em\u003e) values of 0.002\u0026thinsp;~\u0026thinsp;0.001, \u003cem\u003edf\u003c/em\u003e values of 1\u0026thinsp;~\u0026thinsp;2.5 imply one-dimensional arrangements at larger scales. The obtained long periods of 288.7, 290.6, 296.3, and 292.5 nm for initial and stretched samples (200\u0026ndash;600%) indicate that the periodic arrangement of crystalline and amorphous regions remains nearly stable despite stretching. The SAXS patterns demonstrate a morphological transition in the HPC-PAA elastomer from a circular to an elliptical scattering signature upon stretching to 600% (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eh). This shape change phenomenon is also observed at lower strains of 200% and 400% (Fig. S3). The transition is attributed to the development of anisotropic structures, molecular chain orientation, and crystal alignment along the stretch direction.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eg presents the WAXS profiles of the HPC-PAA elastomer under increasing mechanical strains. The initial pattern exhibits two pseudo-Bragg peaks at \u003cem\u003eq\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.51 A\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (2θ\u0026thinsp;=\u0026thinsp;8\u0026deg;) and \u003cem\u003eq\u003c/em\u003e\u003csub\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1.51 A\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (2θ\u0026thinsp;=\u0026thinsp;20.8\u0026deg;), corresponding to d-spacings of \u003cem\u003ed\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;2\u003cem\u003eπ\u003c/em\u003e/\u003cem\u003eq\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;12.32 \u0026Aring; and \u003cem\u003ed\u003c/em\u003e\u003csub\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;2\u003cem\u003eπ\u003c/em\u003e/\u003cem\u003eq\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;4.16 \u0026Aring;, respectively\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. The increasing of strain induces the diffraction peaks shifting towards lower \u003cem\u003eq\u003c/em\u003e-values. According to Bragg\u0026rsquo;s law, this shift suggests an increase in lattice constants and interplanar spacing, indicative of structural reorganization under tension. While peak intensities are relatively stable at 200% strain, a significant decrease is observed at 400% and 600% strain, signifying a decrease in crystallinity, likely due to anisotropic deformation, which leads to a diminished volume fraction of ordered crystalline domains. The initial WAXS patterns of the elastomer (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eh, bottom row) display two concentric rings, signifying an isotropic structure with randomly oriented crystal domains. Upon stretching, these rings evolve into meridionally oriented arcs, indicating preferential orientation of crystal domains and the development of partially aligned microstructures, as evidenced by the altered scattering intensity in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eg. The orientation parameter \u003cem\u003eS\u003c/em\u003e, derived from the WAXS patterns, increases from 0.264\u0026ndash;4.508% with 600% deformation, reflecting enhanced molecular alignment along the strain direction and a concomitant increase in anisotropy of physical properties.\u003c/p\u003e \u003cp\u003eCharacterizing the structural dynamics of the HPC-PAA elastomer under mechanical deformation provides essential insights into its functional attributes, which may offer substantial performance and sustainability advantages. These properties make the elastomer a promising candidate for advanced applications that prioritize human health and well-being. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea illustrates the elastomer\u0026rsquo;s self-healing ability after a cut, following immersion in a Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution. The interaction between water molecules and ions in the solution with the -OH of HPC and PAA promotes H-bonds formation, facilitating the reorientation and rejoining of severed polymer chains. This process restores the elastomer\u0026rsquo;s cohesive properties, as shown by the visual comparison in the accompanying image, where the top row depicts the initial cut state and the bottom row shows the healed state after 60 mins. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb further evaluates the mechanical performance of the healed elastomer. The \u0026ldquo;Original\u0026rdquo; curve, representing the material\u0026rsquo;s initial state, shows a tensile strength of 0.26 MPa and a strain of 600%. After 30 mins of healing, there is a noticeable decrease in mechanical strength. However, after 60 mins, the material recovers to a tensile strength of 0.15 MPa (57.7% of the original), while maintaining a strain of 600%, indicating a significant recovery of mechanical integrity over time.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFurthermore, HPC-PAA elastomers demonstrate exceptional biocompatibility. As shown in the Fluorescence Microscopy images of viable cells presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec, the control group displays a uniform distribution of green fluorescence, indicating viable cells. In contrast, the images for HPC-PAA (NaCl) and HPC-PAA (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) elastomers reveal a partial red fluorescence, signifying non-viable cells. However, only few of non-viable cells were observed during the experiment, indicating a high degree of cytocompatibility for the elastomer, despite a minor cytotoxic effect compared to the controls. Additional quantification of cell viability, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed, reveals that the cell viability within the experimental groups is approximately 91% for HPC-PAA (NaCl) and 94% for HPC-PAA (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e). These findings support the conclusion that the elastomers exhibit good biocompatibility, making them suitable for potential biological applications.\u003c/p\u003e \u003cp\u003eAdditionally, the HPC-PAA elastomer, derived from natural resources, exhibits excellent biodegradability. To evaluate its environmental degradability, elastomer samples were placed on an outdoor iron mesh, suspended above the soil. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ee, the HPC-PAA elastomer undergoes environmental degradation. Over a period of 10 to 20 days, the samples progressively reduced in size, indicative of increasing degradation. By day 30, the samples were almost entirely degraded. This observation confirms that the prepared elastomers display exceptional degradability in natural environments. The combination of self-healing, biocompatibility, and biodegradability enhances the performance of the HPC-PAA elastomer, while aligning with sustainable development principles. Together, these multifunctional attributes support the design of sustainable and safe biomedical devices, emphasizing the material\u0026rsquo;s potential for green development applications.\u003c/p\u003e \u003cp\u003eThe superior mechanochromic properties of HPC-PAA elastomers make them ideal for human motion detection applications, such as monitoring finger joint movements. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea, the material exhibits a distinct color changes in response to varying degrees of finger bending (from 0\u0026deg; to \u0026gt;\u0026thinsp;90\u0026deg;), allowing for visual assessment of finger motion through color variation. Specifically, the color shift is closely correlated with the bending angle. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec, the material reflects red light (\u0026asymp;\u0026thinsp;700 nm) when unbent, green light (\u0026asymp;\u0026thinsp;580 nm) when bent at 90\u0026deg;, and blue light (\u0026asymp;\u0026thinsp;470 nm) when bent to 135\u0026deg;. This precise correlation between color and bending angle underscores the potential of HPC-PAA elastomers for accurate, non-invasive motion sensing.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThis HPC-based elastomer, characterized by its self-healing and stretch-ability, offers a novel solution for pediatric rehabilitation. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb, the device\u0026rsquo;s cyclic stretching action is particularly well-suited for repetitive exercises, a key component in upper limb strength recovery. The elastomer\u0026rsquo;s color-changing response to stretching presents immediate visual feedback, which simplifies the training process and enhances accessibility for users of all ages. This feature not only provides an intuitive way to track exercise performance, but also engages children through an interactive element, thereby boosting their motivation and adherence to prescribed exercises. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ef shows that the elastomer\u0026rsquo;s color transitions from transparent to red upon stretching, then progresses to green and blue. Upon the release of force, the elastomer reverts to its original transparent state, a reversible process that can be repeated. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ed presents four distinct wavelength peaks at 738, 632, 535, and 447 nm, corresponding to the color progression from transparent to blue during stretching. In contrast, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ee shows four peaks at 476, 551, 621, and 717 nm during recovery, from blue back to transparent, indicating the elastomer\u0026rsquo;s robustness and suitability for applications that require repeated mechanical deformation and visual feedback.\u003c/p\u003e \u003cp\u003eFurthermore, the color-changing property of this material has been harnessed for encryption applications, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eg. By precisely controlling the extent of cross-linking within the elastomeric matrix, patterns such as letters (A, C) and motifs (a tree) can be imprinted onto the elastomer surface. Additional examples, including letters (B, D) and a flower motif, are shown in Fig. S4. Under non-stretched conditions, the imprinted patterns remain inconspicuous and difficult to detect. However, upon mechanical stretching, these patterns emerge with striking clarity. Notably, as the elastomer is subjected to tensile forces that induce color shifts towards red and blue-green, the contrast and definition of the patterns are significantly enhanced. This unique characteristic endows the elastomer with superior cryptographic potential, making it a versatile material for secure device applications.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we successfully developed a novel sustainable based elastomer that utilizes cellulose derivative as the primary material (constituting over 85%) and exhibits precise mechanochromic properties, enabling selective reflection of right-handed circularly polarized light. The composite containing 14% AA exhibits a red color with a helical pitch of 440\u0026thinsp;\u0026plusmn;\u0026thinsp;72 nm. Fabricated via immersion in a 1 M Na₂SO₄ solution, the elastomer demonstrates excellent mechanical behavior, with a tensile strength of 0.27 MPa, 575% elongation. The Na₂SO₄ ions regulate water molecule penetration, weakening H-bonds between H\u003csub\u003e2\u003c/sub\u003eO molecules, which enhances the material\u0026rsquo;s tensile strength. A linear relationship was established between external force, deformation ratio, and reflection wavelength, highlighting the material\u0026rsquo;s sensitivity to mechanical stimuli. The elastomer also exhibits robust self-healing capabilities, recovering over 57% of its original strength and maintaining nearly identical deformation after 60 mins. Additionally, it demonstrates high biocompatibility (cell viability\u0026thinsp;\u0026gt;\u0026thinsp;90%) and complete degradation within 30 days in a natural outdoor environment. The material\u0026rsquo;s color-changing properties further enable applications in rehabilitation and pattern encryption, offering a versatile platform for secure devices and exercise guidance. Overall, the HPC-PAA elastomer represents a promising material for sustainable and multifunctional applications.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eMaterials\u003c/h2\u003e \u003cp\u003eAll chemicals were used as received without further purification. Hydroxypropyl cellulose (HPC dry powder, HPC grade: SSL, \u003cem\u003eM\u003c/em\u003e\u003csub\u003eW\u003c/sub\u003e= 40000 g\u0026middot;mol⁻\u0026sup1;, as reported by manufacturer) was purchased from Nippon Soda Co., Ltd. Acrylic acid (AA), poly (ethylene glycol) diacrylate (PEGDA), and lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) were purchased from Shanghai Macklin Biochemical Co., Ltd. Deionized water with resistivity of 18.2 MΩ\u0026middot;cm was prepared by Biosafer water purification system (Biosafer-20AS, China). Mouse L929 fibroblasts cell was supplied by ATCC. Dulbecco\u0026rsquo;s Modified Eagle Medium (DMEM) and others of the bio-related reagents were purchased from Meilunbio Co., Ltd, Dalian, China.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eCharacterization\u003c/h3\u003e\n\u003cp\u003ePolarized optical microscopy (POM) imaging was carried out on Mshot microscope (MP41, China) with images taken by polarizers in a perpendicular arrangement, which allowed identification of the anisotropy of the composites. Images were taken with camera (Sony IMX906, resolution of 50M pixels). UV-vis spectroscopy was performed on an ideaoptic-BSC spectrophotometer (iDH2000-BSC, China). Fourier transform infrared (FTIR) spectra were conducted on VERTEX 80 V infrared spectrometer (Bruker, Germany). FTIR spectroscopy was performed in the range of 400 to 4000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with a spectra resolution of 2 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The mechanical properties of the elastomers were evaluated through tensile and cyclic stretching tests using a Universal Tensile Testing Machine (AGS-X, Shimadzu, Japan). Specimens with a width of 10 mm and a gauge length of 10 mm were stretched at a constant rate of 20 mm/min, and all tests were conducted at room temperature. The cross-section morphologies of the samples were characterized using a high-resolution scanning electron microscope (Regulus 8100, Hitachi, Japan) at an accelerating voltage of 3 kV. Before characterization, the samples were rapidly frozen in liquid nitrogen and cryofractured to expose their internal structure, then mounted on a specimen stage and sputter-coated with a 10-nm gold layer for 100 s to enhance conductivity. Two-dimensional wide-angle X-ray diffraction (2D-WAXD) and small-angle X-ray scattering (SAXS) experiments were conducted on a Xeuss 3.0 Discover diffractometer (Cu Kα, 30 W) using an Eiger 2R-1M detector in transmission mode (sample-to-detector distance: 55-1800 mm), with scattering data analyzed via the power-law model\u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:I\\left(q\\right)=B\\bullet\\:{q}^{-df}\\)\u003c/span\u003e\u003c/span\u003e (describing fractal structures) and Guinier\u0026rsquo;s law model\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:I\\left(q\\right)={\\alpha\\:\\bullet\\:e}^{-\\frac{-{q}^{2}{Rg}^{2}}{3}}\\)\u003c/span\u003e\u003c/span\u003e (applicable to small-particle systems).\u003c/p\u003e \u003cp\u003eMolecular dynamics (MD) simulations were conducted using the COMPASSⅢ force field and Forcite module implemented in Materials Studio 2020 package. After energy minimization removing potential bad contact of the simulation box, each system underwent equilibration for 400 ps with periodic boundary conditions applied. Short-range Van der Waals interactions were calculated using an atom-based method, while long-range Coulombic interactions were treated with the Ewald summation technique, applying a cutoff distance of 1.25 \u0026Aring;. The equations of Newton\u0026rsquo;s motion during MD simulation were integrated with a 1-fs timestep. The temperature was controlled by a Nos\u0026eacute;-Hoover thermostat at 298 K and the pressure was regulated using Berendsen barostat at 1 bar with isotropic manner applied. Subsequently, production runs were performed in the NVT ensemble for an additional 400 ps to analyze energy and other properties.\u003c/p\u003e\n\u003ch3\u003ePreparation of HPC-PAA based chiral nematic LCE\u003c/h3\u003e\n\u003cp\u003eIn a typical procedure, 0.6\u0026ndash;0.9 ml AA (monomer), 0.168 ml PEGDA (cross-linker) and 8.83 mg LAP (photoinitiator) were mixed with 6 g HPC powder and 3.12 g deionized water, achieving a final HPC concentration of 60 wt%. The mixture was then centrifuged at 8000 rpm for 15 minutes periodically over 3 days to ensure homogeneity, then poured into a mold and covered with a glass substrate. After resting for 10 minutes to facilitate HPC self-assembly, the sample was exposed to 365 nm UV light (468 mW/cm\u003csup\u003e2\u003c/sup\u003e) for 10 minutes to crosslink and capture the chiral nematic organization. The resulting HPC-PAA hydrogel was subsequently oven-dried at 70\u0026deg;C\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e for 6 hours to yield a structurally stable, optically homogeneous composite. With the HPC concentration fixed, the amounts of AA and PEGDA were varied, with AA comprising 10\u0026ndash;15 wt.% of HPC, PEGDA at 20 wt.% of AA, and the amount of deionized water adjusted to maintain the final HPC concentration of 60 wt.% in the mixture. After the fabrication process, the obtained HPC-PAA composite was immersed in 1 M Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution at 70\u0026deg;C for 90 minutes, leading to the formation of LCE. Control experiments can be done by immersing the HPC-PAA composite in either deionized water or NaCl under the same conditions.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBiocompatibility Assessment of the LCE\u003c/h2\u003e \u003cp\u003eThe as-prepared biocompatible LCE were fabricated by immersing HPC-PAA composites in 1 M NaCl and Na₂SO₄ solutions, respectively. The elastomers were then sectioned into 20 \u0026times; 20 mm\u0026sup2; specimens and incubated in 2 mL of DMEM at 37\u0026deg;C for 24 hours and the cell viability were determined by CCK8 medium containing 10% fetal bovine serum overnight. L929 fibroblasts cell was seeded in 96-well plates at a density of 10,000 per well and cultured in DMEM medium containing 10% fetal bovine serum overnight. 10 \u0026micro;L of each DMEM sample was added into the plate (experimental groups). 10 \u0026micro;L of fresh DMEM was used as control groups. Six parallel replicates were performed to ensure statistical robustness. Following a 1-hour incubation at 37\u0026deg;C, the solutions were removed, and absorbance was measured at 570 nm using a microplate reader (FilterMax F5, Molecular Devices, Shanghai, China). Cell viability was quantified based on the relative growth rate (RGR):\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eWhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{A}}_{\\text{s}}\\)\u003c/span\u003e\u003c/span\u003e, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{A}}_{\\text{b}}\\)\u003c/span\u003e\u003c/span\u003e, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{A}}_{\\text{c}}\\)\u003c/span\u003e\u003c/span\u003e represent the absorbance values of experimental group, blank group and control group, respectively.\u003c/p\u003e\n\u003cp\u003eTo assess cell viability, the cultured cells were aspirated and stained by Calcein and Propidium Iodide. The L929 cell was treated with each group and then incubated with 100 \u0026micro;L medium which contains staining reagent solution in a 96-well plate at 37\u0026deg;C for 30 minutes. Confocal Laser Scanning Microscope (DFC310-FX, Leica Microsystems, Germany) was used to capture and record the results.\u003c/p\u003e\n\u003ch3\u003eLCE Self-healing Assessment\u003c/h3\u003e\n\u003cp\u003eThe as prepared HPC-PAA elastomer, with 20 mm in width, was precisely cut, and the severed surfaces were carefully realigned and brought into contact. Then the attached samples were immersed in a 1 M Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution at 70\u0026deg;C for 30 or 60 minutes to facilitate self-healing. After the designated healing period, the samples were examined for visual integrity and subsequently subjected to further mechanical testing to assess their self-healing performance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLukuan Guo, Jing Sun: Data curation, Formal analysis, Methodology, Writing\u0026ndash;original draft. Xinxin Yan,\u0026nbsp;Xuemei Ge: Investigation; Methodology. Guang Chu: Conceptualization, Supervision, Writing\u0026ndash;Review \u0026amp; Editing. Junlong Song: Writing\u0026ndash;Review \u0026amp; Editing. Jiaqi Guo: Conceptualization, Methodology, Project administration, Supervision, Writing\u0026ndash;review \u0026amp; editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNotes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing financial interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the funding support from National Natural Science Foundation (32371811), Natural Science Foundation of Jiangsu Province for Youth (BK20210622), and Shandong Postdoctoral Science Foundation (SDBX2023039). The authors thank the project of Specially Appointed Professor Plan of Jiangsu Province.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eZheng G\u003cem\u003e, et al.\u003c/em\u003e Recent advances in functional utilisation of environmentally friendly and recyclable high-performance green biocomposites: A review. \u003cem\u003eChinese Chemical Letters\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, 108817 (2024).\u003c/li\u003e\n\u003cli\u003eAjdary R, Tardy BL, Mattos BD, Bai L, Rojas OJ. Plant Nanomaterials and Inspiration from Nature: Water Interactions and Hierarchically Structured Hydrogels. \u003cem\u003eAdv Mater\u003c/em\u003e \u003cstrong\u003e33\u003c/strong\u003e, 2001085 (2021).\u003c/li\u003e\n\u003cli\u003eTang J, Sisler J, Grishkewich N, Tam KC. 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Springer Berlin Heidelberg (2015).\u003c/li\u003e\n\u003cli\u003eWang S\u003cem\u003e, et al.\u003c/em\u003e Coassembling Hydroxypropyl Cellulose into a Chiral Nematic Composite and Patternization with a Photomask and Direct Ink Writing. \u003cem\u003eACS Applied Polymer Materials\u003c/em\u003e \u003cstrong\u003e5\u003c/strong\u003e, 9642-9649 (2023).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6702808/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6702808/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe development of sustainable, high-performance elastomer is an emerging field, driven by the growing demand for eco-friendly materials with multifunctional capabilities that can meet complex performance requirements. Cellulose, as the most abundant and renewable bioresource in nature, pose significant challenges for its use in the design and fabrication of stretchable elastomer. The intrinsic characteristic of cellulose, namely, the intermolecular hydrogen bonding between neighboring linear chain of D-glucose units, hinder processability and limit its mechanical flexibility. In this study, we developed a chiral nematic liquid crystal elastomer mainly composed of plant derived hydroxypropyl cellulose (HPC), in which the mechanical and optical properties were precisely tuned by modulating the intermolecular forces within the HPC complexes through salting-induced Hofmeister effect. The obtained composite exhibits vivid structural color arising from the right-handed chiral nematic architecture, while its elasticity is controlled by the cellulose-water interactions through hydrogen bonds. The HPC-based liquid crystal elastomer shows remarkable mechanochromic behavior with the structural color shifting in response to applied force. This dynamic color changes enable real-time monitoring of mechanical stress, with practical applications in rehabilitation training. Besides, owing to the biocompatible and biodegradable nature of HPC, the resulting liquid crystal elastomer can be fully degraded within 30 days in natural environments. The current work introduces an innovative strategy for the design of sustainable, high-performance devices based on cellulose-derived elastomers, highlighting the potential for eco-friendly and multifunctional applications.\u003c/p\u003e","manuscriptTitle":"Plant Derived Bio-based Liquid Crystal Elastomer with On-demand Mechanochromic Response","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-03 09:20:48","doi":"10.21203/rs.3.rs-6702808/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bbcbebdf-f5ba-4be4-aae6-0bd9532e85c1","owner":[],"postedDate":"June 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":49393923,"name":"Physical sciences/Chemistry/Biochemistry/Biopolymers"},{"id":49393924,"name":"Physical sciences/Materials science/Biomaterials/Bioinspired materials"},{"id":49393925,"name":"Physical sciences/Nanoscience and technology/Nanoscale materials/Molecular self-assembly"},{"id":49393926,"name":"Physical sciences/Optics and photonics/Optical materials and structures/Biomaterials/Bioinspired materials"}],"tags":[],"updatedAt":"2026-04-20T16:20:44+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-03 09:20:48","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6702808","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6702808","identity":"rs-6702808","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}