Efficient Tuning of Conductive Gel Properties via Branch Engineering

Efficient Tuning of Conductive Gel Properties via Branch Engineering | 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 Research Article Efficient Tuning of Conductive Gel Properties via Branch Engineering Pizheng Zhang, Jie Wang, Xiufang Ran, Boao Sun, Zifeng Liu, Bo Qin This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9080935/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Conductive gels are a class of important soft materials with broad application potential in various emerging fields. To better meet the diverse and high-standard demands of modern materials science, it is crucial to carry out modification research on conductive gels. Branching engineering, which takes polymer topological structure as the core regulatory variable, alters the relevant characteristics of molecular chains and regulates the microstructures and macroscopic properties of gels at the molecular scale, providing a feasible approach to solve this problem. In this study, we systematically investigated the effects of branch length and terminal groups on the structure and properties of a novel conductive gel. Specifically, by regulating the hydrogen bonding interactions within the gel network, the thermal stability of the gel was significantly improved, and its ultraviolet (UV) stimulus responsiveness and conductivity were successfully achieved. branching chain structure crown ether supramolecular conductive gel Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Gels are a class of materials composed of a three-dimensional polymer network or a non-fluid colloidal system saturated with liquid. Their porous structure contains numerous voids, which can be filled with specific media to fulfill customized functional requirements [ 1 ]. Among these materials, conductive gels are emerging as exceptional soft materials due to their intrinsic properties, such as conductivity, flexibility, stretchability, and biocompatibility [ 2 – 3 ]. They demonstrate considerable application potential in various fields, including solid-state electrolytes [ 4 ], energy storage devices [ 5 – 6 ], biomedicine [ 7 ], flexible wearable electronics [ 8 – 9 ], and optoelectronic displays [ 10 ]. However, effectively integrating the multidimensional characteristics of gels into a single conductive gel material to meet diverse mechanical and chemical requirements of different applications remains a formidable challenge [ 11 ]. Currently, most studies focus on improving the conductivity and mechanical properties of gels through direct doping or the compositing of multiple functional materials [ 12 – 15 ]. Nevertheless, few studies have explored the relationship between the spatial configuration of the gel network and its performance [ 16 ], and even fewer have investigated the influence of branching chains on the construction and property regulation of gel networks. Existing studies on molecular structure design for polymer semiconductors and flexible wearable materials mainly focus on backbone, branching chain, and end-group engineering [ 17 – 18 ]. Branching chain design was originally used to improve conjugated polymer solubility, and has now evolved into an effective strategy for structural bridging and spatial configuration tuning. Variations in branching chain end-group type and length are key to regulating polymer properties [ 17 , 18 ]. As important functional sites of branching chains, the end-group can enhance material performance through specific interactions between groups [ 19 ], hydrogen bonding [ 20 , 21 ], and other mechanisms. For example, Hu et al. [ 22 ] employed thermal annealing to convert alkyl branching chains of diketopyrrolopyrrole (DPP) polymers into N–H–C = O moieties, introducing abundant hydrogen-bonding sites. These hydrogen bonds maintained the DPP backbone while strengthening intermolecular interactions, thus boosting conductivity and self-healing ability. Additionally, branch length significantly influences structural order, charge transport [ 21 , 22 ], and mechanical properties [ 23 ] of the materials. Kureha et al. [ 24 ] studied the impact of the length of ethylene oxide (EO) side chains on the properties of poly (oligo (ethylene glycol) methyl ether ester) (POEG) gels. Longer EO side chains prevented unexpected entanglement between the poly(methacrylate) backbone chains, leading to enhanced gel stiffness. However, there are few examples of comprehensive studies on the impact of branch length and functional groups on structural properties, particularly in the gel domain. To deeply explore the effects of branch length and terminal groups on the gel properties, we synthesized hydroxy branching chain ligands with different carbon chain lengths (ranging from 2 to 8), ester-based ligands with 6 carbon chain length, and alkyl branching chain gel ligands with a carbon chain length of 6. In our previous work [ 25 ], we studied how the crown ether ring in the ligand interacts with potassium ions through host-guest interactions, forming a transverse one-dimensional linear structure. In this study, we explored the impact of side chains and found that they also affect the construction of the gel network along the longitudinal direction. The branching chain plays a significant role in the construction of the gel network. For ligands with short branched chains (those containing 2 or 3 carbon atoms), no gel formation occurred, whereas stable gel formation was observed when the carbon chain length exceeded 4, among which the hydroxy ligand with 6 carbon atoms exhibited the most stable gelation properties. On the other hand, in the dimension of terminal groups, the introduction of hydroxyl groups enhances hydrogen bonding between gel monomer molecules, which significantly increases the gelation point. Notably, the gel with a six-carbon tail and a terminal hydroxyl group has a gelation point of 82°C. Additionally, we also developed its UV light-responsive function and good electrical conductivity conductivity. 2. Experimental and research 2.1 Synthesis of gel ligands To further investigate the effects of branch length and terminal groups on gel properties, we designed to introduce different branching chains at the NH position of the pyridone structure, and synthesized Hn-L with different carbon chain lengths ranging from 2 to 8, ester-based ligands with a carbon chain length of 6(E6-L), and alkyl branching chain gel ligands with a carbon chain length of 6 (C6-L)via a five-step reaction (Fig. 1 ). According to previous studies [ 25 ], this class of ligands can form a sandwich-like 2:1 ligand complex through the host-guest interaction between the crown ether ring and K⁺, thereby realizing the construction of the one-dimensional (1D) horizontal main chain of the gel. Meanwhile, the influence of the branching chain structure on the gelation behavior and the resulting changes in the gel network structure constitute the focus of this study. 2.2 Optimization of Gel Formation Conditions 2.2.1 The influence of the equivalents of potassium salts on gelation. To further verify the effect of potassium salts on gelation after branching chain modification, we selected the ligand H6-L to fabricate gels with KPF6 of different equivalents (S3.1). The Figure S22 indicates that 1 eq is the binding critical point for gelation, which is also consistent with the binding ratio determined in previous work. [27] It can be observed that within the same time period, the gels with 1 eq and 1.5 eq of potassium salt exhibited a prominent tendency to detach. Only when the equivalent amount of potassium salt reached 2 eq did the gel achieve stability without any detachment tendency. This further demonstrates the effect of potassium salt concentration on gel performance in a straightforward manner. To determine the optimal performance of the gel, thus the gel containing 2 eq of potassium salt was selected for subsequent relevant performance tests. 2.2.2 The Effects of Branching Chain Length on Gelation To comprehensively investigate the effects of carbon chain length on gel performance, ligands with a hydroxyl group as the terminal substituent were selected to fabricate gels with KPF6, and gel precursors with a branching chain length of 2–8 carbon atoms were synthesized(S3.2). From Figure S23 we can find the samples with a carbon chain length of 2 and 3 fail to form gels. This indicates that the carbon chain length exerts an influence on the crosslinking of the gel network. In contrast, previous studies only focused on the interaction between crown ethers and K⁺ for gel formation, without conducting an in-depth exploration of the effect of branching chains on the gel network. In addition, we found that H6 + K + gel exhibits the weakest downward falling trend thus demonstrates the highest stability. We hypothesize that this phenomenon arises from the fact that a carbon chain length of 6 constitutes the optimal distance for intermolecular interactions between the side chain and another molecule, which will be further verified in our subsequent research. 2.2.3 The effect of functional groups in branching chains on gel formation In our previous work [ 25 ], the gel point of the gel sample formed by C8-L with KPF6 was approximately 60℃, which is relatively low. Thus, we introduced hydroxyl groups onto the side chains, aiming to form certain hydrogen bonds via these hydroxyl groups to enhance the gel stability. Simultaneously, we also incorporated hydrophobic ester groups to investigate the effects of different functional groups on the gel properties(S3.3). It was found that the H6 + K + gel sample exhibited the most stable colloidal properties, followed by the alkyl-containing derivative, while the ester-containing derivative showed the poorest stability (Figure S24). We hypothesize that this phenomenon is attributed to the ability of hydroxyl groups to form hydrogen bonds, whereas alkyl and ester groups possess a weaker hydrogen bond-forming capacity. 2.2.4 Comparative Analysis of Gelation Properties Determination of the Gel Point The gel point is defined as the characteristic temperature corresponding to the sol-to-gel transition, and this property of the gel can be characterized via Differential Scanning Calorimetry(DSC) measurements [ 26 ]. Upon one-step uniform heating of the gels from 25℃ to 100℃, we determined the gel points of different gel samples (S3.4 and Figure S25). Further comparative analysis revealed that among the Hn + K + gel samples, H6 + K + exhibited the highest gel point of 82.6℃. Furthermore, in the comparison of different functional groups, we found that hydroxyl groups also exhibited the highest gel point, approximately 10℃ higher than that of alkyl groups (Fig. 2 ). This reflects the enhancement of gel stability by the hydrogen bonds formed after the introduction of hydroxyl groups. In contrast, due to their inherent polarity, ester groups tend to form fewer hydrogen bonds and introduce a certain degree of steric hindrance, thus exhibiting the lowest stability—this is also consistent with the conclusions from the gelation experiments. 2.2.5 Rheological Property Evaluation of Gel Systems Rheological tests enable the characterization of gel formation and viscoelastic properties, thereby facilitating the assessment of gel stability. This work conducted rheological tests on the most excellent-performing H6 + K + gel among all gels, using a 5 cm-diameter parallel plate fixture. Amplitude sweep and frequency sweep were carried out on the sample under ambient temperature and pressure, with its rheological data compared to those of the C8 + K + gel in previous work [ 25 ]. 2.3 Mechanism Analysis of Hydroxyl-Containing Branching Chains Enhancing the Thermal Properties of Gels 2.3.1 FT-IR Characterization FT-IR spectroscopy can detect characteristic absorption peaks of groups (e.g., hydroxyl and amino groups). Upon hydrogen bond formation, the corresponding peaks shift, typically a redshift. Based on this, we performed FT-IR measurements on the acetonitrile solution of H6-L monomer and H6-L gel respectively to investigate hydrogen bonding interactions after gelation. As shown in Figure S26, after gelation, the wavenumber of the hydroxyl peak in H6-L shifted from 3354 to 3330 toward lower wavenumbers, indicating enhanced hydrogen bonding .0interactions of the hydroxyl groups. 2.3.2 2D NMR Spectra for Identifying Hydrogen Bonding Interaction Positions As shown in Fig. 4 a, the NOESY spectrum exhibits interactions between the hydrazone linkage and hydroxyl groups. We hypothesize that hydroxyl groups form hydrogen bonds by approaching the hydrazone linkage from the bottom, which precisely accounts for the failure of gelation in samples with a carbon chain length of 2-their excessively short branching chains cannot achieve longitudinal cross-linking of the gel network with adjacent molecules. To further verify this hypothesis, we performed High-Resolution Mass Spectrometry (HRMS) on the H6-L monomer, identifying the presence of dimers and trimers (Figure S27). This confirms that hydroxyl groups indeed form hydrogen bonds with hydrazone moieties by approaching from the bottom, enabling longitudinal cross-linking. We further compared the ¹H NMR spectra of C8-L, C6-L and H6-L monomers in CDCl₃ solvent, as shown in Figure S28. The NH chemical shifts of both C6-L and C8-L were 12.89; since alkyl branching chains do not induce hydrogen bonding interactions, their acylhydrazone NH shifts were identical. In contrast, the acylhydrazone NH shift of H6-L shifted to 12.86, which is exactly caused by the hydrogen bonding between hydroxyl groups and pyridone carbonyl groups, thus verifying the intermolecular hydrogen bonding model formed by biomolecules. 2.3.3 SEM-Based Comparative Morphological Analysis In contrast, the sample with a carbon chain length of 6 formed a uniformly cross-linked network, which facilitates the resistance of the gel structure to external stimuli, thus endowing it with the most stable properties. In addition, we also compared the SEM images of samples with a carbon chain length of 6 but different functional groups. It was found that the microscopic network structure of the hydroxyl group-based samples was more uniform and tightly connected (Fig. 5 a). However the uniformity and cross-linking degree decreased progressively from the alkyl group to the ester group. This finding also explains why the H6 + K + gel sample exhibited faster gelation kinetics and higher stability. 2.4 Gel Performance Characterization and Applications 2.4.1 Stimuli-responsive properties of gels Using the H6 + K + gel as the research subject, this work investigated its reversible gel-sol transition performance under thermal, acid-base and UV light stimuli. Figure 6 shows that the gel exhibits sensitive and reversible responsiveness to all three types of stimuli. For thermal responsiveness, the H6 + K + gel transforms into a sol within 10 s at 70°C, exhibiting superior thermal stability to the C8 + K + gel (60°C), and reverts to the gel state within 10 s after heat removal. For acid-base responsiveness, the H6 + K + gel turns into a sol within 10 s upon addition of acetic acid, and reverts to gel within 10 s after subsequent addition of triethylamine. For UV responsiveness, leveraging the E/Z photoisomerization of acylhydrazone bonds, the H6 + K + gel was irradiated with a 10 W, 365 nm UV lamp for 5 min in an ice-salt bath. The acylhydrazone bonds in H6 underwent E→Z isomerization, which disrupted the interaction between crown ether rings and K + ions, damaged the gel backbone structure, and thus triggered gel-to-sol transition. After UV irradiation removal, the bonds reverted to the E configuration, enabling reversible reconstruction of the gel network and thereby realizing reversible UV responsiveness (Fig. 6 ). In addition, the UV absorption spectra of all gel samples were measured (Figure S30). All samples showed absorption at approximately 334 nm, further confirming that the photoresponsive property of acylhydrazone bonds is the intrinsic mechanism underlying the gel’s UV-stimuli responsiveness. 2.4.2 Conductive properties of gels As shown in Fig. 7 , all gels exhibited an electrical conductivity of approximately 5.8 mS/cm at 20°C, indicating that their conductivity is independent of side chain types and mainly contributed by free potassium ions in the three-dimensional network and the conjugated structure of the gel backbone. Upon heating to 60°C, most gels collapsed into sol. Driven by structural collapse and intensified ionic mobility at high temperatures, the conductivity of all samples increased significantly compared with that at 20°C. Only the H6 + K + gel maintained a stable structure and retained comparable conductivity, reaching 7.59 mS/cm. This property lays a foundation for its application in electronic soft materials under heating conditions and provides the possibility of temperature-controlled regulation of material conductivity. To more intuitively demonstrate the electrical conductivity of the H6 + K + gel, it was connected to an electrical circuit equipped with an LED bulb (Figure S31). The LED bulb lit up upon connection, indicating that the gel exhibits excellent electrical conductivity. 3. Conclusion In this work, a series of acylhydrazone crown ether ligands with varied carbon chain lengths and terminal branching chains were synthesized, and supramolecular gels were fabricated via crown ether-K + host-guest self-assembly. Systematic investigations revealed that the H6 + K + gel, featuring a 6-carbon chain and hydroxyl terminal group, exhibited the optimal stability, which was attributed to the hydrogen bonding between pendant hydroxyl groups and pyridone carbonyl groups. The H6 + K + gel demonstrated reversible responsiveness to heat, acid-base stimuli and 365 nm UV light. All gels showed a comparable conductivity of ~ 5.8 mS/cm at 20 ℃, independent of branching chain types; notably, only the H6 + K + gel retained its gel state at 60°C with an enhanced conductivity of 7.59 mS/cm. This study provides a novel branching chain modification strategy for conjugated materials, and the prepared photoresponsive supramolecular conductive gels hold promising application potential in photo/thermo-controlled smart materials, conductive soft materials for high-temperature scenarios and varistor materials. Declarations Author Contribution Pizheng Zhang and Jie Wang jointly completed the experimental design, synthesis of target compounds, sorting and analysis of experimental data, as well as the drafting of the initial manuscript. Boao Sun was responsible for the synthesis of partial experimental samples and participated in the FT-IR test and data collection. Xiufang Ran participated in the synthesis of partial experimental samples and assisted in the UV-Vis test. Zifeng Liu was engaged in the retrieval, sorting and induction of relevant literatures. Acknowledgement The author express gratitude to the Chongqing University for infrastructural support. Data Availability The data that support the findings of this study are available from the corresponding author upon request. References Bari, G.A.K.M.R., Jeong, J.H., Barai, H.R.: Conductive Gels for Energy Storage, Conversion, and Generation: Materials Design Strategies, Properties, and Applications. Materials. 17 (10), 2268 (2024). https://doi.org/10.3390/ma17102268 Wei, J., Xiao, P., Chen, T.: Water-Resistant Conductive Gels toward Underwater Wearable Sensing. Adv. 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University","correspondingAuthor":false,"prefix":"","firstName":"Zifeng","middleName":"","lastName":"Liu","suffix":""},{"id":607170675,"identity":"a31c213c-194a-41e7-9b83-1bf638eeac73","order_by":5,"name":"Bo Qin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAs0lEQVRIiWNgGAWjYDACZgY2BoYKCFuCBC1nSNLCANTC2EaKFr7jvMcefJxnJ7vhAPPB2zwMdnkEtUge5ks3nLkt2XjDAbZkax6G5GKCWgwO85hJ8247kLjhAJDBw3AgsYE4LXNAWvi/kaKlAWwLG3FaJA/zmBvOOJZsPPMwm7HlHINkwlr4zp8xe/Chxk6273jzwxtvKuwIa2E4AKEYG5jB7iSoHlkLMYpHwSgYBaNgZAIA7XU5gFasYLQAAAAASUVORK5CYII=","orcid":"","institution":"Chongqing University","correspondingAuthor":true,"prefix":"","firstName":"Bo","middleName":"","lastName":"Qin","suffix":""}],"badges":[],"createdAt":"2026-03-10 08:08:25","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9080935/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9080935/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104788842,"identity":"764139fc-6c44-4145-9740-c25f2ff0f9bd","added_by":"auto","created_at":"2026-03-17 08:26:41","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":94802,"visible":true,"origin":"","legend":"\u003cp\u003eSynthetic routes of \u003cstrong\u003e5a-i\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/888335c1df30e9d4f2da2ef2.jpg"},{"id":104789108,"identity":"5469d936-7116-47cc-8fb9-393dd9df371b","added_by":"auto","created_at":"2026-03-17 08:28:29","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":84172,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of gelation points\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/ac065b1c73ed797ee8e44aec.jpg"},{"id":104788945,"identity":"5a43bcbd-1a98-4241-8e50-a333b203add4","added_by":"auto","created_at":"2026-03-17 08:27:45","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":101538,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Frequency Scan of H6+K\u003csup\u003e+\u003c/sup\u003e Gel (b) Amplitude Scan of H6+K\u003csup\u003e+\u003c/sup\u003e Gel (c) Frequency Scan of C8+K\u003csup\u003e+\u003c/sup\u003e Gel (d) Amplitude Scan of C8+K\u003csup\u003e+\u003c/sup\u003e Gel\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/117b74b202a7321c121a7d12.jpg"},{"id":104788864,"identity":"62cd3e40-94dd-401e-bc51-3fc1812b9f93","added_by":"auto","created_at":"2026-03-17 08:27:06","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":88352,"visible":true,"origin":"","legend":"\u003cp\u003e(a) NOESY spectrum of H6 monomer in DMSO-d6 (b) Schematic diagram of H6 hydrogen bonding interactions\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/bb892f8f40c7292be6ff70c5.jpg"},{"id":104788796,"identity":"1447809c-5bf8-4161-87a9-9ee8a8bee4fb","added_by":"auto","created_at":"2026-03-17 08:26:26","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":141260,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The SEM images of dried samples of H2、H6、C6、E6 after adding K\u003csup\u003e+\u003c/sup\u003e (b) Schematic diagram of the structures of H2、H6、C6、E6\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/ef12f66a76727ce2633111ba.jpg"},{"id":104788863,"identity":"aeb0ffdd-605d-4977-a633-75c819a7b31c","added_by":"auto","created_at":"2026-03-17 08:27:00","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":56393,"visible":true,"origin":"","legend":"\u003cp\u003eGel-Sol Transition of H6+K\u003csup\u003e+\u003c/sup\u003e Gel\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/e39d2629b3269b9518dc33b2.jpg"},{"id":104789570,"identity":"e7191d22-7257-4fda-b498-c8733688307b","added_by":"auto","created_at":"2026-03-17 08:30:14","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":94254,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 6\u003c/strong\u003e (a) UV response mechanism of H6 monomer (b) UV gel-sol transition mechanism of H6+K\u003csup\u003e+\u003c/sup\u003e gel\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/5c643486a9feba0a5ba8f520.jpg"},{"id":104788882,"identity":"80107bc6-9ac5-4c7a-9b02-f3ff043348fe","added_by":"auto","created_at":"2026-03-17 08:27:09","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":99517,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure.7\u003c/strong\u003e Conductivity of Various Gel Samples under 20 °C and 60 °C\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/79c132c24a62604af44d58e3.jpg"},{"id":104790508,"identity":"82c38f6b-33b9-40ae-b433-31d4ef6bf350","added_by":"auto","created_at":"2026-03-17 08:33:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1557594,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/125d893c-fbf7-4684-9df7-2339daaef24f.pdf"},{"id":104789551,"identity":"47f64797-b6fa-4469-a1d3-1f525e4ea6a4","added_by":"auto","created_at":"2026-03-17 08:30:08","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":8610588,"visible":true,"origin":"","legend":"","description":"","filename":"Supportinginformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-9080935/v1/8ec66657ef9b0d21fc57a18b.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Efficient Tuning of Conductive Gel Properties via Branch Engineering","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eGels are a class of materials composed of a three-dimensional polymer network or a non-fluid colloidal system saturated with liquid. Their porous structure contains numerous voids, which can be filled with specific media to fulfill customized functional requirements [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Among these materials, conductive gels are emerging as exceptional soft materials due to their intrinsic properties, such as conductivity, flexibility, stretchability, and biocompatibility [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. They demonstrate considerable application potential in various fields, including solid-state electrolytes [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], energy storage devices [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], biomedicine [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], flexible wearable electronics [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], and optoelectronic displays [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. However, effectively integrating the multidimensional characteristics of gels into a single conductive gel material to meet diverse mechanical and chemical requirements of different applications remains a formidable challenge [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Currently, most studies focus on improving the conductivity and mechanical properties of gels through direct doping or the compositing of multiple functional materials [\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Nevertheless, few studies have explored the relationship between the spatial configuration of the gel network and its performance [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], and even fewer have investigated the influence of branching chains on the construction and property regulation of gel networks.\u003c/p\u003e \u003cp\u003eExisting studies on molecular structure design for polymer semiconductors and flexible wearable materials mainly focus on backbone, branching chain, and end-group engineering [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Branching chain design was originally used to improve conjugated polymer solubility, and has now evolved into an effective strategy for structural bridging and spatial configuration tuning. Variations in branching chain end-group type and length are key to regulating polymer properties [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. As important functional sites of branching chains, the end-group can enhance material performance through specific interactions between groups [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], hydrogen bonding [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], and other mechanisms. For example, Hu et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] employed thermal annealing to convert alkyl branching chains of diketopyrrolopyrrole (DPP) polymers into N\u0026ndash;H\u0026ndash;C\u0026thinsp;=\u0026thinsp;O moieties, introducing abundant hydrogen-bonding sites. These hydrogen bonds maintained the DPP backbone while strengthening intermolecular interactions, thus boosting conductivity and self-healing ability. Additionally, branch length significantly influences structural order, charge transport [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], and mechanical properties [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] of the materials. Kureha et al. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] studied the impact of the length of ethylene oxide (EO) side chains on the properties of poly (oligo (ethylene glycol) methyl ether ester) (POEG) gels. Longer EO side chains prevented unexpected entanglement between the poly(methacrylate) backbone chains, leading to enhanced gel stiffness. However, there are few examples of comprehensive studies on the impact of branch length and functional groups on structural properties, particularly in the gel domain.\u003c/p\u003e \u003cp\u003eTo deeply explore the effects of branch length and terminal groups on the gel properties, we synthesized hydroxy branching chain ligands with different carbon chain lengths (ranging from 2 to 8), ester-based ligands with 6 carbon chain length, and alkyl branching chain gel ligands with a carbon chain length of 6. In our previous work [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], we studied how the crown ether ring in the ligand interacts with potassium ions through host-guest interactions, forming a transverse one-dimensional linear structure.\u003c/p\u003e \u003cp\u003eIn this study, we explored the impact of side chains and found that they also affect the construction of the gel network along the longitudinal direction. The branching chain plays a significant role in the construction of the gel network. For ligands with short branched chains (those containing 2 or 3 carbon atoms), no gel formation occurred, whereas stable gel formation was observed when the carbon chain length exceeded 4, among which the hydroxy ligand with 6 carbon atoms exhibited the most stable gelation properties. On the other hand, in the dimension of terminal groups, the introduction of hydroxyl groups enhances hydrogen bonding between gel monomer molecules, which significantly increases the gelation point. Notably, the gel with a six-carbon tail and a terminal hydroxyl group has a gelation point of 82\u0026deg;C. Additionally, we also developed its UV light-responsive function and good electrical conductivity conductivity.\u003c/p\u003e"},{"header":"2. Experimental and research","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Synthesis of gel ligands\u003c/h2\u003e \u003cp\u003eTo further investigate the effects of branch length and terminal groups on gel properties, we designed to introduce different branching chains at the NH position of the pyridone structure, and synthesized Hn-L with different carbon chain lengths ranging from 2 to 8, ester-based ligands with a carbon chain length of 6(E6-L), and alkyl branching chain gel ligands with a carbon chain length of 6 (C6-L)via a five-step reaction (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAccording to previous studies [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], this class of ligands can form a sandwich-like 2:1 ligand complex through the host-guest interaction between the crown ether ring and K⁺, thereby realizing the construction of the one-dimensional (1D) horizontal main chain of the gel. Meanwhile, the influence of the branching chain structure on the gelation behavior and the resulting changes in the gel network structure constitute the focus of this study.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Optimization of Gel Formation Conditions\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 The influence of the equivalents of potassium salts on gelation.\u003c/h2\u003e \u003cp\u003eTo further verify the effect of potassium salts on gelation after branching chain modification, we selected the ligand H6-L to fabricate gels with KPF6 of different equivalents (S3.1). The Figure S22 indicates that 1 eq is the binding critical point for gelation, which is also consistent with the binding ratio determined in previous work. [27] It can be observed that within the same time period, the gels with 1 eq and 1.5 eq of potassium salt exhibited a prominent tendency to detach. Only when the equivalent amount of potassium salt reached 2 eq did the gel achieve stability without any detachment tendency. This further demonstrates the effect of potassium salt concentration on gel performance in a straightforward manner. To determine the optimal performance of the gel, thus the gel containing 2 eq of potassium salt was selected for subsequent relevant performance tests.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2 The Effects of Branching Chain Length on Gelation\u003c/h2\u003e \u003cp\u003eTo comprehensively investigate the effects of carbon chain length on gel performance, ligands with a hydroxyl group as the terminal substituent were selected to fabricate gels with KPF6, and gel precursors with a branching chain length of 2\u0026ndash;8 carbon atoms were synthesized(S3.2). From Figure S23 we can find the samples with a carbon chain length of 2 and 3 fail to form gels. This indicates that the carbon chain length exerts an influence on the crosslinking of the gel network. In contrast, previous studies only focused on the interaction between crown ethers and K⁺ for gel formation, without conducting an in-depth exploration of the effect of branching chains on the gel network. In addition, we found that H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel exhibits the weakest downward falling trend thus demonstrates the highest stability. We hypothesize that this phenomenon arises from the fact that a carbon chain length of 6 constitutes the optimal distance for intermolecular interactions between the side chain and another molecule, which will be further verified in our subsequent research.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.2.3 The effect of functional groups in branching chains on gel formation\u003c/h2\u003e \u003cp\u003eIn our previous work [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], the gel point of the gel sample formed by C8-L with KPF6 was approximately 60℃, which is relatively low. Thus, we introduced hydroxyl groups onto the side chains, aiming to form certain hydrogen bonds via these hydroxyl groups to enhance the gel stability. Simultaneously, we also incorporated hydrophobic ester groups to investigate the effects of different functional groups on the gel properties(S3.3). It was found that the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel sample exhibited the most stable colloidal properties, followed by the alkyl-containing derivative, while the ester-containing derivative showed the poorest stability (Figure S24). We hypothesize that this phenomenon is attributed to the ability of hydroxyl groups to form hydrogen bonds, whereas alkyl and ester groups possess a weaker hydrogen bond-forming capacity.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.2.4 Comparative Analysis of Gelation Properties Determination of the Gel Point\u003c/h2\u003e \u003cp\u003eThe gel point is defined as the characteristic temperature corresponding to the sol-to-gel transition, and this property of the gel can be characterized via Differential Scanning Calorimetry(DSC) measurements [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Upon one-step uniform heating of the gels from 25℃ to 100℃, we determined the gel points of different gel samples (S3.4 and Figure S25). Further comparative analysis revealed that among the Hn\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel samples, H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e exhibited the highest gel point of 82.6℃. Furthermore, in the comparison of different functional groups, we found that hydroxyl groups also exhibited the highest gel point, approximately 10℃ higher than that of alkyl groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). This reflects the enhancement of gel stability by the hydrogen bonds formed after the introduction of hydroxyl groups. In contrast, due to their inherent polarity, ester groups tend to form fewer hydrogen bonds and introduce a certain degree of steric hindrance, thus exhibiting the lowest stability\u0026mdash;this is also consistent with the conclusions from the gelation experiments.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.2.5 Rheological Property Evaluation of Gel Systems\u003c/h2\u003e \u003cp\u003eRheological tests enable the characterization of gel formation and viscoelastic properties, thereby facilitating the assessment of gel stability. This work conducted rheological tests on the most excellent-performing H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel among all gels, using a 5 cm-diameter parallel plate fixture. Amplitude sweep and frequency sweep were carried out on the sample under ambient temperature and pressure, with its rheological data compared to those of the C8\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel in previous work [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Mechanism Analysis of Hydroxyl-Containing Branching Chains Enhancing the Thermal Properties of Gels\u003c/h2\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 FT-IR Characterization\u003c/h2\u003e \u003cp\u003eFT-IR spectroscopy can detect characteristic absorption peaks of groups (e.g., hydroxyl and amino groups). Upon hydrogen bond formation, the corresponding peaks shift, typically a redshift. Based on this, we performed FT-IR measurements on the acetonitrile solution of H6-L monomer and H6-L gel respectively to investigate hydrogen bonding interactions after gelation. As shown in Figure S26, after gelation, the wavenumber of the hydroxyl peak in H6-L shifted from 3354 to 3330 toward lower wavenumbers, indicating enhanced hydrogen bonding .0interactions of the hydroxyl groups.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 2D NMR Spectra for Identifying Hydrogen Bonding Interaction Positions\u003c/h2\u003e \u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea, the NOESY spectrum exhibits interactions between the hydrazone linkage and hydroxyl groups. We hypothesize that hydroxyl groups form hydrogen bonds by approaching the hydrazone linkage from the bottom, which precisely accounts for the failure of gelation in samples with a carbon chain length of 2-their excessively short branching chains cannot achieve longitudinal cross-linking of the gel network with adjacent molecules.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo further verify this hypothesis, we performed High-Resolution Mass Spectrometry (HRMS) on the H6-L monomer, identifying the presence of dimers and trimers (Figure S27). This confirms that hydroxyl groups indeed form hydrogen bonds with hydrazone moieties by approaching from the bottom, enabling longitudinal cross-linking. We further compared the \u0026sup1;H NMR spectra of C8-L, C6-L and H6-L monomers in CDCl₃ solvent, as shown in Figure S28. The NH chemical shifts of both C6-L and C8-L were 12.89; since alkyl branching chains do not induce hydrogen bonding interactions, their acylhydrazone NH shifts were identical. In contrast, the acylhydrazone NH shift of H6-L shifted to 12.86, which is exactly caused by the hydrogen bonding between hydroxyl groups and pyridone carbonyl groups, thus verifying the intermolecular hydrogen bonding model formed by biomolecules.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e2.3.3 SEM-Based Comparative Morphological Analysis\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn contrast, the sample with a carbon chain length of 6 formed a uniformly cross-linked network, which facilitates the resistance of the gel structure to external stimuli, thus endowing it with the most stable properties. In addition, we also compared the SEM images of samples with a carbon chain length of 6 but different functional groups. It was found that the microscopic network structure of the hydroxyl group-based samples was more uniform and tightly connected (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). However the uniformity and cross-linking degree decreased progressively from the alkyl group to the ester group. This finding also explains why the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel sample exhibited faster gelation kinetics and higher stability.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Gel Performance Characterization and Applications\u003c/h2\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e2.4.1 Stimuli-responsive properties of gels\u003c/h2\u003e \u003cp\u003eUsing the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel as the research subject, this work investigated its reversible gel-sol transition performance under thermal, acid-base and UV light stimuli. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003e shows that the gel exhibits sensitive and reversible responsiveness to all three types of stimuli.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFor thermal responsiveness, the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel transforms into a sol within 10 s at 70\u0026deg;C, exhibiting superior thermal stability to the C8\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel (60\u0026deg;C), and reverts to the gel state within 10 s after heat removal. For acid-base responsiveness, the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel turns into a sol within 10 s upon addition of acetic acid, and reverts to gel within 10 s after subsequent addition of triethylamine.\u003c/p\u003e \u003cp\u003eFor UV responsiveness, leveraging the E/Z photoisomerization of acylhydrazone bonds, the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel was irradiated with a 10 W, 365 nm UV lamp for 5 min in an ice-salt bath. The acylhydrazone bonds in H6 underwent E\u0026rarr;Z isomerization, which disrupted the interaction between crown ether rings and K\u003csup\u003e+\u003c/sup\u003e ions, damaged the gel backbone structure, and thus triggered gel-to-sol transition. After UV irradiation removal, the bonds reverted to the E configuration, enabling reversible reconstruction of the gel network and thereby realizing reversible UV responsiveness (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003e). In addition, the UV absorption spectra of all gel samples were measured (Figure S30). All samples showed absorption at approximately 334 nm, further confirming that the photoresponsive property of acylhydrazone bonds is the intrinsic mechanism underlying the gel\u0026rsquo;s UV-stimuli responsiveness.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e2.4.2 Conductive properties of gels\u003c/h2\u003e \u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e7\u003c/span\u003e, all gels exhibited an electrical conductivity of approximately 5.8 mS/cm at 20\u0026deg;C, indicating that their conductivity is independent of side chain types and mainly contributed by free potassium ions in the three-dimensional network and the conjugated structure of the gel backbone. Upon heating to 60\u0026deg;C, most gels collapsed into sol. Driven by structural collapse and intensified ionic mobility at high temperatures, the conductivity of all samples increased significantly compared with that at 20\u0026deg;C. Only the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel maintained a stable structure and retained comparable conductivity, reaching 7.59 mS/cm. This property lays a foundation for its application in electronic soft materials under heating conditions and provides the possibility of temperature-controlled regulation of material conductivity.\u003c/p\u003e \u003cp\u003eTo more intuitively demonstrate the electrical conductivity of the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel, it was connected to an electrical circuit equipped with an LED bulb (Figure S31). The LED bulb lit up upon connection, indicating that the gel exhibits excellent electrical conductivity.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Conclusion","content":"\u003cp\u003eIn this work, a series of acylhydrazone crown ether ligands with varied carbon chain lengths and terminal branching chains were synthesized, and supramolecular gels were fabricated via crown ether-K\u003csup\u003e+\u003c/sup\u003e host-guest self-assembly. Systematic investigations revealed that the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel, featuring a 6-carbon chain and hydroxyl terminal group, exhibited the optimal stability, which was attributed to the hydrogen bonding between pendant hydroxyl groups and pyridone carbonyl groups. The H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel demonstrated reversible responsiveness to heat, acid-base stimuli and 365 nm UV light. All gels showed a comparable conductivity of ~\u0026thinsp;5.8 mS/cm at 20 ℃, independent of branching chain types; notably, only the H6\u0026thinsp;+\u0026thinsp;K\u003csup\u003e+\u003c/sup\u003e gel retained its gel state at 60\u0026deg;C with an enhanced conductivity of 7.59 mS/cm. This study provides a novel branching chain modification strategy for conjugated materials, and the prepared photoresponsive supramolecular conductive gels hold promising application potential in photo/thermo-controlled smart materials, conductive soft materials for high-temperature scenarios and varistor materials.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003ePizheng Zhang and Jie Wang jointly completed the experimental design, synthesis of target compounds, sorting and analysis of experimental data, as well as the drafting of the initial manuscript. Boao Sun was responsible for the synthesis of partial experimental samples and participated in the FT-IR test and data collection. Xiufang Ran participated in the synthesis of partial experimental samples and assisted in the UV-Vis test. Zifeng Liu was engaged in the retrieval, sorting and induction of relevant literatures.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe author express gratitude to the Chongqing University for infrastructural support.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBari, G.A.K.M.R., Jeong, J.H., Barai, H.R.: Conductive Gels for Energy Storage, Conversion, and Generation: Materials Design Strategies, Properties, and Applications. 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Astronomy. \u003cb\u003e68\u003c/b\u003e(6) (2024). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11433-024-2547-3\u003c/span\u003e\u003cspan address=\"10.1007/s11433-024-2547-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-inclusion-phenomena-and-macrocyclic-chemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jiph","sideBox":"Learn more about [Journal of Inclusion Phenomena and Macrocyclic Chemistry](http://link.springer.com/journal/10847)","snPcode":"10847","submissionUrl":"https://submission.nature.com/new-submission/10847/3","title":"Journal of Inclusion Phenomena and Macrocyclic Chemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"branching chain structure, crown ether, supramolecular, conductive gel","lastPublishedDoi":"10.21203/rs.3.rs-9080935/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9080935/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eConductive gels are a class of important soft materials with broad application potential in various emerging fields. To better meet the diverse and high-standard demands of modern materials science, it is crucial to carry out modification research on conductive gels. Branching engineering, which takes polymer topological structure as the core regulatory variable, alters the relevant characteristics of molecular chains and regulates the microstructures and macroscopic properties of gels at the molecular scale, providing a feasible approach to solve this problem. In this study, we systematically investigated the effects of branch length and terminal groups on the structure and properties of a novel conductive gel. Specifically, by regulating the hydrogen bonding interactions within the gel network, the thermal stability of the gel was significantly improved, and its ultraviolet (UV) stimulus responsiveness and conductivity were successfully achieved.\u003c/p\u003e","manuscriptTitle":"Efficient Tuning of Conductive Gel Properties via Branch Engineering","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-17 08:11:13","doi":"10.21203/rs.3.rs-9080935/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-31T06:05:19+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-31T05:53:31+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-26T10:21:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"192220429939585476203623509467867330233","date":"2026-03-17T23:45:40+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"21766500013591217302579977091459922166","date":"2026-03-17T08:12:08+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-14T03:46:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"166807214200506727769179565587251293562","date":"2026-03-13T22:13:37+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-12T09:12:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-12T08:29:19+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-12T08:28:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Inclusion Phenomena and Macrocyclic Chemistry","date":"2026-03-10T07:57:25+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-inclusion-phenomena-and-macrocyclic-chemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jiph","sideBox":"Learn more about [Journal of Inclusion Phenomena and Macrocyclic Chemistry](http://link.springer.com/journal/10847)","snPcode":"10847","submissionUrl":"https://submission.nature.com/new-submission/10847/3","title":"Journal of Inclusion Phenomena and Macrocyclic Chemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"6f067175-629c-446f-9a63-de35fcbf41b2","owner":[],"postedDate":"March 17th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T16:44:06+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-17 08:11:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9080935","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9080935","identity":"rs-9080935","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}