A Wearable Electronic Based on Capacitive Flexible Pressure Sensor for Running Motion Monitoring

A Wearable Electronic Based on Capacitive Flexible Pressure Sensor for Running Motion Monitoring | 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 A Wearable Electronic Based on Capacitive Flexible Pressure Sensor for Running Motion Monitoring Xiaoming Chang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2298137/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Mar, 2023 Read the published version in Discover Nano → Version 1 posted 8 You are reading this latest preprint version Abstract The flexible pressure sensor is expected to be applied in the new generation of sports wearable electronic devices. Developing flexible pressure sensors with a wide linear range and great sensitivity, however, remains a significant barrier. In this work, we propose a hybrid conductive elastomeric film oxide-based material with a concave-shape micro-patterned array (P-HCF) on the surface that sustainably shows the necessary sensing qualities. To enhance sensing range and sensitivity, one-dimensional carbon fibers (CF) and two-dimensional MXene (MX) are incorporated into the polydimethylsiloxane (PDMS) matrix to form a three-dimensional conductive network. Micro-patterns with a curved shape in P-HCFs are designed to resemble a human fingerprint and were able to linear sensitivity across the sensing range by controlling the pressure distribution inside the material. Besides, the sensitivity of P-HCF pressure sensor can reach 31.92 kPa − 1 , and meanwhile, the linear band of P-HCF pressure sensor can arrive at 24 Pa − 720 kPa, which makes it a good choice for sports monitoring. The designed pressure sensor can be used to monitor the foot pressure during running. By analyzing the gait information during running, it can provide data support and strategy improvement for running. This new dual working mode pressure P-HCF sensor will provide a new way for the development of intelligent sports. Flexible pressure sensor low-cost high linear sensitivity wide detection range Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction The flexible pressure sensor is mainly based on the piezoresistive effect and pressure-capacitance effect to convert the pressure received by the device into the resistance or capacitance change of the device to realize the pressure sensing [ 1 , 2 ]. Therefore, flexible pressure sensing technology is one of the key technologies of intelligent wearable devices, and the development of this technology promotes the development of wearable devices [ 3 ]. The flexible wearable pressure sensing device is mainly used for health detection and motion detection of the human body, and realize the transformation from the human disease treatment mode to the disease prevention mode [ 4 ]. For human health detection and motion detection, it mainly detects and analyzes micro pressure, such as pulse pressure, blood pressure, intraocular pressure, muscle movement and heart rate [ 5 ]. Because of rapid improvements in functional materials, flexible sensors, and integrated power systems, there has been a surge in interest in wearable electronic gadgets that can monitor and diagnose individual health conditions in real time [ 6 ]. Flexible pressure-sensitive devices have continued to garner interest in the disciplines of prosthetics, health monitoring, and robotics. Depending on the sensing material and mechanism, flexible pressure sensors are categorized as resistive, capacitive, piezoelectric, or optical [ 7 – 9 ]. Among these pressure sensors, resistive pressure sensors are preferred owing to their simple readout mechanism and cost benefits [ 10 ]. Resistive pressure sensors can convert the pressure received into the change of its own resistance, thus realizing the pressure sensing. Generally, engraving process is required to prepare materials with micro nano surface structure. Laser engraving uses advanced laser technology for processing, which belongs to non-contact processing, which avoids scratching the workpiece and achieves engraving, cutting and polishing at the same time. However, traditional mechanical engraving must be in contact with the workpiece, and the workpiece needs to be fixed, which will scratch the workpiece and cause waste of materials. Laser engraving has low energy consumption, no noise and no pollution, which is an energy-saving and environmental protection processing method. However, traditional engraving methods cause noise pollution and require large energy consumption [ 11 ]. Extensive research was undertaken in this study to broaden the detection band and improve the sensitivity for practical application. Numerous successful ways involving novel materials and better architectures were used to increase pressure sensitivity [ 12 , 13 ]. Sun et al. have presented a conductive graphite/polydimethylsiloxane (G/PDMS) foam sheet with a stratified surface microstructure that exhibits a 245 kPa -1 sensitivity [ 14 ]. Numerous materials have been researched for use in pressure sensors, including conducting polymers, graphite, and nanomaterials such as carbon nanotubes (CNTs), graphite, and carbon nanofibers (CF) [ 15 – 22 ]. Additionally, degradation efficiency may be enhanced by developing microtomes and microcones on the surface of the material and by generating microscopic and nanoscale micropores inside the material [ 23 , 24 ]. However, when subjected to high pressures, the material's compressibility declines, resulting in saturation of the number of conducting routes and contact areas in pressure-resistant and contact-type components, resulting in lower sensitivity and irregular response. Consequently, flexible sensors have historically struggled to achieve acceptable sensitivity in the high voltage range [ 25 ]. A sensor's linear sensitivity is defined as the relationship between its output signal and applied load. Pressure sensors in practical applications must work in the linear sensitivity range, which maximizes cost-effectiveness and eliminates the need for further signal processing to receive the correct information [ 26 – 28 ]. Flexible pressure sensors, on the other hand, can be easily integrated with existing signal conditioning systems on the market, which means they have more market potential in industries like artificial intelligence, healthcare, and more. Nonetheless, there are few papers that describe sensors with linear sensitivity around the entire spectral resolution [ 29 ]. Researchers are continuing to work on extending the band and responsiveness of linear sensing. Cho et al., for example, developed a surface using reduced graphene oxide (rGO) and an array of PDMS microdome structures [ 30 ]. The skin has a sensitivity of 8.5 kPa -1 . Wong et al. transformed a stiff non-conductive bulk material into a flexible conductive carbon/silicon composite for use as a sensing material, achieving 10.7 kPa -1 across a broad pressure range (up to 100 kPa) [ 31 ]. Yang et al. recently revealed a pressure sensor with a layered microstructure with an even better sense of 15.4 kPa -1 across a broad linear range of over 200 kPa [ 32 ]. Even though comparative research has yielded more favorable findings, they continue to fall short of meeting the criteria of actual applications in the high-pressure range. To expand the application's scope, it is critical to retain a high level of sensitivity whilst expanding the linear detection range. Here, we propose a hybrid conductive elastomeric film oxide-based material with a concave-shape micro-patterned array (P-HCF) on the surface that sustainably shows the necessary sensing qualities with an excellent linear sensitivity of 31.92 kPa -1 throughout a wide pressure range of 24 Pa to 720 kPa, as well as the ability to sense pressure changes in real time. In this design, PDMS acts as a flexible dielectric in the P-HCF flexible pressure sensor device. When the device is subjected to pressure, the PDMS layer will deform and then cause the pressure device to generate different sensing signal. MXene (MX) can be used as adsorbent due to its unique layered structure, high specific surface area, excellent surface hydrophilicity and rich active sites. The one-dimensional carbon fibers (CF) is introduced into PDMS as a conductive material to enhance its conductivity. As PDMS is hydrophobic, MX needs to be added as adsorbent to fuse CF and PDMS. Compared with the previous sensor materials, we introduced MS into the dielectric elastomer of the sensor, which greatly enhanced the distribution uniformity of conductive materials inside the dielectric elastomer because MS has good adhesion. Unlike conventional flexible detectors, which rely on changes in surface structure to achieve linear sensitivity, this sensing material starts from the surface micro-nano texture characteristics by forming a micro-nano hybrid framework from a multidimensional carbon material in P-HCF by forming a concave-shape micro-pattern that mimics the structure of a human fingerprint. From a macro viewpoint, the array provides multi-step sensing as well. According to the results, the pressure sensor works very well and has the potential for running motion monitoring. 2. Materials And Methods 2.1 Preparation of P-HCF film The P-HCF was fabricated by molding the liquid mixture of conductive elastomers on templates. CFs (8 m diameter, 10 to 100 m length) (400 mesh, Haotian Nano Technology Company) and PDMS (Dow Corning Sylgard 184; the weight ratio of base to curing agent was 10:1) were mixed by a planetary centrifugal mixer. Following that, MS (CCI, Jujo Chemical Co., Ltd. Shenzhen, China) was added to the CFs/PDMS and mixed for 3 hours at 400 rpm using an overhead stirrer (IKA, RW20). As shown in Fig. 1 (a1-a3), the conductive elastomer was bladed onto patterned quartz templates, which were engraved by laser flash (Speedy 360, 60 W) based on programmable patterning with different spacings and depths. The spacings of micro-patterns were 200 µm, 300 µm, and 400 µm; and the depths were 25 µm, 55 µm, 80 µm and 110 µm. The HCF film containing micropatterns were evaporated to dryness in a vacuum oven, cured completely at 100°C, and then peeled away from the template. 2.2 Characterization of P-HCF pressure sensor. The square P-HCF is adhered to the bottom copper laminate electrode using conductive silver glue with the patterned surface facing up. Then, the elastomer top is covered with copper foil to form the pressure sensor. The electrical responses of the sensors were measured by using the mechanical performance testing system (MTS E43.104) and a digital source meter (Keysight B2902A). The applied voltage for measurements of all electrical properties was 0.05 V DC. The curves of pulse monitoring and pressure array were acquired by source meter and electrochemical workstation (Metrohm, M204), respectively. 3. Results And Discussion Conductive elastomeric films comprising micro-and nano-hybrid carbon materials with curved concave-shape micro patterned arrays (P-HCFs) can be generated simply and reliably, as seen in Fig. 1 (a). Figure 1 (a4) shows the picture of P-HCF device. Besides, Fig. 1 (b) illustrates the layout of the flexible pressure sensing element: Between two copper electrodes composed of copper-clad plates, P-HCF is sandwiched. The pressure sensor's fundamental operation is shown in Fig. 1 (c). The external pressure changed the contact area between the concave-shape micro-patterned array on the surface and the upper electrode, leading to the decrease in contact resistance. The conductive electrode is copper foil, which is mainly used as two plates of capacitance to conduct the capacitance change of the pressure sensor, meanwhile, the contact resistance formed between copper electrode and P-HCF film is also an important factor of feedback pressure. Correspondingly, the total current of P-HCF sensor rose with the increase in applied pressure. Moreover, the photograph of the P-HCF pressure sensor is illustrated in Fig. 1 (d). To show the influence of curved microstructure height on the sensitivity and linear band of flexible pressure sensors, four distinct P-HCFs (P0.8-HCF, P1-HCF, P1.2-HCF, and P1.4-HCF) with varying pattern heights were produced while maintaining a pattern spacing and size of 2 mm, as shown in Fig. 2 (a). When applying pressure to the pliable pressure sensor shown in Fig. 2 (b), the sensor's performance is demonstrated. The pressure sensor's sensitivity (S) is described as S= (ΔI/I)/ΔP where ΔI and ΔP note the measured current and pressure changes, respectively, and I denotes the starting current without load. According to the data, as the height of the projectionettes increases, the standardized change in current increases as well (ΔI/I) eventually approaches a linear relationship with the applied pressure across the whole range of 24 Pa to 720 kPa, as shown in Fig.S1 of Supporting Information. Furthermore, the working mechanism of P-HCF pressure sensor is composed of two components: contact resistance (Rc) and film resistance (Rf), as illustrated in Fig. 2 (c). In detail, different pressures will lead to different degrees of deformation of P-HCF pressure sensor. Meanwhile, the distance between CFs and carbon nanoparticles (CNPs) inside P-HCF reduced, resulting on a sharp increase in conductive paths consisting of the physical contact and tunneling effect. As shown in Fig. 2 (d), when the applied pressure grows, the sensor's contact surface will also increase. An electron tunnel junction is formed by sandwiching a thin insulating layer between two metal conductors. It is found that electrons can pass through the tunnel junction, that is, electrons can pass through the insulating layer, which is the tunnel effect. Contact effect is an electrical effect caused by two different materials when they are in contact, which is different from that when they are not in contact and exist independently. As the pressure load increases, the change in Rf due to tunneling and contact effects between the internal conducting filler and the body block caused by pattern deformation progressively rises, increasing the sensor's sensitivity in conjunction with Rc. Until the pattern becomes flat, the change in resistance is primarily determined by the Rf caused by the compressive deformation. As the micropattern's height grows, the process of micropattern to flatten the bulk film takes more time and changes shape more, as shown in Fig. 2 (f). As a consequence, the P1-HCF sensor's sensitivity diminishes and tends to saturate at high pressure, while sensors with micro-patterns of various heights exhibit essentially linear sensitivity over the entire detecting range, as shown in Fig. 2 (b). Additionally, the P1-HCF sensor has a high linear test range of 24 Pa to 720 kPa. This suggests that with a sufficiently complex micro-pattern design, the conductive material compensates for the contacts' saturation effect as the pressure rises, allowing for a broad linear detection range. The compressibility of the pressure sensor rises with increasing spacing because the efficient Young's modulus of the micropattern decreases at the same pressure [ 36 ]. Enhanced micropattern distortion results in a greater contact area and hence extreme susceptibility. However, micropatterns with a relatively large spacing flatten first, and the sensor's sensitivity drops as pressure increases, resulting in a loss of linearity over the whole sensitivity range. On the other hand, it was discovered that sensors with densely separated micropatterns display linear sensitivity across a large sensing area owing to the synergistic impact of contact resistance and film resistance formed during sensing. In the end, the best material to use for a pressure sensor was P1-HCF with a pitch and size of 2 mm [ 37 ]. Compared to previous work [ 15 , 33 , 34 ], the pressure sensor we designed can provide larger pressure test range, but the sensing sensitivity is still limited. The P1-HCF sensor's current-voltage (I-V) curve was tested at various pressure levels ranging from − 3.6 Vto 3.6 V. We observed a clear linear connection and a consistent response, showing that the ohmic properties are stable (Fig. 3 a). The resistance (slope of the curve) reduces proportionately as the applied load rises. To determine the sensor's detection limit (LOD), the present response to stress was established by the following: inserting and lowering a 0.24 g, demonstrating that the sensor is capable of tracking minute pressure fluctuations up to 24 Pa, as seen in Fig. 3 (b). The inset shows the sensor's immediate sensing reaction time (40 ms) and recovery time (20 ms), indicating that the sensor is fast and equivalent to human skin pressure when exposed to external pressure. As present in Fig. 3 (c), the sensor is capable of achieving rapid and linear current changes across a modest pressure range. It is worth noticing that the response signal exhibits a strong linear association with the pressure level as the pressure increases in the high-pressure range (120 ~ 720 kPa), as shown in Fig. 3 (d). The P1-HCF sensor's response at varied compression frequencies with a constant pressure load of 240 kPa is shown in Fig. 3 (e). The pressure sensor is shown to react frequently at various compression frequencies. Furthermore, the reliability test and reversibility test of pressure sensor device performance are shown in Fig. S2 and Fig. S3 of Supporting Information. From the results, the pressure sensor device has good stability. To assess the possibility of pressure sensors being used in the diagnosis of cardiovascular illnesses, sensors were worn on the wrist, and the arterial pulse was measured in real-time, as shown in Fig. 4 (a). A pulse rate of 70 beats per minute was measured here, which is the rate of a healthy adult [ 38 ]. The usual arterial waveforms such as shock wave (P 1 ), tidal wave (P 2 ), and diastolic wave (P 3 ) may be recognized without signal amplification or post-processing. Parkinson's disease (PD) is a neurodegenerative illness that is most often diagnosed in middle-aged and older adults, and muscular stiffness is a common symptom of PD patients. Passive motor resistance in flexors and extensors is a common complaint throughout the range of action. Parkinson's patients mainly show static tremor, slowing down and muscle rigidity. Their gait has certain characteristics, mainly showing flustered gait. With the progress of the disease, their gait abnormalities become more obvious. Muscle stiffness is determined in clinical practice by passive limb movement at the joint. Figure 4 (b) depicts a patient's simulated muscular resistance during passive motion with the sensor connected to the biceps muscle, and depicts the accompanying current changes, suggesting that the P 1 -HCF sensor has potential application value in detecting Parkinson's disease. Additionally, the spatial distribution and pressure values may be seen by including a flexible pressure sensor in the sensing array. Figure 4 (c1-c2) illustrates a 4*4-telescopic pressure sensor array comprised of a P1-HCF sensor and a flexible telescopic circuit that fits inside a hemispherical mold, illustrating that telescopic sensing arrays may be adapted to complicated surfaces in real applications. 3D mapped pictures show pressure values and locations on fingers and palms by height and position, as shown in Fig. 4 (d1-d3). Sensors now pick up on the distribution of pressure and rough outline of objects. To monitor plantar pressure effectively, linear sensing capacity across a wide range of up to several hundred kilopascals is required, as is high sensitivity. As a result, we designed a flexible smart insole with 16 working units located at the toes, forefoot, lateral, and rearfoot, as shown in Fig. 5 (a). The foot pressure distribution of a person weighing 60 kg in a standing posture is shown in Fig. 5 (b). The flexible sensors' broad linearity and excellent sensitivity enable them to gather pressure correctly at each spot. Additionally, the pressure distribution changes during running motion were rebuilt using sixteen consecutive sensors. Interactions between humans and devices, known as human-machine interfaces, are critical components of AI. They have already been implemented in a variety of ways, including embedded platforms in wearable devices such as smartwatch and garments as well as in wristbands, keypads, and microphones. As illustrated in Fig. 5 (c), a flexible pressure sensor-based human-machine interface was produced by connecting a sensing device to the fingers of a textile glove. Two layers of flexible circuits (top and bottom) and P1-HCF were used to construct the sensing device. The output curves may depict various hand movements by combining the on/off and amplitude of the five signals provided by the fingers, as shown in Fig. 5 (d). Additionally, the length and regularity of the signals may be set using Morse code, which are determined by the duration and intensity of thumb bending, as shown in Fig. 5 (e). 4. Conclusions In conclusion, a flexible P-HCF pressure sensor was reported. The multi-step sensing technique enables an extensive dynamic range and great linear sensitivity. The sensing material P-HCF enables the fabrication of the hybrid structured conductive films with concave-shape micro-patterned arrays. 1D CF and 2D MX are used as conductive fillers in PDMS, resulting in a multi-step sensing structure at the microscale network. Filler substrate elastomeric materials have a greatly improved detection range and responsiveness as a result of this improvement. Besides, the sensitivity of P-HCF pressure sensor can reach 31.92 kPa -1 , and meanwhile, the linear band of P-HCF pressure sensor can arrive at 24 Pa − 720 kPa, which makes it a good choice for pressure testing applications. This sensor may be used to detect human pulses and aid in the diagnosis of Parkinson's disease. Simultaneously, it may be useful for monitoring human gait and determining the distribution of foot pressure. This research combines multifunctional material technology with flexible sensing technology, which provides a new idea for the running motion monitoring. Declarations Acknowledgements Not applicable. Authors’ contributions Conceptualization, Xiaoming Chang; formal analysis, Xiaoming Chang; writing-original draft preparation, Xiaoming Chang; writing-review and editing, Xiaoming Chang; visualization, Xiaoming Chang; supervision, Xiaoming Chang. All authors have read and agreed to the published version of the manuscript. Funding Not applicable. Availability of data and materials All data and materials are available without restrictions. Competing interests The authors declare that they have no competing interests. Consent for publication Not applicable. Ethics approval and consent to participate Not applicable. References Shi J, Wang L, Dai Z, et al. Multiscale hierarchical design of a flexible piezoresistive pressure sensor with high sensitivity and wide linearity range[J]. Small, 2018, 14(27): 1800819. Li R, Zhou Q, Bi Y, et al. Research progress of flexible capacitive pressure sensor for sensitivity enhancement approaches[J]. Sensors and Actuators A: Physical, 2021, 321: 112425. Zhang Y, Gong M, Wan P. MXene hydrogel for wearable electronics[J]. Matter, 2021, 4(8): 2655–2658. Li N, Peng J, Ong W J, et al. MXenes: an emerging platform for wearable electronics and looking beyond[J]. Matter, 2021, 4(2): 377–407. Wan D, Yang J, Cui X, et al. Human body-based self-powered wearable electronics for promoting wound healing driven by biomechanical motions[J]. Nano Energy, 2021, 89: 106465. Gates B D. Flexible electronics[J]. Science, 2009, 323(5921): 1566–1567. Gao W, Ota H, Kiriya D, et al. Flexible electronics toward wearable sensing[J]. Accounts of chemical research, 2019, 52(3): 523–533. Sun Y, Rogers J A. Inorganic semiconductors for flexible electronics[J]. Advanced materials, 2007, 19(15): 1897–1916. Russo A, Ahn B Y, Adams J J, et al. Pen-on‐paper flexible electronics[J]. Advanced materials, 2011, 23(30): 3426–3430. Wang L, Chen D, Jiang K, et al. New insights and perspectives into biological materials for flexible electronics[J]. Chemical Society Reviews, 2017, 46(22): 6764–6815. Li T, Cao Y, Xue W, et al. Self-assembly of graphene-based planar micro-supercapacitor with selective laser etching-induced superhydrophobic/superhydrophilic pattern[J]. SN Applied Sciences, 2020, 2(2): 1–9. Zhang L, Jiang D, Dong T, et al. Overview of ionogels in flexible electronics[J]. The Chemical Record, 2020, 20(9): 948–967. MacDonald W A, Looney M K, MacKerron D, et al. Latest advances in substrates for flexible electronics[J]. Journal of the Society for Information Display, 2007, 15(12): 1075–1083. Yang Y, Gao W. Wearable and flexible electronics for continuous molecular monitoring[J]. Chemical Society Reviews, 2019, 48(6): 1465–1491. Hu J. Overview of flexible electronics from ITRI's viewpoint[C]//2010 28th VLSI Test Symposium (VTS). IEEE, 2010: 84–84. Yang Y, Gao W. Wearable and flexible electronics for continuous molecular monitoring[J]. Chemical Society Reviews, 2019, 48(6): 1465–1491. Sun Q J, Zhao X H, Zhou Y, et al. Fingertip-skin‐inspired highly sensitive and multifunctional sensor with hierarchically structured conductive graphite/polydimethylsiloxane foams[J]. Advanced Functional Materials, 2019, 29(18): 1808829. Fu Q, Chen Y, Sorieul M. Wood-based flexible electronics[J]. ACS nano, 2020, 14(3): 3528–3538. Zhang Y, Zhang L, Cui K, et al. Flexible electronics based on micro/nanostructured paper[J]. Advanced Materials, 2018, 30(51): 1801588. Ling H, Liu S, Zheng Z, et al. Organic flexible electronics[J]. Small Methods, 2018, 2(10): 1800070. Huang S, Liu Y, Zhao Y, et al. Flexible electronics: stretchable electrodes and their future[J]. Advanced Functional Materials, 2019, 29(6): 1805924. Guillen C, Herrero J. TCO/metal/TCO structures for energy and flexible electronics[J]. Thin Solid Films, 2011, 520(1): 1–17. Wang P, Hu M, Wang H, et al. The evolution of flexible electronics: from nature, beyond nature, and to nature[J]. Advanced Science, 2020, 7(20): 2001116. Wang Y, Sun L, Wang C, et al. Organic crystalline materials in flexible electronics[J]. Chemical Society Reviews, 2019, 48(6): 1492–1530. Liu Z, Xu J, Chen D, et al. Flexible electronics based on inorganic nanowires[J]. Chemical Society Reviews, 2015, 44(1): 161–192. Park S, Vosguerichian M, Bao Z. A review of fabrication and applications of carbon nanotube film-based flexible electronics[J]. Nanoscale, 2013, 5(5): 1727–1752. You R, Liu Y Q, Hao Y L, et al. Laser fabrication of graphene-based flexible electronics[J]. Advanced Materials, 2020, 32(15): 1901981. Caironi M, Noh Y Y. Large area and flexible electronics[M]. John Wiley & Sons, 2015. Zhang Q. Shooting flexible electronics[J]. Frontiers of Physics, 2021, 16(1): 1–3. Li D, Lai W Y, Zhang Y Z, et al. Printable transparent conductive films for flexible electronics[J]. Advanced materials, 2018, 30(10): 1704738. Zhao Y, Guo J. Development of flexible Li-ion batteries for flexible electronics[J]. InfoMat, 2020, 2(5): 866–878. Zhao Y, Guo J. Development of flexible Li-ion batteries for flexible electronics[J]. InfoMat, 2020, 2(5): 866–878. Bae G Y, Pak S W, Kim D, et al. Linearly and highly pressure-sensitive electronic skin based on a bioinspired hierarchical structural array[J]. Advanced Materials, 2016, 28(26): 5300–5306. Chen Z, Zhuo H, Hu Y, et al. Wood-derived lightweight and elastic carbon aerogel for pressure sensing and energy storage[J]. Advanced Functional Materials, 2020, 30(17): 1910292. Li Z, Zhang B, Li K, et al. A wide linearity range and high sensitivity flexible pressure sensor with hierarchical microstructures via laser marking[J]. Journal of Materials Chemistry C, 2020, 8(9): 3088–3096. Sun Y, Tai H, Yuan Z, et al. A Facile Strategy for Low Young's Modulus PDMS Microbeads Enhanced Flexible Capacitive Pressure Sensors[J]. Particle & Particle Systems Characterization, 2021, 38(7): 2100019. Zhong M, Zhang L, Liu X, et al. Wide linear range and highly sensitive flexible pressure sensor based on multistage sensing process for health monitoring and human-machine interfaces[J]. Chemical Engineering Journal, 2021, 412: 128649. Harrison M R, Clifton G D, Penneil A T, et al. Effect of heart rate on left ventricular diastolic transmitral flow velocity patterns assessed by Doppler echocardiography in normal subjects[J]. The American journal of cardiology, 1991, 67(7): 622–627. Additional Declarations No competing interests reported. Supplementary Files SupportingInformation.doc Cite Share Download PDF Status: Published Journal Publication published 01 Mar, 2023 Read the published version in Discover Nano → Version 1 posted Editorial decision: Major revision 19 Dec, 2022 Reviews received at journal 17 Dec, 2022 Reviews received at journal 06 Dec, 2022 Reviewers agreed at journal 30 Nov, 2022 Reviewers invited by journal 27 Nov, 2022 Editor assigned by journal 23 Nov, 2022 Submission checks completed at journal 23 Nov, 2022 First submitted to journal 21 Nov, 2022 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-2298137","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":154672474,"identity":"7d5e419e-b432-4af5-9b1f-d1096567e1aa","order_by":0,"name":"Xiaoming Chang","email":"data:image/png;base64,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","orcid":"","institution":"Physical Education College of Harbin Normal University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Xiaoming","middleName":"","lastName":"Chang","suffix":""}],"badges":[],"createdAt":"2022-11-21 17:14:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2298137/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2298137/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s11671-023-03788-7","type":"published","date":"2023-03-01T19:29:14+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":29673407,"identity":"388035b4-73e2-481a-a4b8-0e09b17ca52d","added_by":"auto","created_at":"2022-11-29 17:43:22","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2540589,"visible":true,"origin":"","legend":"\u003cp\u003e(a1-a3) Schematic of the P-HCF preparation process. (a4) The picture of the P-HCF device. (b) Schematic of flexible P-HCF pressure sensor. (c) The basic working principle of the P-HCF pressure sensor. (d) The picture of the P-HCF pressure sensor device.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/bcda183fdbcc8036614b34ac.jpeg"},{"id":29673404,"identity":"97363d57-63bb-493c-a8c9-931b5b82e954","added_by":"auto","created_at":"2022-11-29 17:43:21","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2183824,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The dimension diagrammatic sketch of P-HCF pressure sensor. (b) 3D surface profiles of HCFs (i: P\u003csub\u003e0.8\u003c/sub\u003e-HCF, ii: P\u003csub\u003e1\u003c/sub\u003e-HCF, iii: P\u003csub\u003e1.2\u003c/sub\u003e-HCF, iv: P\u003csub\u003e1.4\u003c/sub\u003e-HCF). (c) The working mechanism of P-HCF pressure sensor. Change of contact area (d), total deformation (e), and deformation of bulk films (f) of P-HCFs in response to different pressure.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/028c01561de34d9c22fadc2e.jpeg"},{"id":29673409,"identity":"852f13ef-70f5-46a8-8fff-b04e48bdd865","added_by":"auto","created_at":"2022-11-29 17:43:22","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2734457,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The I-V curves of the P-HCF pressure sensor. (b) Current responses to loading/unloading 24 Pa on the sensor. Inserts: the response time and recovery time. (c) Cyclic current responses of the P-HCF pressure sensor under different pressures. (d) Real-time pressure monitoring of the P1-HCF sensor. (e) Cyclic current responses of the sensor to 240 kPa under different frequencies.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/022c885ce8ed04ab9518dbf8.jpeg"},{"id":29673405,"identity":"c0eb6675-398f-44b0-8b1d-474e72c07ea3","added_by":"auto","created_at":"2022-11-29 17:43:21","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2387196,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Flexible P\u003csub\u003e1\u003c/sub\u003e-HCF pressure sensor attached on the wrist for pulse signals monitoring. (b) Flexible P1-HCF pressure sensor fixed on the biceps for muscle response monitoring. (c1-c3) Schematic of the pressure sensor array assembled from the P\u003csub\u003e1\u003c/sub\u003e-HCFs with 4 × 4 working units. (d1-d3) Finger and palm contact schematics with associated pressure maps on the pressure sensor array.\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/285be7f9e267760ccd51b412.jpeg"},{"id":29674713,"identity":"3d5d8620-7b47-486c-93d8-67d7e1f21a3f","added_by":"auto","created_at":"2022-11-29 17:51:22","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1120233,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic of the intelligent insole consisting of 16 working sensors. (b) The intelligent insole measures the distribution of plantar pressure throughout the running process. (c) Photographs of the smart glove and the control system's schematic design. (d, e) Current reactions to various motions and Morse code for \"BGI\" generated by bending fingers.\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/70e33ebc24e1c6f72167e36f.jpeg"},{"id":44721256,"identity":"8ac8df0d-09f9-47d7-8bb1-a3c6ffde473d","added_by":"auto","created_at":"2023-10-16 19:32:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":839680,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/56084a26-51cd-46c5-a0f0-bfac2c2bc1ba.pdf"},{"id":29673406,"identity":"bda9cb00-08f4-44a5-98b5-4af20f3d7e9c","added_by":"auto","created_at":"2022-11-29 17:43:21","extension":"doc","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1762304,"visible":true,"origin":"","legend":"","description":"","filename":"SupportingInformation.doc","url":"https://assets-eu.researchsquare.com/files/rs-2298137/v1/b9ed9d39a4cc77c001e4c137.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Wearable Electronic Based on Capacitive Flexible Pressure Sensor for Running Motion Monitoring","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe flexible pressure sensor is mainly based on the piezoresistive effect and pressure-capacitance effect to convert the pressure received by the device into the resistance or capacitance change of the device to realize the pressure sensing [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Therefore, flexible pressure sensing technology is one of the key technologies of intelligent wearable devices, and the development of this technology promotes the development of wearable devices [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The flexible wearable pressure sensing device is mainly used for health detection and motion detection of the human body, and realize the transformation from the human disease treatment mode to the disease prevention mode [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. For human health detection and motion detection, it mainly detects and analyzes micro pressure, such as pulse pressure, blood pressure, intraocular pressure, muscle movement and heart rate [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Because of rapid improvements in functional materials, flexible sensors, and integrated power systems, there has been a surge in interest in wearable electronic gadgets that can monitor and diagnose individual health conditions in real time [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Flexible pressure-sensitive devices have continued to garner interest in the disciplines of prosthetics, health monitoring, and robotics. Depending on the sensing material and mechanism, flexible pressure sensors are categorized as resistive, capacitive, piezoelectric, or optical [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Among these pressure sensors, resistive pressure sensors are preferred owing to their simple readout mechanism and cost benefits [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Resistive pressure sensors can convert the pressure received into the change of its own resistance, thus realizing the pressure sensing. Generally, engraving process is required to prepare materials with micro nano surface structure. Laser engraving uses advanced laser technology for processing, which belongs to non-contact processing, which avoids scratching the workpiece and achieves engraving, cutting and polishing at the same time. However, traditional mechanical engraving must be in contact with the workpiece, and the workpiece needs to be fixed, which will scratch the workpiece and cause waste of materials. Laser engraving has low energy consumption, no noise and no pollution, which is an energy-saving and environmental protection processing method. However, traditional engraving methods cause noise pollution and require large energy consumption [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Extensive research was undertaken in this study to broaden the detection band and improve the sensitivity for practical application. Numerous successful ways involving novel materials and better architectures were used to increase pressure sensitivity [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Sun et al. have presented a conductive graphite/polydimethylsiloxane (G/PDMS) foam sheet with a stratified surface microstructure that exhibits a 245 kPa\u003csup\u003e-1\u003c/sup\u003e sensitivity [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Numerous materials have been researched for use in pressure sensors, including conducting polymers, graphite, and nanomaterials such as carbon nanotubes (CNTs), graphite, and carbon nanofibers (CF) [\u003cspan additionalcitationids=\"CR16 CR17 CR18 CR19 CR20 CR21\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Additionally, degradation efficiency may be enhanced by developing microtomes and microcones on the surface of the material and by generating microscopic and nanoscale micropores inside the material [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. However, when subjected to high pressures, the material's compressibility declines, resulting in saturation of the number of conducting routes and contact areas in pressure-resistant and contact-type components, resulting in lower sensitivity and irregular response.\u003c/p\u003e \u003cp\u003eConsequently, flexible sensors have historically struggled to achieve acceptable sensitivity in the high voltage range [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. A sensor's linear sensitivity is defined as the relationship between its output signal and applied load. Pressure sensors in practical applications must work in the linear sensitivity range, which maximizes cost-effectiveness and eliminates the need for further signal processing to receive the correct information [\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Flexible pressure sensors, on the other hand, can be easily integrated with existing signal conditioning systems on the market, which means they have more market potential in industries like artificial intelligence, healthcare, and more. Nonetheless, there are few papers that describe sensors with linear sensitivity around the entire spectral resolution [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Researchers are continuing to work on extending the band and responsiveness of linear sensing. Cho et al., for example, developed a surface using reduced graphene oxide (rGO) and an array of PDMS microdome structures [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The skin has a sensitivity of 8.5 kPa\u003csup\u003e-1\u003c/sup\u003e. Wong et al. transformed a stiff non-conductive bulk material into a flexible conductive carbon/silicon composite for use as a sensing material, achieving 10.7 kPa\u003csup\u003e-1\u003c/sup\u003e across a broad pressure range (up to 100 kPa) [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Yang et al. recently revealed a pressure sensor with a layered microstructure with an even better sense of 15.4 kPa\u003csup\u003e-1\u003c/sup\u003e across a broad linear range of over 200 kPa [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Even though comparative research has yielded more favorable findings, they continue to fall short of meeting the criteria of actual applications in the high-pressure range. To expand the application's scope, it is critical to retain a high level of sensitivity whilst expanding the linear detection range.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eHere, we propose a hybrid conductive elastomeric film oxide-based material with a concave-shape micro-patterned array (P-HCF) on the surface that sustainably shows the necessary sensing qualities with an excellent linear sensitivity of 31.92 kPa\u003csup\u003e-1\u003c/sup\u003e throughout a wide pressure range of 24 Pa to 720 kPa, as well as the ability to sense pressure changes in real time. In this design, PDMS acts as a flexible dielectric in the P-HCF flexible pressure sensor device. When the device is subjected to pressure, the PDMS layer will deform and then cause the pressure device to generate different sensing signal. MXene (MX) can be used as adsorbent due to its unique layered structure, high specific surface area, excellent surface hydrophilicity and rich active sites. The one-dimensional carbon fibers (CF) is introduced into PDMS as a conductive material to enhance its conductivity. As PDMS is hydrophobic, MX needs to be added as adsorbent to fuse CF and PDMS. Compared with the previous sensor materials, we introduced MS into the dielectric elastomer of the sensor, which greatly enhanced the distribution uniformity of conductive materials inside the dielectric elastomer because MS has good adhesion. Unlike conventional flexible detectors, which rely on changes in surface structure to achieve linear sensitivity, this sensing material starts from the surface micro-nano texture characteristics by forming a micro-nano hybrid framework from a multidimensional carbon material in P-HCF by forming a concave-shape micro-pattern that mimics the structure of a human fingerprint. From a macro viewpoint, the array provides multi-step sensing as well. According to the results, the pressure sensor works very well and has the potential for running motion monitoring.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"2. Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Preparation of P-HCF film\u003c/h2\u003e \u003cp\u003eThe P-HCF was fabricated by molding the liquid mixture of conductive elastomers on templates. CFs (8 m diameter, 10 to 100 m length) (400 mesh, Haotian Nano Technology Company) and PDMS (Dow Corning Sylgard 184; the weight ratio of base to curing agent was 10:1) were mixed by a planetary centrifugal mixer. Following that, MS (CCI, Jujo Chemical Co., Ltd. Shenzhen, China) was added to the CFs/PDMS and mixed for 3 hours at 400 rpm using an overhead stirrer (IKA, RW20). As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(a1-a3), the conductive elastomer was bladed onto patterned quartz templates, which were engraved by laser flash (Speedy 360, 60 W) based on programmable patterning with different spacings and depths. The spacings of micro-patterns were 200 \u0026micro;m, 300 \u0026micro;m, and 400 \u0026micro;m; and the depths were 25 \u0026micro;m, 55 \u0026micro;m, 80 \u0026micro;m and 110 \u0026micro;m. The HCF film containing micropatterns were evaporated to dryness in a vacuum oven, cured completely at 100\u0026deg;C, and then peeled away from the template.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Characterization of P-HCF pressure sensor.\u003c/h2\u003e \u003cp\u003eThe square P-HCF is adhered to the bottom copper laminate electrode using conductive silver glue with the patterned surface facing up. Then, the elastomer top is covered with copper foil to form the pressure sensor. The electrical responses of the sensors were measured by using the mechanical performance testing system (MTS E43.104) and a digital source meter (Keysight B2902A). The applied voltage for measurements of all electrical properties was 0.05 V DC. The curves of pulse monitoring and pressure array were acquired by source meter and electrochemical workstation (Metrohm, M204), respectively.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results And Discussion","content":"\u003cp\u003eConductive elastomeric films comprising micro-and nano-hybrid carbon materials with curved concave-shape micro patterned arrays (P-HCFs) can be generated simply and reliably, as seen in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(a). Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(a4) shows the picture of P-HCF device. Besides, Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(b) illustrates the layout of the flexible pressure sensing element: Between two copper electrodes composed of copper-clad plates, P-HCF is sandwiched. The pressure sensor\u0026apos;s fundamental operation is shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(c). The external pressure changed the contact area between the concave-shape micro-patterned array on the surface and the upper electrode, leading to the decrease in contact resistance. The conductive electrode is copper foil, which is mainly used as two plates of capacitance to conduct the capacitance change of the pressure sensor, meanwhile, the contact resistance formed between copper electrode and P-HCF film is also an important factor of feedback pressure. Correspondingly, the total current of P-HCF sensor rose with the increase in applied pressure. Moreover, the photograph of the P-HCF pressure sensor is illustrated in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(d).\u003c/p\u003e\n\u003cp\u003eTo show the influence of curved microstructure height on the sensitivity and linear band of flexible pressure sensors, four distinct P-HCFs (P0.8-HCF, P1-HCF, P1.2-HCF, and P1.4-HCF) with varying pattern heights were produced while maintaining a pattern spacing and size of 2 mm, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(a). When applying pressure to the pliable pressure sensor shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(b), the sensor\u0026apos;s performance is demonstrated. The pressure sensor\u0026apos;s sensitivity (S) is described as S= (\u0026Delta;I/I)/\u0026Delta;P where \u0026Delta;I and \u0026Delta;P note the measured current and pressure changes, respectively, and I denotes the starting current without load. According to the data, as the height of the projectionettes increases, the standardized change in current increases as well (\u0026Delta;I/I) eventually approaches a linear relationship with the applied pressure across the whole range of 24 Pa to 720 kPa, as shown in Fig.S1 of Supporting Information. Furthermore, the working mechanism of P-HCF pressure sensor is composed of two components: contact resistance (Rc) and film resistance (Rf), as illustrated in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(c). In detail, different pressures will lead to different degrees of deformation of P-HCF pressure sensor. Meanwhile, the distance between CFs and carbon nanoparticles (CNPs) inside P-HCF reduced, resulting on a sharp increase in conductive paths consisting of the physical contact and tunneling effect. As shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(d), when the applied pressure grows, the sensor\u0026apos;s contact surface will also increase. An electron tunnel junction is formed by sandwiching a thin insulating layer between two metal conductors. It is found that electrons can pass through the tunnel junction, that is, electrons can pass through the insulating layer, which is the tunnel effect. Contact effect is an electrical effect caused by two different materials when they are in contact, which is different from that when they are not in contact and exist independently.\u003c/p\u003e\n\u003cp\u003eAs the pressure load increases, the change in Rf due to tunneling and contact effects between the internal conducting filler and the body block caused by pattern deformation progressively rises, increasing the sensor\u0026apos;s sensitivity in conjunction with Rc. Until the pattern becomes flat, the change in resistance is primarily determined by the Rf caused by the compressive deformation. As the micropattern\u0026apos;s height grows, the process of micropattern to flatten the bulk film takes more time and changes shape more, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(f). As a consequence, the P1-HCF sensor\u0026apos;s sensitivity diminishes and tends to saturate at high pressure, while sensors with micro-patterns of various heights exhibit essentially linear sensitivity over the entire detecting range, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(b). Additionally, the P1-HCF sensor has a high linear test range of 24 Pa to 720 kPa. This suggests that with a sufficiently complex micro-pattern design, the conductive material compensates for the contacts\u0026apos; saturation effect as the pressure rises, allowing for a broad linear detection range. The compressibility of the pressure sensor rises with increasing spacing because the efficient Young\u0026apos;s modulus of the micropattern decreases at the same pressure [\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e]. Enhanced micropattern distortion results in a greater contact area and hence extreme susceptibility. However, micropatterns with a relatively large spacing flatten first, and the sensor\u0026apos;s sensitivity drops as pressure increases, resulting in a loss of linearity over the whole sensitivity range. On the other hand, it was discovered that sensors with densely separated micropatterns display linear sensitivity across a large sensing area owing to the synergistic impact of contact resistance and film resistance formed during sensing. In the end, the best material to use for a pressure sensor was P1-HCF with a pitch and size of 2 mm [\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e]. Compared to previous work [\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e], the pressure sensor we designed can provide larger pressure test range, but the sensing sensitivity is still limited.\u003c/p\u003e\n\u003cp\u003eThe P1-HCF sensor\u0026apos;s current-voltage (I-V) curve was tested at various pressure levels ranging from \u0026minus;\u0026thinsp;3.6 Vto 3.6 V. We observed a clear linear connection and a consistent response, showing that the ohmic properties are stable (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea). The resistance (slope of the curve) reduces proportionately as the applied load rises. To determine the sensor\u0026apos;s detection limit (LOD), the present response to stress was established by the following: inserting and lowering a 0.24 g, demonstrating that the sensor is capable of tracking minute pressure fluctuations up to 24 Pa, as seen in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(b). The inset shows the sensor\u0026apos;s immediate sensing reaction time (40 ms) and recovery time (20 ms), indicating that the sensor is fast and equivalent to human skin pressure when exposed to external pressure. As present in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(c), the sensor is capable of achieving rapid and linear current changes across a modest pressure range. It is worth noticing that the response signal exhibits a strong linear association with the pressure level as the pressure increases in the high-pressure range (120\u0026thinsp;~\u0026thinsp;720 kPa), as shown in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(d). The P1-HCF sensor\u0026apos;s response at varied compression frequencies with a constant pressure load of 240 kPa is shown in Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e(e). The pressure sensor is shown to react frequently at various compression frequencies. Furthermore, the reliability test and reversibility test of pressure sensor device performance are shown in Fig. S2 and Fig. S3 of Supporting Information. From the results, the pressure sensor device has good stability.\u003c/p\u003e\n\u003cp\u003eTo assess the possibility of pressure sensors being used in the diagnosis of cardiovascular illnesses, sensors were worn on the wrist, and the arterial pulse was measured in real-time, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(a). A pulse rate of 70 beats per minute was measured here, which is the rate of a healthy adult [\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e]. The usual arterial waveforms such as shock wave (P\u003csub\u003e1\u003c/sub\u003e), tidal wave (P\u003csub\u003e2\u003c/sub\u003e), and diastolic wave (P\u003csub\u003e3\u003c/sub\u003e) may be recognized without signal amplification or post-processing. Parkinson\u0026apos;s disease (PD) is a neurodegenerative illness that is most often diagnosed in middle-aged and older adults, and muscular stiffness is a common symptom of PD patients. Passive motor resistance in flexors and extensors is a common complaint throughout the range of action. Parkinson\u0026apos;s patients mainly show static tremor, slowing down and muscle rigidity. Their gait has certain characteristics, mainly showing flustered gait. With the progress of the disease, their gait abnormalities become more obvious. Muscle stiffness is determined in clinical practice by passive limb movement at the joint. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(b) depicts a patient\u0026apos;s simulated muscular resistance during passive motion with the sensor connected to the biceps muscle, and depicts the accompanying current changes, suggesting that the P\u003csub\u003e1\u003c/sub\u003e-HCF sensor has potential application value in detecting Parkinson\u0026apos;s disease. Additionally, the spatial distribution and pressure values may be seen by including a flexible pressure sensor in the sensing array. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(c1-c2) illustrates a 4*4-telescopic pressure sensor array comprised of a P1-HCF sensor and a flexible telescopic circuit that fits inside a hemispherical mold, illustrating that telescopic sensing arrays may be adapted to complicated surfaces in real applications. 3D mapped pictures show pressure values and locations on fingers and palms by height and position, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e(d1-d3). Sensors now pick up on the distribution of pressure and rough outline of objects.\u003c/p\u003e\n\u003cp\u003eTo monitor plantar pressure effectively, linear sensing capacity across a wide range of up to several hundred kilopascals is required, as is high sensitivity. As a result, we designed a flexible smart insole with 16 working units located at the toes, forefoot, lateral, and rearfoot, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(a). The foot pressure distribution of a person weighing 60 kg in a standing posture is shown in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(b). The flexible sensors\u0026apos; broad linearity and excellent sensitivity enable them to gather pressure correctly at each spot. Additionally, the pressure distribution changes during running motion were rebuilt using sixteen consecutive sensors. Interactions between humans and devices, known as human-machine interfaces, are critical components of AI. They have already been implemented in a variety of ways, including embedded platforms in wearable devices such as smartwatch and garments as well as in wristbands, keypads, and microphones. As illustrated in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(c), a flexible pressure sensor-based human-machine interface was produced by connecting a sensing device to the fingers of a textile glove. Two layers of flexible circuits (top and bottom) and P1-HCF were used to construct the sensing device. The output curves may depict various hand movements by combining the on/off and amplitude of the five signals provided by the fingers, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(d). Additionally, the length and regularity of the signals may be set using Morse code, which are determined by the duration and intensity of thumb bending, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e(e).\u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eIn conclusion, a flexible P-HCF pressure sensor was reported. The multi-step sensing technique enables an extensive dynamic range and great linear sensitivity. The sensing material P-HCF enables the fabrication of the hybrid structured conductive films with concave-shape micro-patterned arrays. 1D CF and 2D MX are used as conductive fillers in PDMS, resulting in a multi-step sensing structure at the microscale network. Filler substrate elastomeric materials have a greatly improved detection range and responsiveness as a result of this improvement. Besides, the sensitivity of P-HCF pressure sensor can reach 31.92 kPa\u003csup\u003e-1\u003c/sup\u003e, and meanwhile, the linear band of P-HCF pressure sensor can arrive at 24 Pa \u0026minus;\u0026thinsp;720 kPa, which makes it a good choice for pressure testing applications. This sensor may be used to detect human pulses and aid in the diagnosis of Parkinson's disease. Simultaneously, it may be useful for monitoring human gait and determining the distribution of foot pressure. This research combines multifunctional material technology with flexible sensing technology, which provides a new idea for the running motion monitoring.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026rsquo; contributions\u003c/p\u003e\n\u003cp\u003eConceptualization, Xiaoming Chang; formal analysis, Xiaoming Chang; writing-original draft preparation, Xiaoming Chang; writing-review and editing, Xiaoming Chang; visualization, Xiaoming Chang; supervision, Xiaoming Chang. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eAll data and materials are available without restrictions.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eShi J, Wang L, Dai Z, et al. Multiscale hierarchical design of a flexible piezoresistive pressure sensor with high sensitivity and wide linearity range[J]. Small, 2018, 14(27): 1800819.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi R, Zhou Q, Bi Y, et al. Research progress of flexible capacitive pressure sensor for sensitivity enhancement approaches[J]. Sensors and Actuators A: Physical, 2021, 321: 112425.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y, Gong M, Wan P. MXene hydrogel for wearable electronics[J]. Matter, 2021, 4(8): 2655\u0026ndash;2658.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi N, Peng J, Ong W J, et al. MXenes: an emerging platform for wearable electronics and looking beyond[J]. Matter, 2021, 4(2): 377\u0026ndash;407.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWan D, Yang J, Cui X, et al. Human body-based self-powered wearable electronics for promoting wound healing driven by biomechanical motions[J]. Nano Energy, 2021, 89: 106465.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGates B D. Flexible electronics[J]. Science, 2009, 323(5921): 1566\u0026ndash;1567.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGao W, Ota H, Kiriya D, et al. Flexible electronics toward wearable sensing[J]. Accounts of chemical research, 2019, 52(3): 523\u0026ndash;533.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun Y, Rogers J A. Inorganic semiconductors for flexible electronics[J]. Advanced materials, 2007, 19(15): 1897\u0026ndash;1916.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRusso A, Ahn B Y, Adams J J, et al. Pen-on‐paper flexible electronics[J]. Advanced materials, 2011, 23(30): 3426\u0026ndash;3430.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang L, Chen D, Jiang K, et al. New insights and perspectives into biological materials for flexible electronics[J]. Chemical Society Reviews, 2017, 46(22): 6764\u0026ndash;6815.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi T, Cao Y, Xue W, et al. Self-assembly of graphene-based planar micro-supercapacitor with selective laser etching-induced superhydrophobic/superhydrophilic pattern[J]. SN Applied Sciences, 2020, 2(2): 1\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang L, Jiang D, Dong T, et al. Overview of ionogels in flexible electronics[J]. The Chemical Record, 2020, 20(9): 948\u0026ndash;967.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMacDonald W A, Looney M K, MacKerron D, et al. Latest advances in substrates for flexible electronics[J]. Journal of the Society for Information Display, 2007, 15(12): 1075\u0026ndash;1083.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang Y, Gao W. Wearable and flexible electronics for continuous molecular monitoring[J]. Chemical Society Reviews, 2019, 48(6): 1465\u0026ndash;1491.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu J. Overview of flexible electronics from ITRI's viewpoint[C]//2010 28th VLSI Test Symposium (VTS). IEEE, 2010: 84\u0026ndash;84.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang Y, Gao W. Wearable and flexible electronics for continuous molecular monitoring[J]. Chemical Society Reviews, 2019, 48(6): 1465\u0026ndash;1491.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun Q J, Zhao X H, Zhou Y, et al. Fingertip-skin‐inspired highly sensitive and multifunctional sensor with hierarchically structured conductive graphite/polydimethylsiloxane foams[J]. Advanced Functional Materials, 2019, 29(18): 1808829.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFu Q, Chen Y, Sorieul M. Wood-based flexible electronics[J]. ACS nano, 2020, 14(3): 3528\u0026ndash;3538.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y, Zhang L, Cui K, et al. Flexible electronics based on micro/nanostructured paper[J]. Advanced Materials, 2018, 30(51): 1801588.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLing H, Liu S, Zheng Z, et al. Organic flexible electronics[J]. Small Methods, 2018, 2(10): 1800070.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang S, Liu Y, Zhao Y, et al. Flexible electronics: stretchable electrodes and their future[J]. Advanced Functional Materials, 2019, 29(6): 1805924.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuillen C, Herrero J. TCO/metal/TCO structures for energy and flexible electronics[J]. Thin Solid Films, 2011, 520(1): 1\u0026ndash;17.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang P, Hu M, Wang H, et al. The evolution of flexible electronics: from nature, beyond nature, and to nature[J]. Advanced Science, 2020, 7(20): 2001116.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Y, Sun L, Wang C, et al. Organic crystalline materials in flexible electronics[J]. Chemical Society Reviews, 2019, 48(6): 1492\u0026ndash;1530.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu Z, Xu J, Chen D, et al. Flexible electronics based on inorganic nanowires[J]. Chemical Society Reviews, 2015, 44(1): 161\u0026ndash;192.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark S, Vosguerichian M, Bao Z. A review of fabrication and applications of carbon nanotube film-based flexible electronics[J]. Nanoscale, 2013, 5(5): 1727\u0026ndash;1752.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYou R, Liu Y Q, Hao Y L, et al. Laser fabrication of graphene-based flexible electronics[J]. Advanced Materials, 2020, 32(15): 1901981.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCaironi M, Noh Y Y. Large area and flexible electronics[M]. John Wiley \u0026amp; Sons, 2015.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Q. Shooting flexible electronics[J]. Frontiers of Physics, 2021, 16(1): 1\u0026ndash;3.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi D, Lai W Y, Zhang Y Z, et al. Printable transparent conductive films for flexible electronics[J]. Advanced materials, 2018, 30(10): 1704738.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao Y, Guo J. Development of flexible Li-ion batteries for flexible electronics[J]. InfoMat, 2020, 2(5): 866\u0026ndash;878.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao Y, Guo J. Development of flexible Li-ion batteries for flexible electronics[J]. InfoMat, 2020, 2(5): 866\u0026ndash;878.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBae G Y, Pak S W, Kim D, et al. Linearly and highly pressure-sensitive electronic skin based on a bioinspired hierarchical structural array[J]. Advanced Materials, 2016, 28(26): 5300\u0026ndash;5306.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen Z, Zhuo H, Hu Y, et al. Wood-derived lightweight and elastic carbon aerogel for pressure sensing and energy storage[J]. Advanced Functional Materials, 2020, 30(17): 1910292.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi Z, Zhang B, Li K, et al. A wide linearity range and high sensitivity flexible pressure sensor with hierarchical microstructures via laser marking[J]. Journal of Materials Chemistry C, 2020, 8(9): 3088\u0026ndash;3096.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun Y, Tai H, Yuan Z, et al. A Facile Strategy for Low Young's Modulus PDMS Microbeads Enhanced Flexible Capacitive Pressure Sensors[J]. Particle \u0026amp; Particle Systems Characterization, 2021, 38(7): 2100019.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhong M, Zhang L, Liu X, et al. Wide linear range and highly sensitive flexible pressure sensor based on multistage sensing process for health monitoring and human-machine interfaces[J]. Chemical Engineering Journal, 2021, 412: 128649.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarrison M R, Clifton G D, Penneil A T, et al. Effect of heart rate on left ventricular diastolic transmitral flow velocity patterns assessed by Doppler echocardiography in normal subjects[J]. The American journal of cardiology, 1991, 67(7): 622\u0026ndash;627.\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":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-nano","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"narl","sideBox":"Learn more about [Discover Nano](https://www.springer.com/journal/11671)","snPcode":"11671","submissionUrl":"https://submission.nature.com/new-submission/11671/3","title":"Discover Nano","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Flexible pressure sensor, low-cost, high linear sensitivity, wide detection range","lastPublishedDoi":"10.21203/rs.3.rs-2298137/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2298137/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe flexible pressure sensor is expected to be applied in the new generation of sports wearable electronic devices. Developing flexible pressure sensors with a wide linear range and great sensitivity, however, remains a significant barrier. In this work, we propose a hybrid conductive elastomeric film oxide-based material with a concave-shape micro-patterned array (P-HCF) on the surface that sustainably shows the necessary sensing qualities. To enhance sensing range and sensitivity, one-dimensional carbon fibers (CF) and two-dimensional MXene (MX) are incorporated into the polydimethylsiloxane (PDMS) matrix to form a three-dimensional conductive network. Micro-patterns with a curved shape in P-HCFs are designed to resemble a human fingerprint and were able to linear sensitivity across the sensing range by controlling the pressure distribution inside the material. Besides, the sensitivity of P-HCF pressure sensor can reach 31.92 kPa\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and meanwhile, the linear band of P-HCF pressure sensor can arrive at 24 Pa \u0026minus;\u0026thinsp;720 kPa, which makes it a good choice for sports monitoring. The designed pressure sensor can be used to monitor the foot pressure during running. By analyzing the gait information during running, it can provide data support and strategy improvement for running. This new dual working mode pressure P-HCF sensor will provide a new way for the development of intelligent sports.\u003c/p\u003e","manuscriptTitle":"A Wearable Electronic Based on Capacitive Flexible Pressure Sensor for Running Motion Monitoring","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-11-29 17:43:17","doi":"10.21203/rs.3.rs-2298137/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-12-19T08:12:54+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-12-17T15:47:54+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-12-07T03:43:56+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"7221faa8-6b25-464d-8bbb-c6229492ec8f","date":"2022-12-01T02:08:47+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-11-28T02:05:50+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-11-24T04:03:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-11-24T04:03:53+00:00","index":"","fulltext":""},{"type":"submitted","content":"Nanoscale Research Letters","date":"2022-11-21T17:09:08+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-nano","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"narl","sideBox":"Learn more about [Discover Nano](https://www.springer.com/journal/11671)","snPcode":"11671","submissionUrl":"https://submission.nature.com/new-submission/11671/3","title":"Discover Nano","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"48b14833-3730-4c7d-b1a1-d050d3ce8336","owner":[],"postedDate":"November 29th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T19:30:53+00:00","versionOfRecord":{"articleIdentity":"rs-2298137","link":"https://doi.org/10.1186/s11671-023-03788-7","journal":{"identity":"discover-nano","isVorOnly":false,"title":"Discover Nano"},"publishedOn":"2023-03-01 19:29:14","publishedOnDateReadable":"March 1st, 2023"},"versionCreatedAt":"2022-11-29 17:43:17","video":"","vorDoi":"10.1186/s11671-023-03788-7","vorDoiUrl":"https://doi.org/10.1186/s11671-023-03788-7","workflowStages":[]},"version":"v1","identity":"rs-2298137","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2298137","identity":"rs-2298137","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}