Preparation and performance of capacitive sensors with biomimetic skin wrinkle structure
-
摘要: 随着智能可穿戴技术的快速发展,柔性电容式传感器因其制备工艺简单及优良的电学性能,在健康监测、人机交互、电子皮肤等领域展现出广阔的应用前景。本文围绕提升电容式传感器的检测范围和耐久性为目标,提出了一种基于聚二甲基硅氧烷(PDMS)和可膨胀微球复合介电层的仿生皮肤褶皱结构的电容式传感器。用SEM分析了介电层的结构形貌,并研究了该传感器的电学性能和人体适用性。结果表明:电容式传感器具有较宽的检测范围(0-242 kPa)、高灵敏度(
0.0079 kPa−1)、快速响应时间(230 ms)以及优异的稳定耐久性(9500 次循环);同时,还具有较好的非接触感测性能,其非接触灵敏度为0.59%/cm。在实际应用中,该传感器可用于监测手指、手腕、膝盖等关节的弯曲运动,以及眨眼、张口等细微的生理信号。该电容式传感器在运动监测和健康监测领域具有潜在的应用价值。Abstract: With the rapid development of intelligent wearable technology, flexible capacitive sensors have shown broad application prospects in fields such as health monitoring, human-computer interaction, and electronic skin due to their simple preparation process and excellent electrical property. In order to improve the detection range and durability of the capacitive sensors, a capacitive sensor based on polydimethylsiloxane (PDMS) composite dielectric layer and expandable microsphere imitating the skin wrinkle structure is proposed. The structural morphology of the dielectric layer was evaluated by SEM and the electrical properties and human suitability of the sensor were investigated. The results show that the capacitive sensor has a wide detection range (0-242 kPa), high sensitivity (0.0079 kPa−1), fast response time (230 ms), and excellent stable durability (9500 cycles). It also has good non-contact sensing performance with a non-contact sensitivity of 0.59%/cm. In practical applications, this sensor can accurately monitor bending movements of joints such as fingers, wrists and knees, as well as subtle physiological signals such as blinking and opening the mouth. The capacitive sensor has potential applications in the field of motion monitoring and health monitoring. -
图 2 聚二甲基硅氧烷(PDMS)-可膨胀微球介电层和纯PDMS介电层的微观形貌:(a) 可膨胀微球膨胀前的SEM照片;(b)可膨胀微球膨胀后的SEM照片;(c) PDMS-可膨胀微球介电层光学显微镜照片;(d) PDMS-可膨胀微球介电层的SEM照片;(e) PDMS-可膨胀微球介电层实物照片;(f) PDMS-可膨胀微球介电层横截面的SEM照片;(g) 纯PDMS介电层的SEM;(h) 纯PDMS介电层横截面的SEM照片。
Figure 2. Microscopic morphology of polydimethylsiloxane (PDMS)-expandable microsphere dielectric layer and pure PDMS dielectric layer: (a) SEM image of expandable microspheres before expansion; (b) SEM image of expandable microspheres after expansion; (c) PDMS-expandable microsphere dielectric layer optical microscope picture; (d) SEM image of PDMS-expandable microsphere dielectric layer; (e) Photographic of PDMS-expandable microsphere dielectric layer; (f) SEM image of PDMS-expandable microsphere dielectric layer cross-section; (g) SEM of pure PDMS dielectric layer; (h) SEM image of pure PDMS dielectric layer cross-section.
图 4 电容式传感器压力传感性能:(a) 压力灵敏度;(b) 不同压力下的电容响应;(c) 在2 kPa压力下对传感器进行循环施压的电容响应数据;(d-e) 响应/回复时间;(f) 压力耐久性;(g) 电容式传感器性能对比图
Figure 4. Capacitive sensor pressure sensing performance: (a) Pressure sensitivity; (b) Capacitive response at different pressures; (c) Capacitive response data for cyclic pressure application to the sensor at 2 kPa pressure; (d-e) Response/recovery time; (f) Pressure durability; (g) Performance comparison of capacitive sensors
图 5 电容式传感器非接触性能:(a) 非接触传感示意图;(b) 非接触灵敏度;(c) 不同距离下的电容响应;(d) 不同手指根数的电容响应(5 cm高度);(e) 非接触耐久性
Figure 5. Capacitive sensor non-contact performance: (a) Non contact sensing schematic diagram; (b) Non-contact sensitivity; (c) Capacitive response at different distances; (d) Capacitive response for different number of fingers (5 cm height); (e) Non-contact durability
图 8 电容式传感器在外加压力下的响应演示:(a1-b2) 传感器对快速触摸和重量压力的电容响应;(c1-d2) 检测各种重复动作,包括点击鼠标和抓烧杯;(e-g) 检测指尖、不锈钢圆柱体和尺子尖对传感器的重复敲击
Figure 8. Demonstration of the capacitive sensor in response to exerted pressures: (a-b) Capacitive response of the sensor to fast touch and weight pressure; (c-d) Detection of various repeated actions, including clicking the mouse and grasping the beaker; (e-g) Detection of the repeated strikes of the sensor by fingertips, stainless steel cylinders and ruler tips
图 9 电容式传感器用于摩斯密码应用:(a) 阿拉伯数字和英文字母摩斯密码表;(b-c) 不同阿拉伯数字的摩斯密码电容信号;(d-e) 不同英文字母的摩斯密码电容信号;(f) 不同单词的摩斯密码电容信号
Figure 9. Capacitive sensors for morse code applications: (a) Morse code table of Arabic numerals and English letters; (b-c) Morse code capacitive signals with different arabic numerals; (d-e) Morse code capacitive signals for different alphabets; (f) Morse code capacitive signals for different words
-
[1] HE Z, WANG K, ZHAO Z, et al. A wearable flexible acceleration sensor for monitoring human motion[J]. Biosensors, 2022, 12(8): 620. doi: 10.3390/bios12080620 [2] MAITY D, RAJAVEL K, RAJENDRA KUMAR R T. MWCNT enabled smart textiles based flexible and wearable sensor for human motion and humidity monitoring[J]. Cellulose, 2021, 28: 2505-2520. doi: 10.1007/s10570-020-03617-5 [3] CHEN S, QI J, FAN S, et al. Flexible wearable sensors for cardiovascular health monitoring[J]. Advanced Healthcare Materials, 2021, 10(17): 2100116. doi: 10.1002/adhm.202100116 [4] CUI X, HUANG F, ZHANG X, et al. Flexible pressure sensors via engineering microstructures for wearable human-machine interaction and health monitoring applications[J]. Iscience, 2022, 25(4). [5] NI Y, ZANG X, CHEN J, et al. Flexible MXene-based hydrogel enables wearable human–computer interaction for intelligent underwater communication and sensing rescue[J]. Advanced Functional Materials, 2023, 33(49): 2301127. doi: 10.1002/adfm.202301127 [6] ZHANG H, ZHANG D, GUAN J, et al. A flexible wearable strain sensor for human-motion detection and a human–machine interface[J]. Journal of Materials Chemistry C, 2022, 10(41): 15554-15564. doi: 10.1039/D2TC03147G [7] JEONG H, NOH Y, KO S H, et al. Flexible resistive pressure sensor with silver nanowire networks embedded in polymer using natural formation of air gap[J]. Composites Science and Technology, 2019, 174: 50-57. doi: 10.1016/j.compscitech.2019.01.028 [8] DU D, MA X, AN W, et al. Flexible piezoresistive pressure sensor based on wrinkled layers with fast response for wearable applications[J]. Measurement, 2022, 201: 111645. doi: 10.1016/j.measurement.2022.111645 [9] HWANG J, KIM Y, YANG H, et al. Fabrication of hierarchically porous structured PDMS composites and their application as a flexible capacitive pressure sensor[J]. Composites Part B: Engineering, 2021, 211: 108607. doi: 10.1016/j.compositesb.2021.108607 [10] NIU H, WEI X, LI H, et al. Micropyramid array bimodal electronic skin for intelligent material and surface shape perception based on capacitive sensing[J]. Advanced Science, 2024, 11(3): 2305528. doi: 10.1002/advs.202305528 [11] YANG Y, PAN H, XIE G, et al. Flexible piezoelectric pressure sensor based on polydopamine-modified BaTiO3/PVDF composite film for human motion monitoring[J]. Sensors and Actuators A: Physical, 2020, 301: 111789. doi: 10.1016/j.sna.2019.111789 [12] HOU X, ZHANG S, YU J, et al. Flexible piezoelectric nanofibers/polydimethylsiloxane-based pressure sensor for self-powered human motion monitoring[J]. Energy Technology, 2020, 8(3): 1901242. doi: 10.1002/ente.201901242 [13] SYAMINI J, CHANDRAN A. Mylar interlayer-mediated performance enhancement of a flexible triboelectric nanogenerator for self-powered pressure sensing application[J]. ACS Applied Electronic Materials, 2023, 5(2): 1002-1012. doi: 10.1021/acsaelm.2c01525 [14] ZHONG Y, WANG J, HAN L, et al. High-performance flexible self-powered triboelectric pressure sensor based on chemically modified micropatterned PDMS film[J]. Sensors and Actuators A: Physical, 2023, 349: 114013. doi: 10.1016/j.sna.2022.114013 [15] QIN J, YIN L J, HAO Y N, et al. Flexible and stretchable capacitive sensors with different microstructures[J]. Advanced Materials, 2021, 33(34): 2008267. doi: 10.1002/adma.202008267 [16] DONG T, GU Y, LIU T, et al. Resistive and capacitive strain sensors based on customized compliant electrode: Comparison and their wearable applications[J]. Sensors and Actuators A: Physical, 2021, 326: 112720. doi: 10.1016/j.sna.2021.112720 [17] SUN X, LIU T, ZHOU J, et al. Recent applications of different microstructure designs in high performance tactile sensors: A review[J]. IEEE Sensors Journal, 2021, 21(9): 10291-10303. doi: 10.1109/JSEN.2021.3061677 [18] HE X, LIU Z, SHEN G, et al. Microstructured capacitive sensor with broad detection range and long-term stability for human activity detection[J]. npj Flexible Electronics, 2021, 5(1): 17. doi: 10.1038/s41528-021-00114-y [19] ZHAO Y, GUO X, HONG W, et al. Biologically imitated capacitive flexible sensor with ultrahigh sensitivity and ultralow detection limit based on frog leg structure composites via 3D printing[J]. Composites Science and Technology, 2023, 231: 109837. doi: 10.1016/j.compscitech.2022.109837 [20] WAN Y, QIU Z, HUANG J, et al. Natural plant materials as dielectric layer for highly sensitive flexible electronic skin[J]. Small, 2018, 14(35): 1801657. doi: 10.1002/smll.201801657 [21] ELSAYES A, SHARMA V, YIANNACOU K, et al. Plant-based biodegradable capacitive tactile pressure sensor using flexible and transparent leaf skeletons as electrodes and flower petal as dielectric layer[J]. Advanced Sustainable Systems, 2020, 4(9): 2000056. doi: 10.1002/adsu.202000056 [22] CHOI J, KWON D, KIM K, et al. Synergetic effect of porous elastomer and percolation of carbon nanotube filler toward high performance capacitive pressure sensors[J]. ACS applied materials & interfaces, 2019, 12(1): 1698-1706. [23] 郭常波, 张鹏, 张龙, 等. 基于空心微柱介电层的柔性电容式压力传感器[J]. 电子元件与材料, 2024, 43(1): 33-39.GUO Changbo, ZHANG Peng, ZHANG Long, et al. Flexible capacitive pressure sensor based on hollow microcolumn dielectric layer[J]. Electronic Components & Materials, 2024, 43(1): 33-39(in Chinese). [24] SONG Z, LIU Z, ZHAO L, et al. Biodegradable and flexible capacitive pressure sensor for electronic skins[J]. Organic Electronics, 2022, 106: 106539. doi: 10.1016/j.orgel.2022.106539 [25] 陈续峰, 张宇, 秦亚飞, 等. 基于炭黑-钛酸钡/聚氨酯的柔性电容式压力传感器[J]. 复合材料学报, 2024, 42: 1-10.CHEN Xufeng, ZHANG Yu, QIN Yafei, et al. Flexible capacitive pressure sensor based on carbon black/barium titanate/polyurethane[J]. Acta Materiae Compositae Sinica, 2024, 42: 1-10(in Chinese). [26] 王菲菲, 彭海益, 姚晓刚. 基于多向冷冻法制备的高灵敏度柔性电容式压力传感器[J]. 复合材料学报, 2023, 40(5): 2680-2687.WANG Feifei, PENG Haiyi, YAO Xiaogang. High-sensitive flexible capacitive pressure sensor based on multi-directional freezing method[J]. Acta Materiae Compositae Sinica, 2023, 40(5): 2680-2687(in Chinese). [27] ZHAO T, ZHU H, ZHANG H. Rapid prototyping flexible capacitive pressure sensors based on porous electrodes[J]. Biosensors, 2023, 13(5): 546. doi: 10.3390/bios13050546 [28] SENGUPTA D, LU L, GOMES D R, et al. Fabric-like electrospun PVAc–graphene nanofiber webs as wearable and degradable piezocapacitive sensors[J]. ACS Applied Materials & Interfaces, 2023, 15(18): 22351-22366. [29] CUI H, LIU Y, TANG R, et al. A sensitive and flexible capacitive pressure sensor based on a porous hollow hemisphere dielectric layer[J]. Micromachines, 2023, 14(3): 662. doi: 10.3390/mi14030662 [30] LI R, PANAHI-SARMAD M, CHEN T, et al. Highly sensitive and flexible capacitive pressure sensor based on a dual-structured nanofiber membrane as the dielectric for attachable wearable electronics[J]. ACS Applied Electronic Materials, 2022, 4(1): 469-477. doi: 10.1021/acsaelm.1c01098 [31] YING S, LI J, HUANG J, et al. A flexible piezocapacitive pressure sensor with microsphere-array electrodes[J]. Nanomaterials, 2023, 13(11): 1702. doi: 10.3390/nano13111702 [32] KURUP L A, COLE C M, ARTHUR J N, et al. Graphene porous foams for capacitive pressure sensing[J]. ACS Applied Nano Materials, 2022, 5(2): 2973-2983. doi: 10.1021/acsanm.2c00247 [33] QIU J, GUO X, CHU R, et al. Rapid-response, low detection limit, and high-sensitivity capacitive flexible tactile sensor based on three-dimensional porous dielectric layer for wearable electronic skin[J]. ACS applied materials & interfaces, 2019, 11(43): 40716-40725. [34] HA K H, ZHANG W, JANG H, et al. Highly sensitive capacitive pressure sensors over a wide pressure range enabled by the hybrid responses of a highly porous nanocomposite[J]. Advanced Materials, 2021, 33(48): 2103320. doi: 10.1002/adma.202103320 [35] YE X, TIAN M, LI M, et al. All-fabric-based flexible capacitive sensors with pressure detection and non-contact instruction capability[J]. Coatings, 2022, 12(3): 302. doi: 10.3390/coatings12030302 [36] GUAN F, XIE Y, WU H, et al. Silver nanowire–bacterial cellulose composite fiber-based sensor for highly sensitive detection of pressure and proximity[J]. ACS nano, 2020, 14(11): 15428-15439. doi: 10.1021/acsnano.0c06063 [37] GARBINI J L, SAUNDERS R A, JORGENSEN J E. In-process drilled hole inspection for aerospace applications[J]. Precision engineering, 1991, 13(2): 125-134. doi: 10.1016/0141-6359(91)90503-B
计量
- 文章访问数: 12
- HTML全文浏览量: 9
- 被引次数: 0