Super-sensitive hydrogel force sensor enhanced by surface microstructure strategy

MA Yonggang; WANG Yipeng; SU Minglong; LI Xinyuan; BU Yangzhou; LIU Hu; ZHANG Dianbo

doi:10.3969/j.issn.1671-6906.2025.04.008

Abstract：Due to their exceptional elasticity,extensive strain range,convenient functionalization,and com-mendable biocompatibility,hydrogel-based force-sensitive sensors are regarded as one of the most valuable categories of flexible force-sensitive sensors.However,the intrinsic ionic conductivity properties of hydrogel materials,along with the variations in their response mechanisms,often result in reduced responsiveness and sensitivity in conductive hydrogel-based force sensors,thereby significantly limiting their application pros-pects.To address this critical scientific issue,this study employed a template method to fabricate PCA ionic conductive hydrogels featuring diverse micro-pillar structures on their surfaces,utilizing them as the respon-sive medium to construct capacitive hydrogel pressure sensors.Through an investigation into the effects of mi-crostructural spatial distribution and height on the sensor's response performance,it was found that the sen-sor's sensitivity markedly increased with a decrease in the duty cycle,and an increase in microstructure height also substantially enhanced the sensor's sensitivity.The developed micro-structured PCA ionic conductive hy-drogel sensor exhibited an exceptionally wide applicable stress range(0.05～1100 kPa),with a capacitance response at 100 kPa stress that was 39.7 times greater than that of a planar sensor.Furthermore,it demon-strated outstanding stability and fatigue resistance(19.8 kPa,5000 cycles),enabling reliable monitoring of various loads,including static and impact forces.The microstructure design strategy and its corresponding re-sponse mechanism provide valuable insights for the advancement of a new generation of high-performance hy-drogel-based force-sensitive sensors.