Electronic skins (E-Skins) designed to emulate sensing properties of human skin, have been explored for a variety applications including smart prosthetics, human machine interfaces, and wearable health monitoring devices. In particular, biomimetics has led new concepts in material designing and device structure manipulation with the aim of mimicking tactile sensing features of human skin intelligently. However, most of the e-skin architectures developed so far are ultrasensitive in low pressure (0-10 kPa) regime but become almost insensitive beyond this narrow pressure sensing range, which limits their use for practical applications.
In this talk, we present a novel synthetic cellular-structured ionic polymer composite inspired from structural and mechanotransduction features of living cell and explore its potential application in piezo-capacitive e-skin device. The key innovation of our work is our material design, where ionic liquid confined silica microstructures (artificial intracellular) well dispersed in thermoplastic elastomer chains (artificial extracellular) enabling fascinating structural, mechanical, and functional properties at molecular level. Structure-derived confinement of ionic species in silica matrix under no force condition and subsequent stimulus driven squeezing-out of ions through intrinsic silica-thermoplastic elastomer nanochannels seems to emulate structural and functional features of living cell in a more pronounced way that resulted in high pressure sensitivity of the e-skin device consistently in both low-pressure (42-48 kPa-1 (0-10 kPa)) and medium/high pressure regimes (5-7 kPa-1 (50-100 kPa)), enabling scope of gentle touch to the object manipulation tasks in robotics. Considering both the unprecedented sensitivity and wide pressure sensing range achieved in single device architecture, the pressure sensing e-skin developed in this work is one of the highest among all reported pressure sensors to the date.
We believe that the experimental results presented here provides an empathetic solution to the low sensitivity, narrow pressure sensing range and complex device architecture related issues associated with e-skins developed so far.