Superelastic and large-range pressure sensor with hollow-sphere architectures for wearable electronic skin

It is challenging to manufacture pressure-sensitive devices that possess the characteristics of the linearly sensitive regime, high reliability, and large-range pressure detection for the development of artificial intelligence products. Here, a facile approach is proposed to fabricate piezo-resistive sensors with well-defined hollow-sphere architectures based on thermoplastic expandable microspheres (TEMs) by the physical foaming process. The expanded TEMs can maintain complete spherical shell structure after heating treatment and withstand large pressure without rupture, endowing the composite films with excellent mechanical performances and structural stability. Configured as a pressure sensor, the device exhibits good linearity (Adj.R-2 = 0.998) at a wide pressure range (10-1300 kPa), fast response time (similar to 80 ms) and excellent reproducibility (similar to 20 000 cycles). Furthermore, by an efficient scalable fabrication process, a large-area integrated pressure sensor array with excellent sensing performance is demonstrated. This device facilitates wide-range pressure detection for a broad spectrum of applications, including gait monitoring, running speeds measurement, dynamic monitoring of plantar pressure distribution and large area space pressure mapping, which highlights the potential utilization in wearable electronic skin.