A Flexible and Self-Powered Chitosan-BaTiO₃Composite Pressure Sensor for E-Skin Applications

Abstract

Flexible, sensitive, and self-powered pressure sensors that can mimic tactile sensing of the human skin are the subject of research and development in various applications including electronic skin (e-skin), prosthetics, and soft-robotic applications. However, current state of the art pressure sensors are typically not fully conformable, requiring external power, and are generally limited in sensitivity. There is a critical need for innovative materials for the fabrication of self-powered pressure sensors that are high in sensitivity and mechanical flexibility. In this research, a piezoelectric nanocomposite-based pressure sensor fabricated using hybrid chitosan-BaTiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>nanoparticles (NPs) is presented. The sensor exhibits high sensitivities of 238 mV/kPa and 1705 mV/Hz, excellent cyclic stability greater than 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> cycles, and superior biocompatibility. The results show that there is a significant enhancement in both pressure and frequency sensitivity of nearly 10-fold and 6-fold respectively, compared to pure chitosan film. This is due to the higher piezoelectric coefficient (d33=13 pC/N) of the composite, around double. This proposed hybrid organic-inorganic composite material lays a robust foundation for future development of high-performance sensors for next generation prosthetics and soft robotic applications.