Facile Strategy for Preparing Crosstalk-Free and Stabilized Flexible Pressure Sensing Array with Inverted Micropyramids on a Substrate

Abstract

Flexible pressure sensing arrays exhibit broad application prospects in many emerging fields. Challenges remain in fabricating crosstalk-free, stabilized, and large-area pressure sensing arrays through scalable and low-cost methods. Herein, a facile strategy is proposed for preparing an electrically isolated flexible pressure sensing array (EIFPSA) by simply rubbing a Au-sprayed thermoplastic polyurethane substrate surface with inverted micropyramids. The inverted micropyramids on the rubbed sensing substrate are electronically isolated from each other, and the nonconductive ridges can prevent the current flow across adjacent sensing units. This enables the EIFPSA to have crosstalk-free performance in both flat and bent states and accurately identify the spatial pressure distribution of an object. Meanwhile, the sensing units in the EIFPSA exhibit a low zero drift without pressure and good signal stability and repeatability to respond to both static and dynamic pressures. The sensing units also exhibit good durability and sensitivity retention during cyclic compression/release testing. Specifically, there is only a slight reduction in the sensitivity after 10,000 cycles. As a proof of concept, a flexible Braille reader consisting of a data acquisition system and machine learning model is constructed to demonstrate a successful application of the EIFPSA in tactile sensing systems with a multipoint recognition capability without crosstalk.