A highly flexible, stretchable and ultra-thin piezoresistive tactile sensor array using PAM/PEDOT:PSS hydrogel

This paper presents a highly flexible, stretchable and ultrathin piezoresistive tactile sensor array, which can be attached to a tactile display actuator array [1] without any influence on its motion. Its operational principal is based on the resistance changing of a tactile cell array prepared by blending a precise conductive polymer — Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) with Polyacrylamide (PAM) hydrogel. Through comparing the characteristics of the blended hydrogel mixed between PAM and PEDOT with different ratios 2.5:1; 3:1; 3.5:1 respectively, the 2.5:1 ratio is the appropriate sample selected as the sensor design. Then, the 12×8 tactile sensor array were fabricated by dropping the conductive hydrogel into the cavity of two electrodes cast on Sylgard 184 substrates (PDMS), which is flexible and thin — around 800μm thickness in total. Finally, a primary measuring circuit using Wheatstone Bridge with a low-pass filter, an amplifier, and a signal processing circuit are also built to demonstrate the sensor s performance successfully.