<i>Hofmeister</i> effect regulated gel iontronic sensors for wide-range pressure perception

Abstract

<p>Flexible pressure sensors, vital for medical, human-machine interaction, and intelligent recognition applications due to their high-sensitivity, excellent-linearity, and broad-pressure response, face challenges in achieving a harmonious balance among these attributes. Inspired by the gradient modulus in human skin layers, we proposed a pioneering method to adjust the gradient elastic modulus of amino trimethylene phosphonic acid (ATMP)-assisted polyvinyl alcohol (PVA) hydrogel through the <i>Hofmeister</i> effect, introducing micro-pyramid electrodes. This innovative approach successfully constructs a bio-gradient gel iontronic sensor (BGGITS) with an ultra-wide-range perception. The BGGITS exhibits a linear high-sensitivity of 700 kPa^-1 within a broad-pressure detection range of up to 800 kPa. The composite design, integrating gradient gel and microstructure electrodes, demonstrates exceptional pressure resolution and mechanical stability. This biomimetic skin pressure sensor holds promise for achieving linear high-sensitivity across a broader pressure range simultaneously and may find applications in electronic skin for health monitoring and tactile perception in the future.</p>