Multifunctional anti-swelling hydrogel with high stretchability and adhesion for wearable flexible sensors

Abstract

Hydrogels have properties such as softness and stretchability, making them widely used in smart wearable electronics. However, hydrogels tend to swell underwater, limiting their application scenarios. This work is based on chitosan (CS) and a copolymer (AA-co-SBMA) consisting of acrylic acid and [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide, introduced tannic acid (TA), metal ion Al3+, and the conductive polymer poly (3,4-ethyl-enedioxythiophene) /poly (styrene sulfonate) (PEDOT: PSS), ACTA-SP hydrogels were prepared. This multifunctional hydrogel exhibits outstanding anti-expansion properties in various solution environments. Meanwhile, it has underwater adhesion to various substrates and excellent tensile strength (1072%). In the field of sensor applications, this hydrogel can achieve a wide detection range of 0-500% and shows a high strain coefficient of GF≈6.66. It is notable that ACTA-SP hydrogel can conduct precise, continuous and real-time dynamic monitoring of human movement postures and transmit command information via Morse code. This study provides an innovative approach to multifunctional hydrogel underwater wearable sensors and expands the prospect of hydrogel applications in the direction of flexible wearable devices.