One-Step Preparation of Highly Conductive Sandwich-Structured Hydrogels for Multifunctional Sensors

Based on the unique structure and performance advantages, sandwich-structured hydrogels have broad application prospects in the field of electrochemical devices. However, the sandwich-structured hydrogels still face the preparation problems of a layer-by-layer construction process and complicated operation method. In this paper, a one-step preparation of sandwich-structured hydrogels with adjustable inner layer thickness was realized, wherein the inner layer of the hydrogel was enriched by PEDOT:PSS, and the outer layer of the hydrogel was polymerized by acrylamide (AM) and zwitterionic monomer (SBMA). By adjusting the content of AM and SBMA, the enrichment of PEDOT:PSS could be affected, achieving the regulation of the inner layer thickness on conductivity. The introduction of glycerol (GL) into the outer layer of the sandwich-structured hydrogel imparted excellent environmental stability to the hydrogel. Therefore, a sandwich-structured hydrogel with high conductivity (511.29 ms/cm), significant deformability (1720%), and excellent environmental stability was obtained. The sandwich-structured hydrogel could not only be used as wearable sensors to detect human movement over a large temperature range of −20 to 60 °C but could also be woven into flexible fabric sensors for position sensing and Morse code transmission, showing promising applications in the field of multifunctional sensing.