Conductive hydrogels with HPC additions for humidity sensing and temperature response

With the rapid development of intelligent electronic technology, there have been increasing interests and demands of wearable sensors. In this emerging field, some issues of sensing materials are still need to be well-addressed, such as inadequate flexibility, poor biocompatibility, and delamination of conductive components, etc. In this study, a composite ion-conductive hydrogel with incorporated hydroxypropyl cellulose (HPC) was prepared. This composite hydrogel maintains excellent mechanical properties and biocompatibility. Moreover, the hydrogel exhibits zero crosstalk good humidity sensing as well as temperature responsiveness, and effectively avoid signal crosstalk. The hydrogel can accurately detect environmental humidity changes and real-world scenarios like oral respiration through variations in current. Additionally, it can respond to external temperature changes through transparency alterations, while retaining the strain-sensing capabilities of conductive hydrogels, enabling self-adhesive stress–strain sensing. Notably, HPC forms a network structure within the hydrogel system, leveraging its hydrophilic surface groups to enhance the humidity sensing performances. This research explores the structural distribution of HPC within the hydrogel system, offering a novel strategy for the development of HPC-added hydrogel sensors, which hold significant potentials for applications in flexible wearable devices.