Anticreep and Antiswelling Sensor Hydrogel Inspired by Human Pressure Tactile for Food Detection

Abstract

Achieving biomimetic human pressure tactile perception for food detection has been a primary objective in the development of sensing hydrogels. However, the inherent challenges associated with the creeping and swelling behaviors of hydrogels have significantly impeded progress. In this study, we introduce a hydrogel system engineered with a multiscale energy dissipation structure to enable flexible sensing and detection that emulates human pressure tactile. At the molecular scale, the supramolecular interactions, including hydrogen bonding and ionic interactions among macromolecular segments, are incorporated into the hydrogel matrix. At the nanoscale, an elastic spherical mesh structure is integrated to reinforce the hydrogel network. When subjected to external forces, the hydrogel effectively resists creep by absorbing external forces and storing energy. The PAASi hydrogels exhibit remarkable creep resistance (withstanding 1000 compression cycles without deformation), swelling resistance (no volume change after soaking), and high sensitivity (1.16 kPa^–1). The sensing systems utilizing PAASi hydrogels have been successfully applied to evaluate the freshness of fruits and the water content in sea cucumbers. This work has guiding significance for irritant response hydrogels in food detection.