Nacre-Mimetic Structure\nMultifunctional Ion-Conductive\nHydrogel Strain Sensors with Ultrastretchability, High Sensitivity,\nand Excellent Adhesive Properties

Abstract

Recently, conductive hydrogels have emerged as promising\nmaterials\nfor smart, wearable devices. However, limited mechanical properties\nand low sensitivity greatly restrict their lifespan. Based on the\ndesign of biomimetic-layered structure, the conductive hydrogels with\nnacre-mimetic structure were prepared by using layered acrylic bentonite\n(AABT) and phytic acid (PA) as multifunctional “brick”\nand “mortar” units. Among them, the unique rigid cyclic\nmultihydroxyl structure of the “organic mortar” PA preserves\nboth ultrastretchability (4050.02%) and high stress (563.20 kPa) of\nthe hydrogel, which far exceeds most of the reported articles. Because\nof the synergistic effect of AABT and PA, the hydrogel exhibits an\nexcellent adhesive strength (87.74 kPa). The role of AABT in the adhesive\nproperties of hydrogels is proposed for the first time, and a general\nstrategy for improving the adhesive properties of hydrogels by using\nAABT is demonstrated. Furthermore, AABT provides ion channels and\nPA ionizes abundant H⁺, conferring a high gauge factor\n(GF = 14.95) and excellent antimicrobial properties to the hydrogel.\nAlso, inspired by fruit batteries, simple self-powered flexible sensors\nwere developed. Consequently, this study provides knowledge for functional\nbentonite filler modified hydrogel, and the prepared multifunctional\nionic conductive hydrogel shows great application potential in the\nfield of intelligent wearable devices.