Porous hydrogel micropressure sensors enabled by nanocellulose microgel stabilized high internal phase pickering emulsion templates

Abstract

Lightweight soft hydrogels are ideal materials for next-generation sustainable wearable flexible electronics. However, achieving an optimal combination of high flexibility, high sensitivity, and micropressure sensing presents significant challenges. Introducing porous structures has emerged as a promising approach to enhance the micropressure responsiveness of hydrogels. This study proposes a highly stable high internal phase Pickering emulsion (HIPE) template stabilized by nanocellulose microgels to fabricate ultrasoft porous hydrogels with high porosity. By regulating the stability and microstructure of the HIPE, the porous hydrogels achieved synergistic improvements in high deformability, subtle pressure detection, and enhanced sensitivity. The porous hydrogels prepared by combining HIPE with an acrylic acid/acrylamide system exhibited low Young’s modulus (11 kPa), high porosity (75.9 %), extensive tensile strain range (0–1368 %), enhanced sensitivity coefficient (133.18 kPa⁻¹) under subtle pressures (0–230 Pa), and excellent skin-adhesion capabilities. The integrated porous hydrogel sensors enabled precise detection of micropressure signals (e.g., pulses and wrist movements) under various motion states. This study provides a novel strategy for improving micropressure detection and sensitivity in hydrogel-based flexible micropressure sensors, highlighting their immense potential for diverse applications in flexible electronics.