Enabling Controlled Sliding and Multi‐Modal Sensing in an Anti‐Swelling, Muscle‐Inspired Hydrogel via Multiple Cross‐Linking

ABSTRACT

The development of hydrogel‐based flexible sensors is hindered by their inherent swelling and performance degradation in physiological environments. Inspired by the structure‐function integration of natural muscle, a biomimetic multifunctional smart hydrogel with a triple‐crosslinking structure via polyvinyl alcohol (PVA) crystalline domains, dynamic borate ester bonds, and high‐density hydrogen bonds among phytic acid, PVA, and hydroxypropyl cellulose is designed in this study. The network ensures robust structural integrity and long‐term stability while maintaining flexibility, exhibiting a swelling ratio of only 2.5% in simulated body fluid (SBF) after 40 days. Embedded MXene nanosheets serve as nano‐reinforcers, electronic conductive pathways, and photothermal converters, enabling near‐infrared (NIR)‐triggered reversible modulation of lubrication and electrical properties of the hydrogel. The obtained hydrogel demonstrates a stable ultra‐low friction over extended friction periods (10 h) and exhibits a unique capability for synchronous monitoring of thermal, mechanical, and frictional stimuli through a single resistance signal. This design provides a promising platform for advanced applications in biomimetic articular cartilage, smart wearable interfaces, and adaptive soft robotics.