A hydrogel based on the synergistic effect of layered hydroxides and hydroxyethyl cellulose for flexible strain sensors

As a core functional component in wearable electronics and intelligent human-computer interaction, flexible hydrogel sensors have become a prominent research hotspot in the field of flexible electronics. However, conventional hydrogels generally suffer from critical limitations such as insufficient mechanical strength and poor sensing stability, which make them difficult to satisfy practical requirements under high-strain scenarios. In this work, a synergistic strategy of flexible chain interpenetration and inorganic node crosslinking is proposed to fabricate a composite hydrogel (PHMAL x). Hydroxyethyl cellulose (HEC) flexible interpenetrating chains are used as the functional component and Mg/Al/Li-LDHs as the two-dimensional multifunctional crosslinking nodes, a multiple dynamic crosslinking system based on hydrogen bonds and coordination interactions is constructed. Mechanical tests demonstrate a fracture strain of 1815% and strength of 4.16 MPa, with excellent anti-fatigue stability retained even after 1000 cycles. The hydrogel-based sensor exhibits piecewise high sensitivity across a wide strain range (GF 4 = 10.53), with fast response (310 ms) and stable signals, enabling accurate identification of sound vibration and handwriting pressure signals. This study provides a new paradigm for the molecular design of high-strain flexible hydrogel sensors, with various applications in intelligent handwriting recognition, voice perception, and flexible human-machine interaction.