Microphase-Separated Hydrogels With Low Hysteresis and High Damping for Flexible Protection and Electronics

In recent years, many synthetic hydrogels with high mechanical strength have been developed, while few combine elasticity and damping properties like living tissues. The intrinsic contradiction between toughness and resilience makes it challenging to design gels with both effective dissipation and shape maintenance. To address this, this study uses ultrasound-based microreactor technology to fabricate a microphase-separated dual-network hydrogel. The hydroxy-terminated polydimethylsiloxane (PDMS-OH) and tetraethyl orthosilicate (TEOS) are dispersed in a polyvinyl alcohol (PVA) solution, and ultrasound cavitation is used to trigger catalyst-free PDMS crosslinking into spherical networks (Network I). Then, a PVA physical crosslinking network (Network II) is formed during freeze-thaw cycles, creating a dual-network PVA / PDMS hydrogel. The PDMS microspheres' bimodal size distribution significantly enhances the hydrogel's damping performance, achieving a loss factor (tan δ) of 0.51, outperforming conventional hydrogels. Molecular dynamics simulations reveal that such particle distribution increases friction between PVA and PDMS networks, boosting energy dissipation. The hydrogel also exhibits excellent elasticity, recyclability, and biocompatibility, which shows great potential applied as flexible electronic skin and damping materials.