Phase-Locked Dynamic Silyl Ether Metathesis Enabled Mechanically Robust, Self-Healing Polyurethane for Multifunctional Smart Textiles

Abstract

To reconcile mechanical robustness with self-healing in polyurethane (PU) elastomers for durable smart textiles, this study presented a “phase-locked dynamic silyl ether metathesis” strategy. A series of hybrid PU elastomers were synthesized by incorporating double-decker silsesquioxane (DDSQ) capable of dynamic Si−O bonds, along with carbohydrazide containing sextuple hydrogen bonds, as dual chain extenders. With a hydrogen-bonding degree exceeding 85%, the resulting elastomers formed a distinct microphase-separated structure, which enabled a thermally responsive “lock−unlock” mechanism. At service temperature, dynamic Si−O bonds remained “locked” within hard domains, where rigid DDSQ cages acted as nanoreinforcements, endowing the elastomer with outstanding mechanical strength (36.6 MPa) and toughness (116.0 MJ/m3). Upon heating, the dissociation of hydrogen bonds “unlocked” the Si−O bond exchange, facilitating excellent self-healing efficiency (>97%). Furthermore, a multifunctional smart textile was fabricated by dip-coating a pristine textile with the optimized PU and fluorinated MXene. The F-MXene coating provided photothermal heating, strain sensing, and antibacterial activity, while the PU matrix ensured stable dispersion and strong adhesion of the F-MXene nanosheets. Moreover, the PU matrix enabled self-healing functionality, restoring both surface wettability and MXene-derived properties after damage. Combined with retained waterproofness and breathability, this multifunctional textile was well-suited for motion monitoring and human−machine interaction, offering a promising platform for next-generation wearable devices.