Programmable shape memory poly(ionic liquid) composites for integrated self-sensing actuation and adaptive fracture management

Programmable shape memory poly(ionic liquid) composites were prepared. • Composites integrate multifunctionality via network design within a single platform. • Composites exhibit shape memory, photothermal, antimicrobial and sensing performance. • BE 0.8 P 0.5 can serve as soft actuators with real-time monitoring of the process. • BE 1.6 P 0.5 can function as wearable devices for fracture management and monitoring. The progress in soft materials that intrinsically integrate actuation, sensing, and functional responsiveness is critical for advancing wearable electronics, soft robotics, and adaptive systems. Here, we report a multifunctional poly(ionic liquid) (PIL)-based composite that achieves this integration through rational molecular and network design. The composite was fabricated through UV-induced polymerization of 1-vinyl-3-butylimidazolium bromide (BVIM[Br]) and poly(ethylene glycol) diacrylate. PEDOT:PSS was incorporated to form a synergistic ionic-electronic conductive network and photothermal responsive performance. The switching temperature was programmable via precisely tailoring the polymer network architecture. Thus, the material can operate across distinct regimes from robust light-driven actuation to body-relevant conditions. The optimized composite exhibited excellent multi-stimuli-responsive shape memory behavior with high fixation and recovery ratios (>95%), rapid photothermal actuation capable of lifting 980 times its own weight, and intrinsic electromechanical coupling that allows real-time resistance feedback. At physiologically relevant trigger temperatures, the material also demonstrated intrinsic antibacterial activity (>99% inhibition), favorable cytocompatibility, and reliable strain sensing performance, supporting stable biointerface operation. Based on these properties, a fracture fixation ring was constructed, combining adaptive shape memory immobilization, localized photothermal therapy, and real-time motion monitoring within a single platform. This study establishes a generalizable strategy for designing soft materials with intrinsically coupled mechanical, electrical, and biomedical functionalities. This composite offers a versatile platform for applications spanning wearable devices, human-machine interfaces, soft robotics, and therapeutic systems. Download: Download high-res image (124KB) Download: Download full-size image