Integrated conductive hydrogel soft actuators for remote photothermal actuation and multimodal self-sensing

Conductive hydrogels are promising materials for advanced applications in artificial muscles, biomimetic soft robotics, and wearable electronics. However, the simultaneous realization of rapid reversible actuation, superior mechanical robustness, and high-resolution multimodal sensing remains a formidable challenge. Herein, we present a multifunctional hydrogel based on thermos-responsive poly(N-isopropylacrylamide) (PNIPAM), reinforced via acrylamide (AM) copolymerization and polyvinyl alcohol (PVA) network integration, which synergistically enhance mechanical strength and toughness. The incorporation of MXene nanosheets endows the hydrogel with stable, repeatable, and ultrasensitive piezoresistive sensing performance. Moreover, the hydrogel exhibits excellent photothermal actuation under near-infrared (NIR) irradiation, enabling remote, light-actuation deformation coupled with real-time self-sensing. To enrich its sensing modalities, a piezoelectric composite layer composed of poly(vinylidene fluoride-trifluoroethylene) and barium titanate [P(VDF-TrFE)/BTO] is integrated, allowing simultaneous detection of strain amplitude, movement direction, and velocity. As a proof of concept, a biomimetic octopus predation system was constructed, showcasing the potential of this integrated actuator-sensor platform for intelligent soft robotic systems.