A nano-enhanced photocurable polyacrylamide/titanium dioxide/β-cyclodextrin (PAM/TiO₂/β-CD) composite ionogel was fabricated via a multi-component synergistic strategy. TiO₂ nanoparticles act as physical crosslinking points and Lewis acid active sites for mechanical reinforcement and extra ion transport channels, while β-CD realizes uniform TiO₂ dispersion, promotes ionic liquid dissociation, and relaxes the polymer network. Notably, the conductivity of the PAM/TiO₂/β-CD ionogel is 617.76% higher than that of the pristine PAM ionogel (4.11×10^-3 S m^-1), and the optimized ionogel (5 wt% TiO₂, 2 wt% β-CD, 20 wt% [EMIM][TFSI]) achieves a high ionic conductivity of 2.95×10^-2 S m^-1, an ultrahigh elongation at break of 1273%, and excellent environmental stability (a mass change < 2.8% after 2 weeks of open-air exposure). Based on this ionogel, a resistive strain sensor (a linear sensing range of 100 - 1000% with a gauge factor of 0.765) and an electric double-layer pressure sensor (10.69×10^-3 kPa^-1 sensitivity) with superior sensing performance are constructed. An intelligent glove integrated with these sensors is further developed, realizing accurate finger curvature detection, gesture recognition, and palm pressure mapping for human-machine interaction. This work provides a feasible strategy for high-performance ionogels and their applications in flexible electronics.

Flexible underwater vehicles with high maneuverability, high efficiency, high speed, and low disturbance have shown great application potential and research significance in underwater engineering, ocean exploration, scientific investigation and other fields. The research and development of flexible stimulus-responsive actuators is key to the development of high-performance underwater vehicles. At present, the main drive methods for underwater devices include electric drive, magnetic drive, light drive, thermal drive, and chemical drive. In this work, the research progress of stimuli-responsive actuators in water environment is reviewed from the stimuli-responsive patterns, functional design, fabrication methods, and applications in water environment. Firstly, the actuation principles and characteristics of electro-responsive, magnetic-responsive, photo-responsive, thermo-responsive actuators, and chemically responsive actuators are reviewed. Subsequently, several design requirements for the desired flexible actuators are introduced. After that, the common fabrication methods are summarized. The typical application of the stimuli-responsive actuator in the water environment is further discussed in combination with the multi-stimuli-responsive characteristics. Finally, the challenges faced by the application of stimuli-responsive actuators in the water environment are analyzed, and the corresponding viewpoints are presented. This review offers guidance for designing and preparing stimulus-responsive actuators and outlines directions for further development in fields such as ocean energy exploration and surface reconnaissance.