Moiré superlattice-driven bionic hydrogel robot with programmable multifunctionality

The flexibility and intelligent responsiveness of hydrogel robots offer great potential for exploration in narrow and complex environments. However, the integration of sensors with hydrogel robotic bodies remains challenging. Inspired by marine organisms, this paper presents an anemone-like light-driven hydrogel robot (ALHR) for directional infrared radiation detection. We fabricated via ultrasonic-assisted stacking a black phosphorus/tungsten disulfide (BP/WS2) moiré superlattice, showing high dual-mode photothermal-photovoltaic conversion performance. Based on this, a composite poly(N-isopropylacrylamide) (PNIPAM) hydrogel was used to build the base plate and tentacle structures of the ALHR. Specific illumination was found to trigger the photothermal effect of the BP/WS2 moiré superlattice, allowing for directional movement. When the tentacles retract and contact the bottom electrode, photocurrent signals are conducted for infrared detection. The ALHR can work in specialized spatial environments, providing a promising method for early overheating fault identification in equipment. This study proposes a universal design framework for multifunctional hydrogel robots by integrating responsive units with driving units to leverage the synergistic effects of multiple materials. The integration of sensors with hydrogel robots remains challenging. Here, the authors report the realization of anemone-like light-driven hydrogel robots integrating 2D black phosphorus/tungsten disulfide moiré heterostructures, enabling dual-mode photothermal-photovoltaic response and light-induced directional movement.