Dual Stimuli-Responsive Actuation of Oriented MXene/Polymer Composite

Abstract

Soft actuators capable of programmable deformation and multimodal responsiveness are increasingly in demand for advanced platforms requiring precise motion control, environmental sensing, and remote actuation. While bilayer structures are commonly used to achieve asymmetric actuation, their discrete interfaces often lead to delamination, which can be avoided by employing a structurally continuous monolayer system. We present a scalable method for fabricating monolithic gradient Ti3C2Tx MXene/polymer composite films with directional bending actuation. An in-plane alternating current (AC) electric field applied during photopolymerization not only induces vertical nanosheet alignment but also promotes their sedimentation near the substrate. Aligned films exhibit enhanced bending performance at identical filler concentrations and controlled bending direction compared to random ones. Through structural analysis and condition-dependent tests, the dual-mode actuation mechanism was elucidated. Our actuator maintains excellent reversibility and durability under repeated infrared light and humidity stimuli. This work offers a robust platform for MXene-based soft actuators with defined anisotropy, applicable to adaptive robotics, wearable humidity sensors, and thermally responsive systems.