Bimorph Soft Actuators Based on Isostructural Heterogeneous Janus Films

Bimorph soft actuators, traditionally composed of two materials with distinct responses to external stimuli, often face durability challenges due to structural incompatibility. Here, we propose an alternative design employing free-standing, isostructural heterogeneous Janus (IHJ) films that harmonize stability with high actuation efficiency. These IHJ films were fabricated through a vacuum self-assembly process, consisting of Ti3C2Tx MXene nanosheets and hybrid graphene oxide (GO)-biomass bacterial cellulose (BC), with a well-matched two-dimensional lattice structure. The special structure of the film, featuring continuous laminar layers and one-dimensional (1D) BC nanofibers intertwining with two-dimensional (2D) GO and MXene nanosheets, promotes interlayer slip during deformation, enhancing stability and deformability. The IHJ film responds swiftly to electrical stimuli, humidity, and light, causing layer expansion or contraction through the rapid absorption and release of water molecules and enabling controllable actuation. The IHJ film can be utilized as actuators in various soft robotic applications, such as a "flower robot" under electrical stimulus, a "passive switch" under humidity, and a "worm robot" under infrared lamp exposure. The design of the IHJ film achieves large-scale deformation, low power consumption, high responsiveness, and enhanced real-time sensing capabilities, representing an important development in soft actuator design.