Rational design of a porous nanofibrous actuator with highly sensitive, ultrafast, and large deformation driven by humidity

Humidity-responsive bilayered actuators which can dynamically change their shapes under humidity gradients, have recently motivated significant interest in a wide variety of emerging fields, including artificial muscles, intelligent sensors, and smart devices. However, this kind of actuators frequently suffer from slow responsiveness, prolonged actuating period, and small deformation, which is due to the dense structure hindering the diffusion of water molecules. Herein, we employ a simple programmable electrospinning approach to fabricate a highly porous polyvinyl alcohol/polyvinyl butyral (PVA/PVB) bilayered actuator for achieving excellent humidity-triggered deformation. Benefiting from the differential affinity of the two layers to water and the elaborately structural design, the porous bilayered actuator exhibits superior actuating performance in response to humidity gradient. Briefly, only 283 ms is needed for driving the shape change, and the whole deformation merely requires 10 s; besides, large bending amplitude with the curvature of 11.2 cm-1 is achieved, and the shape deformation process can be repeated at least 30 times without fatigue. Finally, we demonstrate the porous nanofibrous actuator can be used as artificial plants to perform opening and closing motions and a self-driven detector for monitoring humidity in real-time.

Automated summary

A highly porous PVA/PVB bilayered actuator with excellent humidity-triggered deformation performance was fabricated using a simple programmable electrospinning method. The porous bilayered actuator exhibited superior actuating performance in response to humidity gradient.