2019-12-29

Flexible and Super-Sensitive Moisture Responsive Actuators by Dispersing GO into Three-Dimensional Structures of Nanofibers and Silver Nanowires

Abstract:Smart actuator with excellent flexibility, sensitive responsiveness, large scale bending-deformation and rapid deformation-recovery performance has been sought after by researchers. Two-dimensional graphene oxide (GO) is considered as an ideal candidate for humidity responsive actuators due to its excellent moisture sensitivity. Herein, a flexible membrane-based actuator was prepared by evenly dispersing GO sheets into three-dimensional network formed by one-dimensional PVA-co-PE nanofibers (NFs) and silver nanowires (AgNWs). The three-dimensional interlaced pore structure of the AgNWs/NFs/GO composite membrane ensured its larger contact area, faster moisture exchange rate, and large bending deformation under moisture stimulation. In addition, a new explanation on the spatial distribution of adsorbed water molecules and their actuating effect on the bending behaviors of composite membranes are proposed. The adsorbed water lies between the inter-layer and surface layer of the composite membrane. The inter-layer water molecules make the film volume expand, resulting in a large bending angle of the membrane. On the other hand, the water on surface layers of the membrane only leads to the change in film weight, has little effect on the bending behavior. Moreover, to make the soft actuator more practical and multi-functional, a conductive AgNWs-NFs/GO bilayer membrane-based actuator was prepared by layered spraying silver nanowire on NFs/GO membrane, which can be directly used in switching control circuits. The novel flexible membrane-based actuators are of great significance for the soft robot and intelligent control system in the future.

Xiang Chenxue, et al. Flexible and Super-Sensitive Moisture-Responsive Actuators by DispersingGraphene Oxide into Three-Dimensional Structures of Nanofibers and SilverNanowires. ACS Applied Materials & Interfaces, 2020,12,3245-3253.