Reduced graphene oxide coated polyurethane composite foams as flexible strain sensors for large deformation

Abstract

Combining graphene composite with three-dimensional structure is an effective strategy to avoid the agglomeration of graphene nanosheets and significantly enhances the properties of composite at low graphene content. In this work, reduced graphene oxide coated polyurethane composite foams (RPFs) with different pore sizes were prepared by a simple and economical self-assembly method. The RPFs are found to have good structural integrity and excellent flexibility, with a remarkable ability to withstand large deformation of 90% and 3 orders of magnitude decrease of electrical resistance. The RPF composite with higher density and smaller pore size exhibits better elasticity and responsive piezoresistivity. The resistance-time curves of RPFs in compression and bending modes exhibits a quick response of loading and release procedures by 0.10 s and 0.74 s in compression, 1.14 s and 0.91 s in bending, respectively, showing a good potential application of flexible and highly sensitive strain sensors for large deformation.