Controllable lateral contraction and mechanical performance of chemically reduced graphene oxide paper

Graphene paper assembled from graphene oxide (GO) sheets has attracted great attention due to the intriguing physical and chemical properties. Here, we discovered that the size stability and mechanical performances of reduced graphene oxide (RGO) papers obtained by chemical reduction of the vacuum filtered GO papers are strongly dependent on the pH value of the starting GO suspensions. Moreover, it is found that RGO paper obtained from GO suspension with pH = 7 demonstrated superior performance of both flexural endurance and electrical conductivity. By investigating the structural differences of the prefabricated GO papers and their swelling behaviors during reduction, as well as the unlike microstructures of the obtained RGO papers, we interpreted the origin of the pH-mediated controllable contraction and mechanical performance of RGO papers. This study suggests a simple strategy for controlling the size stability, mechanical performance and electrical conductivity of RGO paper.