(346d) Oxygen Effect On Elastic Modulus of Graphene Oxide

Ken-Hsuan Liao, Jong-Seok Jeong, Greg Haugstad, K. Andre Mkhoyan, Chris Macosko

Chemical Engineering & Materials Sciences, University of Minnesota, Twin Cities

Characterization Facilities of University of Minnesota, Twin Cities

Graphene/polymer nanocomposites are one of the most attractive applications for graphene. Incorporation of graphene has been reported to effectively improve mechanical and electrical properties of polymers. Chemically reduced graphene from graphite oxide has been mainly used  since it appears to be the most economic production process. Different chemically reduction processes lead to various oxygen contents of the produced graphene. However, according to reported results, there is still no conclusion how oxygen content effect the elastic modulus of graphene. With this motivation, we have studied the elastic modulus of graphene oxide with various oxygen content. We used in situ AFM nano-indentation to measure the influence of oxygen on the elastic modulus of graphene oxide with various carbon/oxygen (C/O) ratios. The results show that chemical reduction (lower oxygen contents) will decrease the elastic modulus of graphene oxide. We speculate that chemical reduction of oxygen atoms of epoxy groups on graphene oxide surface will remove the bridging effect between carbon atoms, which leads to more flexible sheets.