Enhanced viscoelastic properties of graphene oxide membranes

Viscoelastic materials having high loss factor are receiving enormous importance in damping applications. In this report, several layers of graphene oxide (GO) stacked thick membranes are tuned for their viscoelastic properties, and studied the role of intercalated loosely bound water in deciding their damping ratios (tan delta, ratio of loss modulus to storage modulus). The loosely bound water present inside GO membranes, where the membranes are developed using flow assisted filtration, is removed by ethanol and diethyl ether based room temperature solvent drying technique to study the dynamic mechanical behaviour of the resultant membranes. A huge enhancement in tan delta (>160%) is observed in water removed GO membranes without compromising on its storage modulus, indicating the critical role of water in GO's viscoelastic properties. The in situ tan delta variation of GO paper immersed in ethanol bath is also studied using submersible clamp experiments in dynamic mechanical analyser, where the GO paper has undergone a dewetting phenomenon. These studies show the tunability in the viscoelastic properties of GO macroscopic structures by solvent assisted room temperature intercalation/de-intercalation techniques. (C) 2017 Elsevier Ltd. All rights reserved.