mbnu FY2016 Annual Report 3.3

Figure: a) G-O aqueous dispersions at different volume concentrations are prepared by adding G-O in water. Oscillatory linear shear flow: When the concentration is less than the critical volume or mass concentration, viscous response due to the drag of the G-O sheets prevails over the elastic response. When the concentration is greater than the critical volume concentration,  elastic response due to the G-O self-aggregation prevails over the viscous response due to the drag of the clusters. Steady shear flow: When the concentration is less than the critical volume concentration, and at Peclet number Pe<1, G-O sheets are randomly oriented; while at Pe > 1 G-O sheets are oriented along the flow direction. When the concentration is greater than the critical volume concentration and at Peclet number Pe < 1, G-O are arranged in randomly oriented clusters; while at Pe > 1 clusters are broken down. Transient shear flow: Only for the concentration greater than the critical volume concentration is considered. Initially, the dispersion is arranged in randomly oriented clusters. After applying a flow at Pe > 1, clusters are broken down and G-O sheets are oriented along the flow direction. When the flow is arrested, Pe = 0, G-O sheets start to self-arrange. After sufficient resting time, G-O sheets recover the initial cluster configuration.