Negative normal stress differences in graphene/polycarbonate composites

Abstract

We measured the negative normal stress differences in graphene (0.5 wt. %)/polycarbonate composites during shear flow. The Peclet number in graphene/PC melt is estimated to be 105 ∼ 108, indicating the graphene sheets are non-Brownian. The negative normal stress is related with the deformations of gel-like structure of graphene sheets in PC. The storage modulus of graphene/PC composite melts approaches to a solid-like plateau in the terminal region at low concentration of 0.05 ∼ 0.70 wt. % graphene.