Paper TR-FrM5
Basal Plane Surface Functionalization of Graphene Nanoplatelets

Friday, November 14, 2014, 9:40 am, Room 303

Due to their high in-plane strength, electrical and thermal conductivity and lubricity, graphene nanoplatelets (GnP) have great potential in polymer composite and lubricant additive applications. However, to fully utilize these remarkable properties the GnPs must be functionalized in such a way as to make them attractive to the matrix in which they are embedded. Traditionally GnPs are functionalized via wet chemical methods along their edges. Because of the high surface to edge ratio, the benefits of this functionalization are limited and unfortunately functionalization of the basal plane tends to lead to degradation of the beneficial properties. Graphite-like molecules such as Pyrene have been proposed as an alternative way to increase GnP-matrix interactions. Pyrene, which can be thought of as a small graphene sheet consisting of only four rings, interacts with the surface of the GnP via dispersion forces as opposed to chemical bonding. The pyrene itself is functionalized with alkane chains or carboxylic acid groups which then interact with the surrounding matrix material. In this paper, results from molecular simulations of the interactions between functionalized pyrene molecules and graphene nanoplatelets will be presented. These simulations have been used to measure the interaction strength between GnPs and functionalized pyrene as well as to investigate the effect of the functionalized chain length on the interaction with a poly-alpha olefin based lubricant. The aim of this work is to explore mechanisms to improve stability of GnPs in lubricants such as engine oil which is dependent upon strong interactions between the GnP and the liquid matrix to prevent settling.