Surface Functionalization of Graphene with Polymers for Enhanced Properties

Graphene, a single-atom-thick sheet of hexagonally arrayed sp2 bonded carbon atoms, has been under the spotlight owning to its intriguing and unparalleled physical properties [1]. Because of its novel properties, such as exceptional thermal conductivity, [2] high Young’s modulus, [3] and high electrical conductivity,[4] graphene has been highlighted in fabricat‐ ing various micro-electrical devices, batteries, supercapacitors, and composites [5, 7]. Espe‐ cially, integration of graphene and its derivations into polymer has been highlighted, from the point views of both the spectacular improvement in mechanical, electrical properties, and the low cost of graphite [8, 9]. Control of the size, shape and surface chemistry of the reinforcement materials is essential in the development of materials that can be used to pro‐ duce devices, sensors and actuators based on the modulation of functional properties. The maximum improvements in final properties can be achieved when graphene is homogene‐ ously dispersed in the matrix and the external load is efficiently transferred through strong filler/polymer interfacial interactions, extensively reported in the case of other nanofillers. However, the large surface area of graphene and strong van der Waals force among them result in severe aggregation in the composites matrix. Furthermore, the carbon atoms on the graphene are chemically stable because of the aromatic nature of the bond. As a result, the reinforcing graphene are inert and can interact with the surrounding matrix mainly through van der Waals interactions, unable to provide an efficient load transfer across the graphene/ matrix interface. To obtain satisfied performance of the final graphene/polymer composites, the issues of the strong interfacial adhesion between graphene–matrix and well dispersion of graphene should be addressed.