Graphene Platelets and Their Polymer Composites: Fabrication, Structure, Properties, and Applications

Graphene oxide is extensively compounded with polymers toward a wide variety of applications. Less studied are few-layer or multi-layer highly crystalline graphene, both of which are herein named as graphene platelets. This article aims to provide the most recent advancements of graphene platelets and their polymer composites. A first focus lies on cost-effective fabrication strategies of graphene platelets - intercalation and exfoliation - which work in a relative mass scale, e.g., 5.3 g h(-1). As no heavy oxidization is involved, the platelets have high crystalline integrity, e.g., C:O ratio over 8.0, with thicknesses 2-4 nm and lateral dimension up to a few micrometers. Through carefully selecting the solvent for dispersion and the molecules for surface modification, graphene platelets can be liquid-processable, enabling them to be printed, coated, or compounded with various polymers. A purpose-designed experiment is undertaken to unravel the effect of reasonable ultrasonication time on the platelet thickness. Typical polymer/graphene platelet composites are critically examined for their preparation, structure, and applications such as thermal management and flexible/stretchable electronic devices. Perspectives on the limitations, current challenges, and future prospects for graphene platelets and their polymer composites are provided.