Synthesis and Characterization of Graphene-Based Inks for Spray-Coating Applications

Conductive inks made of graphene-like materials have attracted significant attention due to their extraordinary electrical properties. In this study, three different types of graphene-like materials, namely, graphene foam (GF), graphite nanoplatelets (GNPs) and synthetic graphite (SG), are utilized to fabricate conductive inks for printable flexible electronics applications. The results show that GF exhibits the highest surface area and pore volume, while GNPs and SG display large lateral sizes, highly crystalline structures and high-quality particles. In addition, the quality of the sprayed patterns are mainly influenced by the properties of graphene-based inks. The properties of conductive inks made from various graphene-like materials, including the viscosity, contact angle and surface energy, are investigated. The viscosity and contact angle of the conductive inks increase markedly with increasing filler loadings in a polyester varnish (PV) binder. Based on the electrical conductivity of unfilled PV, the conductive ink made of GNPs exhibits a 186% improvement in electrical conductivity at 10vol% filler loading compared to those of 40% and 10% shown by SG and GF, respectively.