π - π interaction between carbon fibre and epoxy resin for interface improvement in composites

This paper reports on a new biomimetic method for modifying carbon fibre surface aiming to improve the bonding between the fibre and an epoxy resin system. Inspired by the composition of adhesive proteins in mussels, dopamine was utilised in the process that was allowed to be self-polymerised onto the carbon fibre surface via π-π interaction to form a nano-thin surface-adherent polydopamine (PDA) layer. Graphene oxide (GO) was also grafted on the carbon fibre to increase interfacial strength of the composites. The fibre surface treatment and modification were performed at ambient temperature, which is non-damaging to the fibre. The chemical deposition and functional groups on the fibre were characterised by X-ray Photoelectron Spectroscopy, while the chemical structure of solution and fibre were investigated by Raman Spectroscopy. Micro-bond tests showed that the fibre/resin interfacial shear strength (IFSS) was increased by almost 70%, while the tensile strength of the GO-PDA carbon fibre improved by approximately 80%. The research indicated that π-π interaction-based fibre modification has the potential of improving crack resistance of fibre reinforced polymer composites, preventing or delaying matrix cracking and delamination that can affect their fatigue performance.