Interfacial behaviour of MXene-modified basalt fibres in sustainable bio-based epoxy composites

Basalt fibre (BF) composites combine mechanical performance and sustainability, but their application is limited by insufficient fibre–matrix interfacial adhesion. This study investigates the interfacial behaviour of BF with Ti₃C₂T_x MXene coating, embedded in a bio-based epoxy system, experimentally and numerically. Oxygen plasma treatment was applied to increase the hydrophilicity of BF, and a MXene nanolayer was deposited using a dip-coating technique. Scanning electron microscopy revealed a transition from a smooth BF surface to a MXene nano-roughened one. Microbond tests showed that plasma-treated fibres exhibited a 40% increase in interfacial shear strength, while combined with MXene treatment showed a 14% increase, when compared with pristine fibres. Based on the experimental results, a finite element model of an epoxy microdroplet on MXene-coated BF was developed. Numerical simulations indicated that Mode II fracture energy strongly depends on the surface treatment. Plasma treatment resulted in a 115% increase in fracture energy, while the combined treatment led to a 46% increase. The experimental and numerical framework provides detailed insight into microscale debonding mechanisms. It supports the further investigation of high-performance BF composites with tailored interfacial and electrical properties for multifunctional applications.