In Situ Growth of Raspberry-Like Polymer Microspheres on Carbon Fiber Surfaces Improves Interfacial Strength and Mechanical Properties of Composite

Inspired by bionic surface design principles, this study developed a one-step method to deposit thiol-isocyanate polymer microspheres on dopamine-treated carbon fiber surfaces, creating a raspberry-like surface architecture. The bioinspired structure serves as both physical and chemical “bridges” between carbon fibers and epoxy resin, while simultaneously enhancing the chemical activity, mechanical interlocking effect, and wettability of the fiber surfaces. Compared to untreated samples, the modified composites exhibited 63.11% improvement in interlaminar fracture toughness, with impact strength and tensile strength increasing remarkably by 167.55% and 73.59%, respectively. Furthermore, systematic investigation of the interfacial reinforcement mechanisms and energy dissipation modes was conducted through comprehensive fracture morphology analysis.