Enhanced interfacial strength of hierarchical fiberglass composites through an aramid nanofiber interphase

Interfacial adhesion in fiber reinforced composites is a critical factor for their mechanical performance in structural applications. As nanomaterials continue to rise in prominence, the use of nanostructured interphases has grown to become a viable technique to reinforce the fiber-matrix interface of fiber reinforced polymer composites. Here, a polymeric interphase consisting of aramid nanofibers (ANFs) is introduced on Poly(diallyldimethylammonium chloride) (PDDA) coated fiberglass through electrostatic adsorption. The simple and rapid coating technique considerably roughens the inorganic fiber surface, while enriching it with polar functional groups that are capable of chemically bonding with the matrix, all while preserving the structural integrity of the fiber. The nanostructured coating improves the interfacial shear strength by up to 83.2%, along with a 35.3% improvement in short beam shear strength. These improvements can be attributed to the enhanced chemical and mechanical interactions between the fiber and the matrix. The following findings highlight the potential for the utilization of a PDDA coating to enhance the adhesion of ANFs on fiberglass and enable the fabrication of composite structures with higher strength and toughness through a rapid, simple and effective surface treatment.