Effect of Morphology of ZnO Nanowire Arrays on Interfacial Shear Strength in Carbon Fiber Composites

ZnO nanowire arrays are grown on carbon fiber to enhance the interface strength of a polymer matrix composite without degrading the base fiber and in-plane strength of the composite. The morphology of the nanowire array is controlled during growth to create nanowires with different aspect ratios to elucidate the structure-property relations of the interphase. Nanowires are shown to double the composite interfacial shear strength at an intermediate nanowire length, indicating that an optimal point exists and the interface can be engineered to maximize the interfacial enhancement. Furthermore, the observed effect of the morphology on interface strength indicates that the bond between the ZnO nanowire array and the carbon fiber is quite strong, more than twice as strong as the interaction between the matrix and control fiber.