Effect of Zinc Oxide Nanowire Length on Interfacial Strength of Carbon Fiber Composites

Vertically aligned arrays of zinc oxide nanowires can serve as an adjustable interface for fiber composites through controllable synthesis techniques. When grown on carbon fiber surfaces as a fiber-matrix interphase of a composite, ZnO nanowires increase the surface area of interaction between fiber and matrix, and thus cause a greater interfacial shear strength of the composite. The ability to control the interfacial strength of this interphase through tailored morphologies enables the design of composite systems to specific applications. This report focuses on the controlled growth of ZnO nanowires and correlates the relationship between nanowire length and interfacial shear strength of the composite. Previous studies have focused on the effects of nanowire morphology on the interfacial strength; however, the data was limited to nanowire lengths < 1μm due to problems with nanowire uniformity and cleanliness [1]. Here, a new synthesis method is applied to the growth of zinc oxide nanowires on carbon fiber that enables the production of long, vertically aligned, uniform nanowires while maintaining the tensile properties of the fiber. The nanowires created by the new method are then compared to previous method nanowires by scanning electron microscopy imaging. Lastly, the interfacial shear strength of the fiber/polymer matrix composite is tested using single fiber fragmentation and correlated to the nanowire length of each method.