Polymer composites and laminate materials are described herein. The composites and laminate materials include a fiber component, a polymer matrix component and a quantity of carbon nanotubes coating at least a portion of the fiber component. The fiber component can be a plurality of carbon fibers. The carbon nanotubes coating the fiber component strengthen a fiber-matrix interface between the fiber component and the polymer matrix component. Methods for improving the fatigue durability of a fiber-reinforced polymer composite are also disclosed.