Novel Growth of Multiscale Carbon Nanofilaments on Carbon and Glass Fibers

Carbon nanofilaments (CNFs) were grown on the surface of microscale carbon-fibers and glass fibers at low temperature using palladium as a catalyst to create multiscale fiber reinforcing structures with potential applications in structural composites. Employing a relatively new method, in which carbon structures are grown from fuel rich combustion mixtures on certain catalytic metals, multiscale filament structures were grown from ethylene/oxygen mixtures at 550 °C on commercial pitch carbon fibers and fiberglass. The filaments grew in different size distributions and distinct morphologies (whiskers and spirals) depending on the base fiber. Submicron fibers (ca. 200 nm) and spirals (ca. 50 nm) were dominating the grown species over the fiberglass substrate. Relatively short, densely spaced nanofilaments (ca. 10 nm), and a slightly less dense layer of larger (ca. 300 nm diameter) faster growing fibers were found to exist together to create a unique multiscale carbon structures over the pitch carbon fiber substrate. Transmission electron microscopy indicated poor crystallinity for the nanoscale carbon filaments grown on both pitch carbon fibers and fiberglass.