AbstractDynamic fiber wettability measurements are performed on T‐300 carbon and Teflon fibers immersed in hexa methyl disiloxane (HMDS) silicone oil and a difunctional liquid epoxy resin, neopentyl diglycidyl ether (NPDGE). Specifically, four types of these carbon fibers, which are used to reinforce high performance composites, are studied. Decreases in the wetting force are observed for progressive immersions of all carbon fibers in the silicone oil but not observed with Teflon fibers, indicating adsorption may be occurring on the carbon surface. Perimeters determined from these wetting measurements on carbon fibers are larger than those calculated, assuming the fibers to be smooth cylinders. Scanning electron micrographs suggest this difference is attributable to surface crenulations. All carbon fibers immersed in the epoxy resin show non‐zero contact ang