Wettability of a single carbon fiber

Contact angle measurement, is a suitable method to characterize the wettability of a polymer matrix and reinforcing fibers, but it is highly challenging to measure the capillary force exerted by a probe liquid on a fiber accurately for very fine fibers like single carbon fibers. Therefore, we propose an innovative method for measuring dynamic contact angles with a tensiometer, considering both the intrinsic variability of the carbon fiber diameter and the extremely small amplitude of the capillary forces, allowing the measurement of reliable dynamic contact angles over a large range of contact line velocities. The analysis of the contact angle dynamics by the molecular-kinetic theory permits to check the relevancy of the measured contact angles and to obtain the static contact angle value, improving the prospect of employing tensiometry to better understand the wetting behavior of carbon fibers.