Abstract
Dynamic contact angles were measured by means of the Wilhelmy technique for a single fiber of 6-nylon and a plate of Teflon. The measuring liquids were n-alkanes and various polar liquids including doubly distilled water. The contact angle increased with increasing rate of advance of the three-phase line up to the rate of 0.2 mm/min and was independent of the rate in the region of 0.2-0.4 mm/min. At the rate near 0.5 mmimin the contact angle recommenced increasing. The plateau was observed at the air/water and n-alkane/water interfaces. As the thermodynamically significant contact angles the advancing and receding contact angles at the plateau were used for the estimation of the surface free energy of the solids. The dispersion component (23.8 erg/cm2) of the surface free energy of 6-nylon was estimated from the advancing contact angle and the polar component (25.5 erg/cm2) from the receding contact angle.
