Measurements of Static and Low Rate Dynamic Contact Angles by Means of an Automated Capillary Rise Technique

Six solid surfaces were compared with respect to their surface quality, by measuring advancing contact angles along the solid surfaces (in the vertical and horizontal directions) at constant immersion rate. It was found that surfaces of mica, dip coated in FC-721, Teflon (FEP) heat pressed against mica, and siliconized glass yield essentially constant advancing contact angles at different locations of the solid surfaces and, thus, are well suited to dynamic contact angle measurements. Static and low rate dynamic contact angles of a number of pure liquids were therefore measured on these solid surfaces. Low rate dynamic contact angles were found to be identical with the static contact angles and independent of the velocity of the three-phase contact line (up to 0.5 mm/min).