Determination of surface wettability of polymeric hollow fibres

Abstract

Surface wettability significantly affects the condensation and therefore the heat transfer when condensation occurs. The materials are classified as either hydrophobic or hydrophilic. Materials with a lower contact angle are more suitable for heat transfer applications associated with condensation. The dynamic contact angle is one way to define surface wettability. In this contribution, the Wilhelmy method was used for measuring the force of the interaction of a fibre at the liquid–gas interface. The method is based on immersing a sample in a liquid and then removing it. This study compares the influence of the type of polymeric material and surface finishes of hollow fibres on the dynamic contact angle. Polypropylene fibres and polypropylene fibres with a Trapylen®, (TRAMACO GmbH, Germany) surface finish achieve a larger dynamic contact angle (the advancing dynamic contact angle measured in water is around 100°). Therefore, they seem to be a better alternative than polycarbonate, polyether ether ketone and polyamide (the advancing dynamic contact angle in water is around 80°).