Topography and Wettability of Waterborne Polyurethane Coatings with Varying Amounts of Hard Segments

Abstract

Topography and wettability plays an important role to fouling release performance of a coating. Surface morphology and water contact angles (WCA) depending on time of three waterborne polyurethane (WPU) coatings were studied by laser scanning microscope and optical contact angle meter. The results show that WPU coatings with low hard segment content are consisted of hard segment domains, soft segment domains and crack-like non-cohesive regions. With increasing hard segment content, nanostructured micro-phase separated topography is easier to forming, and crack-like non-cohesive regions is reduced. A stable hydrophobic surface in the WPU system can be obtained by drying coating at 60C as well as adding hard segment content to improve fouling release performance of the coatings.