Fluorinated polyurethane coatings with adaptable surface properties

Polyurethane coatings with different network compositions were prepared in well-defined model systems as well as commercially-available formulations. The properties, such as glass-transition temperature, hardness and surface free energy, of the model network were tuned by the choice of the ingredients. All coatings were studied with respect to their bulk properties as well as their surface properties. It was found that by the addition of a fluorinated additive, the surface free energy of the coating was lowered by approximately 15mNm−1, leaving the bulk properties intact. It was also shown that these polyurethane coatings are able to adapt their surface free energy in a reversible manner when exposed to water. The magnitude and rate of surface rearrangement is strongly dependent on the network density of the coating. The effect of coating properties on the formation of a biofilm and subsequent adhesion of diatoms was studied on a selection of the coatings used in this study, and the results obtained are discussed.