[nanoPost] Self-replenishing low adherence coatings

Research Centre Netherlands

Low surface tension coatings are widely used today since their water/oil repellency makes them easily cleanable. The low surface tension is provided by fluorine or silica containing polymers/species that are present on the surface of a film. Difficult processing and price of films with a large amount of fluorine in the bulk makes them not suitable for a wide range of applications. Therefore, the self-stratification of low amount of fluorine rich species upon film formation has been of the increasing research interest as the strategy for obtaining coatings with low surface energy and desired bulk properties. The low surface tension of these films is provided by a thin fluorine-rich layer on the surface of a coating. A drawback of these materials is that the fluorine enriched layer is rather thin (~ 20 nm) and therefore will not sustain low surface tension upon damage or wearing off of the material.

Herewith self-replenishing low adherence films are defined as those able to retain low surface energy even upon damage by providing the sufficient amount of low surface energy species on newly created surfaces. The approach we have taken is to relatively homogeneously distribute fluorinated species that contain long polymer spacer throughout the bulk of a film. These species will be able to reorient or even move from sub-layers driven by the surface tension of the new film/air interface. The process will start spontaneously after the damage on sufficient temperature as the prerequisite for mobility of the chains. Once on the new interface, they will lower the surface tension of the complete film.

Miscibility, mobility and spacer length of network precursors (dangling chains that are fluorine end-capped) as well as the mobility of the bulk polymer largely influence the possibility of self-replenishing. The possibility of making self-replenishing low surface films and using force displacement measurements and XPS for characterizing the change in surface energy of a film before and after the damage will be represented.