Water repellent acrylic photopolymers containing fluorinated monomers

Fluorine polymers commonly referred to as fluoropolymers, can greatly enhance the properties of coatings used in modern industrial; house hold and construction products. The qualities of fluoropolymer resins and oligomeric additives make them an ideal solution for applications requiring a high resistance to solvents, acids and bases, high thermal stability, low friction and excellent weatherability1,2. These unique properties result from the fact that C-C bonds are strengthened by the incorporation of fluorine atoms into the organic materials. For example, high steric hindrance achieved when carbons are bonded to fluorine atoms results in the protection of the carbon backbones from high temperature or corrosive environments.

In order to benefits from the advantages of the photopolymerization process and the special properties of fluorocarbon substances, UV-cured fluoroacrylate coatings were developed. The control of the hydrophobic properties of a fluoroacrylate UV-cured is important in different industrial fields such as: fabrics (fiber protection), construction (antigraffity) and electronics (antireflection). But, the preparation of a fluoroacrylate coating with a good stability in hot water is one of the challenges encountered researchers.

It is known that the amount and more specifically the organization of fluorinated chains on the surface affect the hydrophobic properties of a fluoroacrylate coating.

In this paper, we have tried to understand how the fluorinated monomer content promotes the fluorine stability on the surface and how it affects the hydrophobicity of acrylic films before and after immersion in hot water.

The Confocal Raman Microscopy (CRM) was implemented as an indirect analysis method to study the permeability of the monomer surface toward oxygen to characterize the organization of the fluorinated chains on the surface before curing. After determination of the optimal concentration of fluoroacrylates, advancing and the receding contact angles measurements allow to characterize the surface properties of the films and to corroborate the data obtained by CRM. Then the ability of the film to resist an immersion in hot water was evaluated as well as the effect of a thermal annealing to recover some of the properties of the film lost in hot water.