Synthesis of new fluorinated allyl ethers for the surface modification of thiol-ene ultraviolet-curable formulations

Thiol-ene photocurable systems based on a trifunctional thiol [trimethylolpropane tris-(3-mercaptopropanoate)] and two different multifunctional allyl ethers (trimethylolpropane triallyl ether and Boltorn U2, an allyl functional dendritic polyester) were examined. To these systems, small amounts (<1 wt%) of fluorinated allyl ethers were added for the modification of their surface properties. Two new fluorinated allyl ethers, 1H,1H-perfluoro-1-heptylallyl ether and 1H,1H-perfluoro-1-decylallyl ether, were synthesized for this purpose by allylation of the corresponding 1H,1H-perfluoro alcohols. The fluorinated monomers, despite their very low concentrations, caused sharp changes in the surface properties of the films and in the solvent resistance without any changes in the curing conditions and bulk properties. Completely hydrophobic surfaces were obtained (as a result of the selective enrichment of the fluorinated monomers on the film surfaces) that depended on the monomer structure and its concentration.