Surface functionalization with phosphazenes: part 6. Modification of polyethylene-co-polyvinylalcohol copolymer surface plates with fluorinated alcohols and azobenzene derivatives using chlorinated phosphazenes as coupling agents

In this paper we describe a two-step surface modification process of poly(ethylene-co-vinyl alcohol) by exploiting hexachlorocyclophosphazene and poly(dichlorophosphazene) as coupling agents. Part of the P–Cl groups of the chlorophosphazenes is first reacted with the surface hydroxylic groups of the substrate to form covalent P–O–C bonds, the remaining being utilized for successive substitution reactions with different nucleophiles (i.e. 2,2,2-trifluoroethanol, heptadecafluorononanol and 4-hydroxyazobenzene). Modified surface properties, such as hydrophobicity improvement with fluorinated alcohols and photochromic features with the azobenzene derivative, were verified by contact angle measurements and UV–Vis spectroscopy, respectively, while changes in surface composition were demonstrated through XPS spectroscopy.