Studies of surface modification of polymers via photo-initiated grafting

Industrial biosynthesis of proteins used in medical therapy involves filtration through polymeric membranes in order to separate them from fermentation mixtures. At present, the overall yields of such processes are low and consequently the products are very expensive. This is chiefly because the membranes foul by settlement of proteins on them which eventually bind and plug the pores. The membranes in question are at present made from materials which have hydrophobic surfaces. It was believed that a neutral, water-binding surface would reduce or eliminate fouling. In order to create such a surface, a vapour-phase, photoinitiated grafting process, developed by Ranby(^28),was used to graft poly(HEMA) onto the surface of Ultem films and membranes. The grafted surfaces were characterised by contact angle measurements with water and ESCA, and tested for fouling propensity. It was shown that this technique is suitable for grafting poly(HEMA) onto Ultem films and membranes, and that the graft results in a significant reduction in the protein fouling propensity.