PHOTOCHEMICALLY MODIFIED THIN-FILM COMPOSITE MEMBRANES .2. BROMOETHYLESTER, DIOXOLAN, AND HYDROXYETHYL ESTER MEMBRANES

A photochemically active thin-film composite membrane was made by the interfacial copolymerization of a mixture of 3-diazo-4-oxo-3,4-dihydro -1,6-naphthalene disulfonylchloride and naphthalene-1,3,6-trisulfonylc hloride in CCl4 with aqueous 1,6-hexanediamine on the surface of a pol ysulfone ultrafiltration membrane. The chemical functionality of the r esulting polysulfonamide membrane surface was modified via a photochem ical reaction in the presence of various nucleophiles to form membrane s containing bromoethyl ester, dioxolan, and hydroxyethyl ester functi onality. Surface analysis techniques of attenuated total reflectance-F TIR, scanning electron microscopy (SEM), energy disperse spectral anal yzer (SEM/EDS), and electron spectroscopy (ESCA) were used to confirm the changes in the chemistry of the thin-film composite membranes. Cha nges in chemistry, on irradiation, were also examined with model compo unds. The reverse osmosis flux and separation of various solutes with these membranes are reported and discussed in terms of the photochemic al modifications of the membrane surface. (C) 1994 John Wiley & Sons, Inc.