Photochemically modified thin‐film composite membranes. I. Acid and ester membranes

Abstract A photochemically active membrane was made by the interfacial copolymerization of 3‐diazo‐4‐oxo‐3,4‐dihydro‐1,6‐naphthalene disulfonylchloride and naphthalene‐1,3,6‐trisulfonylchloride with 1,6‐hexanediamine. The chemical functionality of the membrane surface was modified on irradiation of the surface of the membrane in the presence of various nucleophiles. Surface analysis techniques of attenuated total reflectance‐Fourier transform infrared and scanning electron microscopy have been used to monitor the changes in the chemistry of the thin‐film composite membranes. The surface functionality of the membrane was shown to affect the reverse osmosis flux and separation of various solutes. Results for membranes which have been converted to acid, and ester forms are presented. © 1993 John Wiley & Sons, Inc.