SELECTIVE PROTEIN-TRANSPORT THROUGH A THIN CELLULOSE COATED POROUS MEMBRANE

A new composite membrane was designed and studied for permselectivity of various molecular weight proteins. The membrane is composed of a po rous substrate membrane [Durapore; poly(vinylidene fluoride)] coated w ith a thin dense layer of regenerated cellulose. This composite membra ne was fabricated by spin coating a cellulose acetate solution onto th e membrane, followed by alkaline hydrolysis of the cellulose acetate c oating to regenerate cellulose. The coated layer was physically charac terized by scanning electron microscopy (SEM) and infrared (IR) spectr oscopy. In addition, the water uptake into and permeation properties o f macromolecules across the coated and uncoated membranes were studied . A typical composite membrane coating was 0.8 +/- 0.2 mum thick, resu lting in a molecular weight cutoff of approximately 40,000 daltons. Th is composite membrane also demonstrated negligible diffusional lag tim e for permeants, due to the thin diffusional barrier. (C) 1994 John Wi ley & Sons, Inc.