EFFECTS OF FABRICATION CONDITIONS ON THE STRUCTURE AND FUNCTION OF MEMBRANES FORMED FROM POLY (ACRYLONITRILE-VINYLCHLORIDE)

Phase-inversion membranes formed from poly(acrylonitril-co-vinylchlori de) (PAN-PVC) have been utilized for encapsulating living cells for tr ansplantation; however a detailed analysis of the structure and functi on of the integral skin layer has not been reported. PAN-PVC membranes fabricated under different precipitation conditions were analyzed usi ng microscopic techniques and several functional tests. Structural ana lysis with scanning atomic force microscopy (AFM) revealed the presenc e of nodular elements in the skin layer which changed as a function of precipitation conditions. In addition, membrane hydraulic permeabilit ies, sieving coefficients, and diffusive permeabilities also Varied wi th precipitation conditions. Furthermore, changes in the functional pr operties could be related to the size of the nodular elements and thei r accompanying interstitial space. The results provide insight into th e fundamental interrelationships that exist between membrane fabricati on, the fine surface morphology of the skin layer, and membrane perfor mance. (C) 1998 Elsevier Science B.V. All rights reserved.