Investigation of the Pore Structure and Morphology of Cellulose Acetate Membranes Using Small-Angle Neutron Scattering. 1. Cellulose Acetate Active Layer Membranes

• Published in: Macromolecules Vol. 27; no. 23; pp. 6777 - 6784
• Main Authors: Kulkarni, Sandeep, Krause, Sonja, Wignall, G. D, Hammouda, B
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.11.1994
• Subjects: 400105 > Separation Procedures; ACETATES; ALCOHOLS; CARBOXYLIC ACID SALTS; CELLULOSE ESTERS; DIFFUSION; ESTERS; HEAVY WATER; HYDROGEN COMPOUNDS; HYDROXY COMPOUNDS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LABELLED COMPOUNDS; MATERIALS SCIENCE; MEMBRANES; METHANOL; MICROSTRUCTURE; ORGANIC COMPOUNDS; OSMOSIS; OXYGEN COMPOUNDS; PORE STRUCTURE; SCATTERING; SEPARATION EQUIPMENT; SMALL ANGLE SCATTERING; WATER 360602 > Other Materials > Structure & Phase Studies
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma00101a016

The structure of ultrathin cellulose acetate membranes, known as active layer membranes, has been investigated using small-angle neutron scattering. These membranes are known to have structural and functional similarity to the surface or 'skin' layer in commercial reverse-osmosis (RO) membranes and hence are useful model systems for understanding the structure of the RO membrane skin layer. Active layer membranes were studied after swelling them with either D sub(2)O or CD sub(3)OD. The results in both cases clearly indicated the presence of very small (10-20 angstrom) porous structures in the membrane. The presence of such pores has been a subject of long-standing controversy in this area. The data was analyzed using a modified Debye-Bueche analysis and the resultant membrane structure was seen to agree well with structural information from electron microscopic studies. Finally, a possible explanation for the differences in scattering observed between the D sub(2)O swollen membranes and the CD sub(3)OD swollen membranes has been presented.