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Phase separation mechanism during membrane formation by dry‐cast process
Author(s) -
Matsuyama Hideto,
Nishiguchi Manabu,
Kitamura Yoshiro
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(20000725)77:4<776::aid-app9>3.0.co;2-q
Subject(s) - spinodal decomposition , nucleation , membrane , phase diagram , phase (matter) , binodal , materials science , diffusion , chemical engineering , small angle x ray scattering , chemistry , polymer chemistry , analytical chemistry (journal) , chromatography , scattering , thermodynamics , organic chemistry , optics , biochemistry , physics , engineering
Phase separation mechanisms during the membrane formation by dry‐cast process were investigated by light scattering in the cellulose acetate/dimethylformamide (DMF)/2‐methyl‐2,4‐pentanediol system. Phase separation occurred by spinodal decomposition (SD) when paths of the composition changes due to the evaporation of DMF were close to the critical point in the phase diagram. Characteristic properties of the early stage of SD such as an apparent diffusion coefficient and an interface periodic distance were obtained from the Cahn theory. Phase separation occurred by nucleation and growth (NG) when paths of the composition changes were far from the critical point. SEM observation confirmed that the membrane formed by the SD mechanism had interconnected structure, whereas that by the NG mechanism had the closed cell porous structure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 776–782, 2000