Gelation-Induced Phase Separation of Poly(vinyl alcohol) in Mixed Solvents of Dimethyl Sulfoxide and Water

Time-resolved light-scattering measurements have been performed on poly(vinyl alcohol) (PVA) in mixed solvents of dimethyl sulfoxide (DMSO) and water with various mixing ratios after quenching from 100 to 25 °C to examine the physical gelation process. A broad scattering peak characteristic of phase...

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Bibliographic Details
Published in:Macromolecules 2007-11, Vol.40 (24), p.8750-8755
Main Authors: Takahashi, Nobuaki, Kanaya, Toshiji, Nishida, Koji, Kaji, Keisuke
Format: Article
Language:English
Subjects:
Applied sciences
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Properties and characterization
Solution and gel properties
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Summary:Time-resolved light-scattering measurements have been performed on poly(vinyl alcohol) (PVA) in mixed solvents of dimethyl sulfoxide (DMSO) and water with various mixing ratios after quenching from 100 to 25 °C to examine the physical gelation process. A broad scattering peak characteristic of phase separation appeared in the light-scattering profiles after a certain incubation time (t m) and the peak position (Q m) moved to higher Q with annealing time. The results contradict the theoretical predictions and experimental observations for usual phase separation systems, suggesting the effects of gelation (or network formation) on the phase separation. The growth kinetics significantly depend on the mixing ratio of DMSO and water, showing that the solvent quality is also a factor to affect the phase separation kinetics during the physical gelation process. The unusual phase separation kinetics is discussed in terms of gelation-induced phase separation.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma071256t