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Heat‐Induced Phase Transitions from an Aqueous Solution to Precipitates in a Poly(sodium 4‐styrenesulfonate)/Tetradecyltrimethylammonium Bromide System
Author(s) -
Li Yi,
Wang Dujin,
Hao Zhengping,
Hao Jingcheng,
Han Charles C.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601861
Subject(s) - vesicle , aqueous solution , micelle , pulmonary surfactant , phase transition , phase (matter) , chemical engineering , turbidity , amphiphile , transmission electron microscopy , chemical physics , materials science , polyelectrolyte , bromide , chemistry , inorganic chemistry , thermodynamics , nanotechnology , organic chemistry , copolymer , polymer , membrane , biochemistry , physics , oceanography , engineering , geology
Abstract For the first time, temperature‐induced phase transitions upon heating and cooling an aqueous solution that contained oppositely charged polyelectrolyte and surfactant mixtures was observed. The phase transition from micelles to vesicles, then to the coexistence of vesicles and superstructures that have the morphology of melon seeds, and finally to precipitates was determined by means of turbidity measurements and transmission electron microscopy images. These phase transitions were shown to be reversible and reproducible after several heating and cooling cycles were performed on the same sample. The novel observations for the temperature‐induced phase transition from primary aggregates, such as micelles, to superstructures (i.e., vesicles) should provide new understanding for surfactant sciences, and in particular for self‐assembled amphiphilic systems.