A differential scanning calorimetric study of the thermotropic phase behavior of surfactant assemblies in water

Shoji Kaneshina, Michio Yamanaka

研究成果: Contribution to journalArticle査読

14 被引用数 (Scopus)

抄録

Differential scanning calorimetry (DSC) has been used to study the phase behavior of aqueous solutions of a homologous series of cationic surfactants, tetradecyl-, hexadecyl-, and octadecyltrimethylammonium bromide. Three separate endothermic transitions were observed by the heating scans of DSC. They are in turn from the higher temperature the transitions (i) from the coagel phase (or the so-called hydrated solid) to the micellar solution; (ii) from the metastable coagel, which is one of the polymorphic forms of the hydrated solid, to the supercooled micelle; and (iii) from the gel phase (metastable) to the supercooled micelle. The metastable gel phase appears when the micellar solution is supercooled and is allowed to stand for a short time at 5°C. A sufficiently long storage time (1-6 days) at 5°C is necessary to complete the transformation to the stable coagel phase. After storage at -20°C the metastable coagel phase appears. The enthalpy and entropy changes were determined for individual transitions. The difference in the enthalpy changes between first and second transitions is attributable to the difference in the dissolution enthalpy from the stable or metastable coagel to the singly dispersed surfactant solution.

本文言語英語
ページ(範囲)493-497
ページ数5
ジャーナルJournal of Colloid And Interface Science
131
2
DOI
出版ステータス出版済み - 9 1989

All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • 生体材料
  • 表面、皮膜および薄膜
  • コロイド化学および表面化学

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