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

Shoji Kaneshina, Michio Yamanaka

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)493-497
Number of pages5
JournalJournal of Colloid And Interface Science
Volume131
Issue number2
DOIs
Publication statusPublished - Jan 1 1989

Fingerprint

Phase behavior
Surface-Active Agents
assemblies
Surface active agents
surfactants
Scanning
Enthalpy
scanning
Metastable phases
Water
enthalpy
Micelles
water
Differential scanning calorimetry
micelles
heat measurement
Gels
gels
Cationic surfactants
bromides

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

Cite this

A differential scanning calorimetric study of the thermotropic phase behavior of surfactant assemblies in water. / Kaneshina, Shoji; Yamanaka, Michio.

In: Journal of Colloid And Interface Science, Vol. 131, No. 2, 01.01.1989, p. 493-497.

Research output: Contribution to journalArticle

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