A small-angle neutron scattering study of the ethyl (n-octyl) phosphate micelles in water

H. Hirata, S. Katayama, H. Okabayashi, M. Furusaka, T. Kawakatsu

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Mixed-double chain anionic surfactants, barium- and lithium-salts of ethyl(n-octyl) phosphate (EOP), which are asymmetric in the molecular shape, and a series of identical chain di-n-alkyl phosphate lithium salts have been synthesized. The limiting partial molar volume of a PO4- group (23.43 ± 0.41 cm3mol-1) for use in small-angle neutron scattering analysis was determined by density measurements of a series of identical chain di-n-alkyl phosphate lithium salts. For lithium EOP-D2O system, a critical micellar concentration (2.3 wt%) was determined by 31P NMR spectra. The micellar shape and size in the EOP-water binary system has been investigated by using small-angle neutron scattering (SANS) spectra. It has been found that the micelles of barium EOP in water have the shape of a prolate spheroid and aggregation numbers (n) equal to 48 at 23° C and 52 at 50° C. For the lithium EOP-micellar system, it has been found that the minimum micelle with an aggregation number n = 21 is spherical and micellar growth and variation from the spherical to the prolate shape might occur with an increase in concentration above the CMC.

Original languageEnglish
Pages (from-to)245-252
Number of pages8
JournalColloid and Polymer Science
Volume274
Issue number3
DOIs
Publication statusPublished - 1996 Mar
Externally publishedYes

Keywords

  • Ethyl(n-octyl) phosphate
  • Micelle
  • SANS

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Colloid and Surface Chemistry
  • Materials Chemistry

Fingerprint Dive into the research topics of 'A small-angle neutron scattering study of the ethyl (n-octyl) phosphate micelles in water'. Together they form a unique fingerprint.

Cite this