Phase diagram and phase structure of the sodium di-n-pentyl phosphate-water system.1H pulsed-gradient NMR self-diffusion,31P NMR and x-ray diffraction studies

H. Hirata, S. Aoki, K. Taga, H. Okabayashi, T. Yoshida, T. Kawakatsu

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Sodium di-n-pentylphos phate (DPP) has been synthesized, and the phase diagram of the DPP-water system consisting of five regions (I, II, III, IV, and V) has been determined. The phase structure has been investigated by1H pulsed-gradient NMR self-diffusion,31P NMR and x-ray low angle diffraction methods. The results are summarized as follows. In region I, there exist two critical micelle concentrations (CMC), indicating that this region is in a monomer-micelle equilibrium and that variation in the aggregated state occurs at the second CMC. Region II is a two phase area in which regions I and IV coexist. In region III, hydrated crystals and an aqueous solution of DPP coexist. Region IV is a homogenous, transparent and fluid phase and the results of31P NMR spectra and x-ray diffraction patterns reveal the formation of a highly organized structure, similar to a lamellar-like structure. Region V is a homogenous, transparent and fluid phase and the self-diffusion coefficient value and31P NMR spectra show that its phase structure is very similar to that for the concentrated sample in region I.

Original languageEnglish
Pages (from-to)1080-1087
Number of pages8
JournalColloid & Polymer Science
Volume273
Issue number11
DOIs
Publication statusPublished - 1995 Nov 1
Externally publishedYes

Keywords

  • Sodium di-n-pentyl phosphate
  • phase diagram
  • phase structure

ASJC Scopus subject areas

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

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