Spreading pressures for fatty-acid crystals at the air/water interface

Makio Iwahashi, Nobuko Maehara, Yoshihide Kaneko, Tsutomu Seimiya, Steven R. Middleton, Norman R. Pallas, Brian A. Pethica

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Published values for the spreading pressures of lipids at the air/water interface are inconsistent. As part of a collaborative programme to establish criteria for surface manometry a detailed study was made of the spreading pressures for tetradecanoic, pentadecanoic and hexadecanoic acid crystals prepared from melts and solutions. The spreading pressures vary considerably for a given acid. The removal of solvents from recrystallised acids and the solubilities of chosen crystal samples in hexane were measured. The spreading pressures were then correlated for the various crystal preparations. Optical and scanning electron microscopy were used to characterise crystal geometries, and the crystallographic forms were determined by X-ray diffraction. It was established that solvent retention in the crystals can lower the spreading pressure, and that crystals with microscopic points and edges show high spreading pressures. The results can be interpreted simply by thermodynamic arguments. Data on the effect of temperature on the spreading pressures and solubilities are also presented, and the enthalpies of spreading and solution are calculated.

Original languageEnglish (US)
Pages (from-to)973-981
Number of pages9
JournalJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
Volume81
Issue number4
DOIs
StatePublished - Dec 1 1985
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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