文章基本信息

标题：Stability of fatty acid monolayers and the relationship between equilibrium spreading pressure, phase transformations, and polymorphic crystal forms
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作者：Richard E. Heikkila ; Chui N. Kwong ; David G. Cornwell 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1970
卷号：11
期号：3
页码：190-194
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Force-area isotherms were obtained for hexadecanoic, octadecanoic, eicosanoic, and docosanoic acid monolayers at different compression rates. Equilibrium spreading pressures were determined both by monolayer collapse and by spreading from the bulk phase. Monolayers formed metastable phases at all pressures above their equilibrium spreading pressures and at all surface areas smaller than the surface areas at their equilibrium spreading pressures. These metastable phases collapsed to stable phases at the equilibrium spreading pressures of the fatty acids. Collapse phenomena and compression experiments at very slow compression rates suggested that a previously unrecognized phase transformation occurred at the equilibrium spreading pressure. The surface area at this phase transformation corresponded to the cross-sectional area of the C-form of the fatty acid crystal. Fatty acid monolayers at the phase transformations previously described by other workers had surface areas which were closely related to molecular areas in their A and B polymorphic crystal forms. These correlations indicated that molecular structure in saturated fatty acid monolayers was similar to molecular structure in fatty acid crystals.
关键词：hexadecanoic ; octadecanoic ; eicosanoic ; docosanoic ; compression rate ; collapse ; surface area ; molecular structure