1. Surface Shear Viscosity and Phase Transitions of Monolayers at the Air-Water Interface
- Author
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F. Ciuchi, Annalisa Relini, and Ranieri Rolandi
- Subjects
Phase transition ,Chromatography ,Physics and Astronomy (miscellaneous) ,ved/biology ,Sulfolobus solfataricus ,ved/biology.organism_classification_rank.species ,General Engineering ,Thermodynamics ,Atomic and Molecular Physics, and Optics ,Viscosity ,Oleic acid ,chemistry.chemical_compound ,Membrane ,chemistry ,Monolayer ,Polar ,Coupling (piping) - Abstract
― The canal method has been employed to measure the in-plane steady shear viscosity of monolayers of bolaform lipids extracted from the membrane of the thermophilic microorganism Sulfolobus solfataricus. Monolayers were formed with the polar lipid extract (PLE), which is a mixture of several bolaform lipids, each one endowed with two nonequivalent polar headgroups. Viscosities were obtained from the measured flows by using the equation introduced by Joly; this equation contains a semiempirical parameter A, which takes into account the monolayer-subphase mechanical coupling. Measuring the flows for two different substances (PLE and oleic acid) and channel widths, the monolayer viscosities and the parameter A were determined at the same time. The analysis of the viscosity data according to the free area model shows evidences of the molecular conformational changes matching monolayer phase transitions. more...
- Published
- 1995
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