Pressure and pH dependence of the structure of a fatty acid monolayer with calcium ions in the subphase
- 15 January 1992
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 96 (2), 1556-1559
- https://doi.org/10.1063/1.462139
Abstract
We have studied the effect of pressure and pH on Langmuir monolayers of heneicosanoic acid in the presence of calcium ions in the subphase. At very low pH the monolayer is unaffected by calcium ions; as the pH is increased, the head groups are pulled closer together and the chain tilt at zero pressure decreases. As a result, the phase transitions seen along the isotherms occur at lower pressures. When the isotherms become featureless, the chains are untilted at all pressures. At very high pH, a new untilted structure is observed.Keywords
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