ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Based on Maxwell displacement current (MDC) and surface pressure measurements by monolayer compression, the physicochemical properties of chiral and racemic phospholipid [α-phosphatidylcholine dipalmitoyl (DPPC)] monolayers at the air–water interface were investigated. It was found that at a temperature of 20 °C, the chiral and racemic phospholipid monolayers exhibited similar pressure-area isotherms with a pressure plateau between 65 and 85 Å2, usually attributed to the two-dimensional (2D) phase transition from expanded monolayer to condensed one. Nevertheless, with MDC measurement some critical peaks in the 2D pressure plateau region with different amplitude and sign were detected related to the chirality of the phospholipid samples. This result clearly demonstrates that microscopic chirality affects the electrical properties of monolayers. To investigate the chiral effect theoretically, a twist-conformation molecular model was raised by a modification of the simple rodlike model and biaxial rodlike model, which were developed in our previous work. The analysis based on this modified model reveals that the monolayer properties, especially the MDC behavior by compression, are profoundly influenced by the chirality of molecules. © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.479150
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