Surface Behavior of Spread Sodium Eicosanyl Sulfate Monolayers.: 1. π/AIsotherms Determined on a Langmuir Film Balance and on Drop Surfaces and Brewster Angle Measurements
✍ Scribed by R. Wüstneck; S. Siegel; Th. Ebisch; R. Miller
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 633 KB
- Volume
- 203
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
such layers. Chang and Rosano reported a p/A isotherm Spread sodium eicosanyl sulfate (SES) monolayers were characof sodium octadecyl sulfate (2), and Hendrikx on sodium terized by p/A isotherms and Brewster angle microscopy (BAM). docosyl sulfate (3). At considerably low surface coverages During compression three different states can be distinguished by (0.60-0.80 nm 2 /molecule) a remarkable film pressure was BAM: a dark expanded phase, a condensed phase, and bright dots. already observed. At a surface coverage of about 0.24 nm 2 /
The bright dots are interpreted as traces of eicosanol. p/A isotherms molecule the films collapsed. A phase transition point in the were determined with a conventional Langmuir film balance and p/A isotherm was found for sodium octadecyl sulfate, which with the pendant drop technique. Depending on the pH SES desorbs is more pronounced at high pH (10.9 and 5.5) 2 . For sodium from the monolayer. At a constant surface pressure the desorption docosyl sulfate no phase transitions were detected (3).
was characterized by changes in the monolayer area. At pH 3 a reduction of 20% of the monolayer area was observed on a Langmuir