Biodetergent. IV. Monolayers of corynomycolic acids at the air-water interface

• Published in: Colloid and polymer science 1999-04, Vol.277 (4), p.334-339
• Main Authors: FUJII, T, YUASA, R, KAWASE, T
• Format: Article
• Language: English
• Subjects: Atomic properties; Carbon; Chains; Chains (polymeric); Chemistry; Condensing; Exact sciences and technology; Extrapolation; Fatty acids; Gas-liquid interface and liquid-liquid interface; General and physical chemistry; Monolayers; Surface physical chemistry
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s003960050389

The effects of alkyl chain length and of differences in the length of the two alkyl chains on the formation of a monolayer of chemically synthesized corynomycolic acid (2-alkyl-3-hydroxy fatty acid) at the air-water interface were examined. Hydrophobic interactions between the two alkyl chains are required for the formation of a condensed film, which is most stable when the total number of carbon atoms in the two alkyl chains is 25 or more and the difference in their lengths is one. Syn-isomers form condensed films but usually not anti-isomers. However, films may also be formed by the anti-isomer when the alkyl chain at the carboxy group (the 2-position) is longer than the alkyl chain at the hydroxy group (the 3-position). That is, the contribution of anti-isomers to condensed film formation depends on the polar carboxy group which has greater involvement in this formation. The extrapolated area for the condensed film of corynomycolic acid was 40 Å^sup 2^ per molecule, thus confirming that both the carboxy and hydroxy groups are present on the water surface when a bipolar monolayer is formed.[PUBLICATION ABSTRACT]