PENETRATION OF INSOLUBLE LIPID MONOLAYERS AT THE AIR-WATER-INTERFACE BY WATER-SOLUBLE BLOCK-COPOLYMERS AND HOMOPOLYMERS

Citation
Jr. Charron et Rd. Tilton, PENETRATION OF INSOLUBLE LIPID MONOLAYERS AT THE AIR-WATER-INTERFACE BY WATER-SOLUBLE BLOCK-COPOLYMERS AND HOMOPOLYMERS, Langmuir, 13(21), 1997, pp. 5524-5527
Citations number
23
Categorie Soggetti
Chemistry Physical
Journal title
ISSN journal
07437463
Volume
13
Issue
21
Year of publication
1997
Pages
5524 - 5527
Database
ISI
SICI code
0743-7463(1997)13:21<5524:POILMA>2.0.ZU;2-O
Abstract
We used scanning angle reflectometry to directly measure the extent of water-soluble polymer adsorption to insoluble dipalmitoylphosphatidyl choline monolayers at the air-water interface. Although high molecular weight polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock copolymers are kinetically prevented from forming adsorbed brushes on solid surf aces, they did manage to adopt a more extended or brushy conformation at the fluid interfaces examined here. For both PS-PEO and PEO homopol ymer, the ability of the adsorbing polymer to drive the Liquid expande d-to-liquid condensed monolayer phase transition facilitated monolayer penetration. The significance of this excluded area sink effect in th e monolayer penetration mechanism depended on the polymer architecture . PS-PEO was a more effective monolayer penetrator than PEO homopolyme r owing to its ability to increase the PEO block extension when penetr ating denser monolayers. Thus, both polymer architecture and excluded area effects determine the effectiveness of monolayer penetration.