Ordering of Poly(ethylene oxide)/Poly(propylene oxide) Triblock Copolymers in Condensed Films
| Autor: | Stevin H. Gehrke, Gregory S. Retzinger, Stephen M. O'Connor |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Materials science
Ethylene Ethylene oxide technology industry and agriculture Oxide Ether macromolecular substances Surfaces and Interfaces Condensed Matter Physics chemistry.chemical_compound Adsorption chemistry Monolayer Polymer chemistry Electrochemistry Copolymer General Materials Science Propylene oxide Spectroscopy |
| Zdroj: | Langmuir. 15:2580-2585 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la9811113 |
| Popis: | Triblock copolymers of the form PEOαPPOβPEOα [where PEO is poly(ethylene oxide) and PPO is poly(propylene oxide)] form stable insoluble monolayers at both the air−water and solid−water interfaces. At the air−water interface, the nominal equilibrium spreading area of copolymers that have the same PPO content, or “core”, increases with increasing PEO content by an amount equivalent to the area of the hydrated ethylene ether subunits. With compression, a PEO-dependent transition from an expanded to a more condensed monolayer occurs at ∼10 dyn·cm-1, presumably because of condensation of PEO segments onto the core and out of the plane of the surface. Consistent with these results and interpretation, the thickness of adsorbed films of copolymers from series that have fixed cores increases approximately linearly with ethylene oxide content. At collapse of copolymer films, the nominal area per moleculeregardless of the number of ether functions in the PEO segmentis that of the hydrated PPO core. On the basis of t... |
| Databáze: | OpenAIRE |
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