Capillary Wave Studies of Polystyrene-b-poly(methacrylic acid) Diblock Copolymer Films at the Air−Water Interface
| Autor: | K.A. Shaffer, J. V. Gandhi, T. M. Chapman, J. V. Maher |
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| Rok vydání: | 1997 |
| Předmět: |
Poly(methacrylic acid)
Capillary wave Materials science Capillary action Surfaces and Interfaces Condensed Matter Physics Surface pressure chemistry.chemical_compound Chemical engineering Methacrylic acid chemistry Monolayer Polymer chemistry Electrochemistry Copolymer General Materials Science Polystyrene Spectroscopy |
| Zdroj: | Langmuir. 13:1592-1601 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la9608324 |
| Popis: | We have used mechanically generated capillary wave and ellipsometric techniques to investigate interfacial viscoelastic properties of adsorbed monolayers of polystyrene-b-poly(methacrylic acid) diblock copolymer at an air-water interface, as a function of both the overall molecular weight, M{sub w}, and the nominal interfacial number density of the copolymer. This experiment is a follow-up of our earlier experiment, in which we studied adsorbed monolayers of the same diblock copolymer at the toluene-water interface. Now we have changed the environment of the polystyrene block from toluene to air and have studied the effect of such a change. The most prominent effect of this change is that it is more difficult to attain equilibrium at the air-water interface. Unlike the toluene-water case, no clear saturation of surface pressure is observed at the air-water interface. The maximum surface pressure values measured at the air-water interface are smaller than the saturation surface pressure values in the toluene-water case for all the three molecular weights we have investigated. Ellipsometric study shows that only a very small fraction of the copolymer molecules added to the system is adsorbed at the air-water interface. However, substantial changes in the longitudinal elasticity and logitudinal viscosity are observed. 36 refs., 13 figs.,more » 5 tabs.« less |
| Databáze: | OpenAIRE |
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