POLYMER SURFACTANT FILMS AT THE AIR-WATER-INTERFACE .2. A NEUTRON REFLECTIVITY STUDY
Mixed polymer-surfactant films at the air-water interface have been studied using neutron reflectivity. When poly(dimethylsiloxane) is spread on the surface of a surfactant layer, the resultant mixed film is a superposition of two layers: one surfactant-rich and one polymer-rich. The composition and...
| Main Authors: | , , , , , |
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| Format: | Journal article |
| Published: |
1993
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| Summary: | Mixed polymer-surfactant films at the air-water interface have been studied using neutron reflectivity. When poly(dimethylsiloxane) is spread on the surface of a surfactant layer, the resultant mixed film is a superposition of two layers: one surfactant-rich and one polymer-rich. The composition and the degree of mixing of the layers depend on the nature of the surfactant. We find significant penetration of the polymer into a monolayer of single-chain nonionic surfactant, C 10E 5. For a double-chain anionic surfactant, AOT, no interpenetration of the two layers is detected. This difference is most probably due to the greater flexibility of the C 10E 5 monolayer compared to that of AOT. The higher degree of hydration of the nonionic surfactant layer could also play a role in the mixing behavior of the polymer and surfactant layers. The molecular thickness of the polymer layer indicates a flat two-dimensional conformation of the spread polymer. The results from this study together with those in part 1 our paper suggest that the wetting behavior of the polymer is related to the degree of interpenetration of the polymer and surfactant layers. © 1993 American Chemical Society. |
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