Oscillations in solvent fraction of polyelectrolyte multilayers driven by the charge of the terminating layer
We have investigated polyelectrolyte multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) in contact with D2O by neutron reflectometry. The study particularly focuses on the changes in the solvent fraction of the system upon addition of a layer. When the layers are deposit...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 20(2004), 26 vom: 21. Dez., Seite 11465-72 |
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| Weitere Verfasser: | , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2004
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article |
| Zusammenfassung: | We have investigated polyelectrolyte multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) in contact with D2O by neutron reflectometry. The study particularly focuses on the changes in the solvent fraction of the system upon addition of a layer. When the layers are deposited at a low salt concentration (0.25 M NaCl), no significant changes in the solvent fraction are detected. In contrast, at a larger salt concentration (1 M NaCl), oscillations in the solvent fraction are detected when a new layer is deposited. In this case, addition of PSS systematically increases the solvent volume fraction, and addition of PAH decreases the solvent fraction. The results suggest that one of the parameters driving the oscillations in solvent fraction is the uncompensated charges present in the layers. This study opens new perspectives on results previously published by other authors: in addition to polymer desorption, water uptake or release might contribute to the different regimes of multilayer growth reported in the literature (linear, asymmetric, or exponential growth). In addition, comparison to NMR results previously reported allows for conclusions about the mobility of the solvent in the multilayers: the average rotational correlation time of the water molecules in the polyelectrolyte layers decreases upon addition of PSS and increases upon addition of PAH |
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| Beschreibung: | Date Completed 03.02.2006 Date Revised 14.12.2004 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 1520-5827 |