Short description
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This project aims to use the colloidal probe technique based on the atomic force microscope (AFM) to measure and interpret interaction forces between well-defined heterogeneously charged surfaces. These surfaces will be prepared by absorbing cationic dendrimers on negatively charged sulfate latex particles. The interaction forces will be studied systematically, particularly near the isoelectric point, as a function of the salt level and size of the heterogeneities. Thereby, the latter quantity can be systematically varied with the dendrimer generation. The results will be interpreted in terms of current theories of interaction forces between such surfaces, and one expects to establish their regimes of validity. Similar studies will be carried out with linear polyelectrolytes. Their comparison with the dendrimer results will allow ad-adressing the role of bridging in these systems. This work will further develop the colloidal probe technique as a surface analytical tool and provide understanding of interactions between polyelectrolyte-coated and hydrophobic interfaces.
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Further information
(English)
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Full name of research-institution/enterprise: Université de Genève Department of Inorganic, Analytical, and Applied Chemistry Sciences II
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Partners and International Organizations
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AT, BG, CH, CY, CZ, DE, ES, FI, FR, GR, HR, HU, IE, IL, IT, LT, LV, NL, NO, PL, PT, RO, RS, SE, SI, SK, TR, UK
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Abstract
(English)
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This project used the colloidal probe technique based on the atomic force microscope (AFM) to measure and interpret interaction forces between well-defined heterogeneously charged surfaces. These surfaces will be prepared by adsorbing cationic polyelectrolytes on negatively charged sulfate latex particles. The interaction forces have been studied systematically, particularly near the isoelectric point, as a function of the salt level and size of the heterogeneities. Thereby, the latter quantity can be systematically varied with the dendrimer generation, and one finds that attractive forces strenghten within increasing generation and decreasing salt level. On the other hand, when the charge is neutralized with linear poly(ethylene imine), the attractive forces do neither show dependence on the molecular mass nor on the salt level. We conclude that these surface layers are unusually homogeneous.
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