[en] A weak diblock polyampholyte PMAA-b-PDMAEMA, poly(methacrylic acid)-block-poly((dimethylamino)ethyl methacrylate), was investigated as a model system for the influence of an acid-base-equilibrium of a phthalic acid buffer system on the polyelectrolyte adsorption behaviour. The adsorption of polyampholyte from aqueous solution onto silicon surfaces is known to be strongly influenced by the parameters of the polymer solution and the properties of the polyampholyte itself like block ratio or molecular weight. In the case of the investigated polyampholytes, the main parameter with the most significant influence on the adsorption is the pH. The big influence of pH on adsorption results from the charges of the polymer chains and the substrate, which are determined by the pH. Therefore, it should be useful to investigate the influence of a buffer system on the polyampholyte adsorption. On the one hand the buffer system enables to determine the pH of the aqueous polyampholyte solution more precisely. On the other hand the concentrations of different phthalic species like the phthalic acid, the hydrogen phthalate and the phthalate are strongly influenced by pH. These different species were observed to have a strong influence on the adsorption behaviour of the polyampholyte, so the adsorption as function of pH was observed to be also determined by the acid-base-equilibrium of the buffer system. The adsorbed amount of polyampholyte dried after the adsorption process was determined using ellipsometry, while the surface topography of these adsorbed layers were characterized by atomic force microscopy (AFM).
Center for Education and Research on Macromolecules (CERM)
Politique Scientifique Fédérale (Belgique) = Belgian Federal Science Policy ; The DFG-Schwerpunkt “Polyelektrolyte” (grant Sta 324/5-2)
The original publication is available at www.springerlink.com/content/n387g04532u68282/?p=9013172f394044118f537da7fe4ced8b&pi=1. The authors acknowledge Journal of Polymer Research (Kluwer Academic Press) for allowing them to archive this paper.