[en] This paper reports on the pH-dependent adsorption of weak the polyelectrolytic diblock copolymer poly(2-vinylpyridine)-block-poly(dimethylaminoethyl methacrylate), (PVP-b-PDMAEMA). Aqueous PVP-b-PDMAEMA solutions have been adsorbed on alkaline pretreated silicon substrates. Altogether two copolymers differing in block ratio and molecular weight were used for the investigations. While the electrical charge of both samples in solution was investigated by electrophoretic measurements, the adsorbed polymer layers were studied with ellipsometry and atomic force microscopy (AFM). Depending on pH the electrical charge of both blocks of the diblock copolymer varied. Three different regimes have been identified. Under acidic conditions at pH < 5, both blocks are mainly positively charged. At medium pH between 5 and 8, only the PDMAEMA block is positively charged. At pH > 8, both blocks are nearly uncharged and a polymer precipitation occurred in solution. Each of these pH regimes was characterized by a specific adsorption behaviour leading to two adsorption maxima at acidic and alkaline pH values, while at medium pH a plateau in the adsorbed amount was observed. Moreover, the structures of the polyelectrolytes formed on the substrate after adsorption were specific to each of the three pH regimes.
Research Center/Unit :
Center for Education and Research on Macromolecules (CERM)
Disciplines :
Chemistry Materials science & engineering
Author, co-author :
Mahltig, Boris; Institut für Polymerforschung, Dresden, Germany
Gohy, Jean-François; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Antoun, Sayed; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Jérôme, Robert ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Stamm, Manfred; Institut für Polymerforschung, Dresden, Germany
Language :
English
Title :
Adsorption and structure formation of the weak polyelectrolytic diblock copolymer, PVP-b-PDMAEMA
The DFG-Schwerpunkt ‘‘Polyelektrolyte (grant Sta 324/5–2) BELSPO - SPP Politique scientifique - Service Public Fédéral de Programmation Politique scientifique ESF - European Science Foundation
Commentary :
The original publication is available at http://www.springerlink.com/content/793mfhxf97gyykv7/fulltext.pdf. The authors acknowledge Colloid and Polymer Science (Springer) for allowing them to archive this paper.