Regensburg 2007 – scientific programme

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SYPE: Symposium Polyelectrolytes

SYPE 1: Polyelectrolytes Poster

SYPE 1.8: Poster

Wednesday, March 28, 2007, 16:00–18:30, Poster B

Deposition and nanostructure of poly(ethyleneimine)/poly(acrylic acid) multilayers in dependence of polyelectrolyte concentration — •Martin Müller, Bernd Keßler, and Wuye Ouyang — Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden

Polyelectrolyte (PEL) multilayers (PEM) of poly(ethyleneimine)/poly(acrylic acid) (PEI/PAC) were reproducibly deposited in an automated flow cell and studied in dependence of the adsorption step z and PEL concentration cPEL by in-situ ATR-FTIR spectroscopy and AFM. Quantitative information on the deposited amount and PEL composition was provided based on the integrated areas of characteristic IR bands of either PEI or PAC. Varying cPEL between 0.001 M and 0.1 M resulted in a maximum PEM deposited amount for moderate cPEL. Evidence for the release of outermost located PEI upon PAC immersion (even step) and of outermost PAC upon PEI immersion (odd step) was obtained. AFM images on the surface deposits for PEM-10 revealed smaller structural features for low and high cPEL and larger ones for moderate cPEL. The found cPEL dependent deposition and morphological features are suggested to be determined by a competition of two types of electrostatic attraction: between the outermost PEL and the underlying PEM zone (PEM formation and stability) (i) and between the outermost PEL and the immersed one (PEM rupture and solution complexation) (ii) mediated by Debye length and PEL supply. Applications are related to both charged and nanostructured surfaces for selective drug or protein interaction.