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Title Complex pH- and temperature-sensitive swelling behavior of mixed polymer brushes
Date 29.06.2010
Number 21425
Abstract The ability of a mixed polymer brush consisting of poly(N-isopropyl acrylamide) (PNIPAAM) and poly(acrylic acid) (PAA) to modify physicochemical interfacial properties is presented. The answer of the binary brush toward changes of environmental conditions like temperature, salt concentration, and pH value was investigated by in situ spectroscopic VIS-ellipsometry as well as AFM and contact angle mesurements in the dry state and compared with the behavior of the corresponding homopolymer brushes. A coupled swelling of PNIPAAm and PAA could be found, leading to a complex pH-, salt-, and temperature-sensitive swelling behavior of these mixed brushes, also depending on the composition of the brush. The complex interaction of the two polymers resulted in new properties of the mixed system. Although the temperature sensitivity of the mixed system was decreased compared with that of the corresponding PNIPAAM brushes, the sensitivity toward pH and salt concentration was amplified compared with that of pure PAA brushes. Additionally it is shown that in spite of the decreased temperature sensitivity of the mixed brush, a temperature-dependent adsorption of human serum albumin was observed whereas an increased adsorption affinity was found that is not predictable from the adsorption affinity of the corresponding homopolymer brushes. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1606-1615, 2010
Publisher Journal of Polymer Science: Part B: Polymer Physics
Identifier
Citation Journal of Polymer Science: Part B: Polymer Physics 48 (2010) 1606-1615
DOI http://dx.doi.org/10.1002/polb.22021
Authors Bittrich, E. ; Kuntzsch, M. ; Eichhorn, K.-J. ; Uhlmann, P.
Tags binary brushes in situ spectroscopic ellipsometry refractive index stimuli-sensitive polymers swelling poly(acrylic acid) brushes polyelectrolyte brushes grafting density protein adsorption aqueous-solutions molecular-weight surface poly(n-isopropylacryla

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