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Authors Dominguez-Espinosa, G. ; Synytska, A. ; Drechsler, A. ; Gutsche, C. ; Kegler, K. ; Uhlmann, P. ; Stamm, M. ; Kremer, F.
Title Optical tweezers to measure the interaction between poly(acrylic acid) brushes
Date 10.10.2008
Number 17942
Abstract Optical tweezers are employed to measure the forces of interaction within single pairs of poly(acrylic acid) (PAA) grafted colloids with an extraordinary resolution of ±0.5 pN. Parameters varied are the concentration and valency of the counterions (KCl, CaCl2) of the surrounding medium as well as its pH. The data are quantitatively described by a recently published model of Jusufi et al. [Colloid Polym Sci 2004; 282:910] for spherical polyelectrolyte brushes which takes into account the entropic effect of the counterions. For the scaling of the brush height a power law is found having an exponent of 0.25 ± 0.02 which ranges between the values expected for spherical and planar brushes. From the model the ionic concentration inside the brush is estimated in reasonable agreement with the literature.
Publisher Polymer
Wikidata
Citation Polymer 49 (2008) 4802-4807
DOI https://doi.org/10.1016/j.polymer.2008.09.007
Tags polymer brushes optical tweezers polyacrylic acid brushes spherical polyelectrolyte brushes charged polymer brushes salt-free solution diblock copolymers adsorption friction surfaces solvent forces model

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