Chemical analysis and aqueous solution properties of charged amphiphilic block copolymers PBA-b-PAA synthesized by MADIX©

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:316

Article

Jacquin, M. ; Muller, P. ; Talingting-Pabalan, R. ; Cottet, H. ; Berret, J. F. ; Futterer, T. ; Theodoly, O.

关键词: diblock copolymer;    micelle;    interfacial tension;    exchange kinetics;    self-assembly;    polyelectrolyte;    fractionation;   

DOI  :  10.1016/j.jcis.2007.08.025

来源: Elsevier

【 摘 要 】

We have linked the structural and dynamic properties in aqueous solution of amphiphilic charged diblock copolymers poly(butyl acrylate)b-poly(acrylic acid), PBA-b-PAA, synthesized by controlled radical polymerization, with the physico-chemical characteristics of the samples. Despite product imperfections, the samples self-assemble in melt and aqueous solutions as predicted by monodisperse microphase separation theory. However, the PBA core are abnormally large; the swelling of PBA cores is not due to AA (the Flory parameter chi(PBA/PAA), determined at 0.25, means strong segregation), but to h-PBA homopolymers (content determined by liquid chromatography at the point of exclusion and adsorption transition, LC-PEAT). Beside the dominant population of micelles detected by scattering experiments, capillary electrophoresis CE analysis permitted detection of two other populations, one of h-PAA, and the other of free PBA-b-PAA chains, that have very short PBA blocks and never self-assemble. Despite the presence of these free unimers, the self-assembly in solution was found out of equilibrium: the aggregation state is history dependant and no unimer exchange between micelles occurs over months (time-evolution SANS). The high PBA/water interfacial tension, measured at 20 mN/m, prohibits unimer exchange between micelles. PBA-b-PAA solution systems are neither at thermal equilibrium nor completely frozen systems: internal fractionation of individual aggregates can occur. (C) 2007 Elsevier Inc. All rights reserved.

【 授权许可】

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