Title: Stimuli Responsive Poly(1-[11-acryloylundecyl]-3-methyl-imidazolium bromide): Dewetting and Nanoparticle Condensation Phenomena

Author: Ma XM; Ashaduzzaman M; Kunitake M; Crombez R; Texter J; Slater L; Mourey T

Journal: LANGMUIR, 2011, V27, N11 (JUN 7), P7148-7157

Abstract: A stimuli-responsive homopolymer poly(ILBr) is fabricated via a "two-phase" atom transfer radical polymerization (ATRP) process, where ILBr stands for the reactive ionic liquid surfactant, 1-[11-acryloylundecyl]-3-methyl-imidazolium bromide. An extraordinarily wide molecular weight distribution (PDI = 6.0) was obtained by introducing the initiator (4-bromomethyl methyl benzoate) in a heterogeneous two-phase process. The molecular weight distribution of poly(ILBr) was characterized by size-exclusion chromatography (SEC). The resulting homopolymer was found to be surface active and stimuli responsive. Poly(ILBr) films coated on quartz exhibit stimuli-responsive dewetting after ion exchange of Br- by PF6-. This dewetting phenomenon can be understood in chain segmental terms as a stimuli-induced structural relaxation and appears to be the first such reported stimuli-responsive polymeric dewetting. Titrating aqueous poly(ILBr) with aqueous bis(2-ethylhexyl)sulfosuccinate induces nanophase separation and results in the condensation of nanoparticles 30-60 nm in diameter. © 2011 American Chemical Society.