We report the controlled atom transfer radical polymerization  (ATRP) of a stimuli-responsive ionic liquid surfactant acrylate (ILBr), from both ends of a telechelic poly(propylene oxide) (PPO) macroinitiator, (BrX-PPO-XBr), wherein both ends of the PPO center block are esterified with bromoisobutyryloyl  (BrX). The resulting highly water soluble triblock copolymer, poly(ILBr-b-PO-b-ILBr) is multi-stimuli responsive. This new class of triblocks exhibits classical surface activity in lowering surface tension at the air-water interface and in modifying wetting in waterborne coatings. It also immunizes model colloids against coagulation induced by Debye-H�ckel (indifferent electrolyte) electrostatic screening. The poly(ILBr) endblocks are stimuli-responsive to certain anions, such as hexafluorophosphate, which induces precipitation by converting the hygroscopic imidazolium bromide groups into hydrophobic imidazolium hexafluorophosphate ion pairs. Further, sol-gel thermoreversibility was unexpectedly found as an additional form of supramolecular stimuli-responsiveness. The aqueous triblock thermoreversibly forms a gel phase above a line of LSCTs (lower solution concentration temperatures) at weight fractions above 0.33. The structure of this gel phase has not been established, but it most likely is a lyotropic liquid crystalline phase of poly(ILBr-b-PO-b-ILBr) micelles. This gel phase will be used to template new zeolites.

Ionic liquid-based anion and temperature responsive triblock copolymers

243rd National Meeting (2012)

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