Ionic Liquid modulation of swelling and LCST behavior of N- isopropylacrylamide polymer gels.
Refereed Original Article
The physicochemical properties of free-standing cross-linked poly(N-isopropylacrylamide) (pNIPAAM) gels, generated in the presence of the Ionic Liquids (ILs), 1-ethyl-3-methylimidazolium [C2mIm]+ salts of ethylsulfate [EtSO4]-, dicyanamide [DCA]- , 10 bis(trifluoromethylsulfonyl)imide [NTf2]-, and Trihexyltetradecylphosphonium dycanamide ([P6,6,6,14][DCA]) are described. The Lower Critical Solution Temperature (LCST) of the resulting ionogel was found to vary between 24 – 31 oC. The behaviour of swelling is found to be as high as 31.55% (± 0.47, n = 3) from the initial dehydrated state, while 28.04% (± 0.42, n = 3) shrinking from the hydrated swollen state is observed. For ionogels based on the [DCA]- anion an unexpected complete loss of the shrinking behaviour occurs, attributed to water interactions with the nitrile group of the [DCA]- anion. Scanning Electron Microscopy also reveals distinct ￼15 morphological changes, for example [C2mim][EtSO4] displays water uptake.
Digital Object Identifer (DOI):
Date Accepted for Publication:
Tuesday, 17 December, 2013
Physical Chemistry Chemical Physics
Dublin City University (DCU)
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