Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight.

ABSTRACT: The effect of a series of sodium salts on the lower critical solution temperature (LCST) of poly(N-isopropylacrylamide), PNIPAM, was investigated as a function of molecular weight and polymer concentration with a temperature gradient microfluidic device under a dark-field microscope. In solutions containing sufficient concentrations of kosmotropic anions, the phase transition of PNIPAM was resolved into two separate steps for higher molecular weight samples. The first step of this two step transition was found to be sensitive to the polymer's molecular weight and solution concentration, while the second step was not. Moreover, the binding of chaotropic anions to the polymer was also influenced by molecular weight. Both sets of results could be explained by the formation of intramolecular a

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC2553222 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature