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Exciton Broadening In Polyaniline Chains During Ion Induced Hydrophobic Collapse And Aggregation, Louis R. Nemzer, Arthur Epstein

Louis R Nemzer

The ion-induced reprecipitation of the emeraldine base form of polyaniline from an aqueous-organic binary solution is a facile method for obtaining polymer nanoparticles and microscale clusters. The hydrophobic collapse and aggregation that accompanies the addition of various cosolutes induces changes in the peak wavelength and linewidth of the main exciton absorption. In particular, we find that the addition of ionic cosoutes leads to a redshifting and broadening of this spectroscopic feature, with divalent coions exhibiting an additional hypsochromic reversal at high concentrations. The denaturant urea, in contrast, causes a blueshift and line-narrowing at all concentrations. Using a quantitative Lorentz fit, …