Chemistry and Physics Faculty Articles

Title

Exciton Peak Redshifting and Broadening in Polyaniline Chains During Ion-Induced Hydrophobic Collapse and Aggregation

Document Type

Article

Publication Date

11-2011

Keywords

Polyaniline, Exciton, Spectroscopy, Polymer aggregation, Hydrophobic collapse

Publication Title

Synthetic Metals

ISSN

0379-6779

Volume

161

Issue/No.

21-22

First Page

2284

Last Page

2288

Peer Reviewed

1

Abstract

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, we show how the redshifting and broadening of this spectral feature can be attributed, at least in part, to the forced planarization of the polymer chains in the collapsed state.

Comments

©2011 Elsevier B.V. All rights reserved.

Additional Comments

IGERT grant #: 0221678; NS EC grant #: EEC-0425626

DOI

10.1016/j.synthmet.2011.08.034

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