Amphiphilic copolymers with pendant ­carbazolylalkyl groups. ­Effect of polymer structure on ­retardation of self‐quenching

Abstract

A series of amphiphilic polyanions containing (9carbazolyl)alkyl methacrylamide or acrylamide were prepared and their fluorescence properties were compared in organic and aqueous solution. In organic solution, all copolymers exhibited a monomer emission which decayed exponentially, indicating no self-quenching. Decreasing the length of the methylene spacer in the side chain induced the spectral broadening and sharpening, depending on the carbazolyl content in the copolymer. This may be related to the interchromophore interactions and the mobility of chromophores. In H 2 O, by contrast, quenched fluorescence was observed for the copolymers. It should be however noted that acrylamide-type of amphiphilic copolymers, poly(9-carbazolylmethyl-acrylamide-co-sodium 2-acrylamido-2-methylpropanesulfonate), are the least quenched polymers among those reported so far. / Itoh and ShiraiFIGURE 4. Fluorescence spectra of r-CzMMAm(x) (a) and r-CzMAAm(x) (b) in H 2 O: [Cz] residue = 1 Â 10 À5 M; excitation wavelength, 292 nm; the peak intensities are relative to those of the copolymers with x = 1 mol%.