Comparative physical chemical study of isotactic and atactic poly(styrene sulphonic acid) solutions. Part 3.—Optical rotation and dye binding studies

Abstract

The optical rotatory dispersion curves in the visible region of the quinine salts of isotactic and atactic poly(styrene sulphonic acid) solutions show significant differences. The absorption spectrum of proflavine is changed in an identical manner by the addition of isotactic and atactic polyacids at low sulphonic acid residue/dye ratios. However, at high sulphonic acid residue/dye ratios at room temperature the proflavine has a lower extinction in the presence of the isotactic polyacid than in the presence of the atactic sample. At temperatures above 60°C the different quantitative effects of the isotactic and atactic polyacids on the proflavine absorption diminish. The results are discussed in terms of conformational differences between isotactic and atactic poly(styrene sulphonic acid) molecules in solution.