Influence of ionene polyelectrolytes on rheology and photorheology of aqueous micellar cetyltrimethylammonium bromide containing 9-anthracene carboxylic acid

Solubilization of 9-anthracene carboxylic acid (9-AC) in aqueous solutions of [3,12]-ionene and [3,16]-ionene (with bromide counterions) generates hydrobromic acid, as revealed by decreasing pH values. Photodimerization of solubilized 9-AC reverts this effect. Newtonian flow is observed in solutions of ionenes and 9-AC throughout. In contrast, aqueous solutions of cetyltrimethylammonium bromide containing 9-AC exhibit viscoelasticity. The flow behavior of such solutions was studied in the presence of various amounts of [3,16]ionene. The addition of ionenes, as well as the photodimerization of 9-anthracene carboxylic acid, reduced viscoelastic features. A shortening of worm-like micelles is likely to be the molecular origin of the observed effect. Rheological analysis revealed up to four relaxation processes in sheared viscoelastic systems. (C) 1998 Academic Press.