RHEOLOGICAL BEHAVIOR OF WORM-LIKE MICELLES - EFFECT OF ELECTROSTATIC INTERACTIONS

Both linear and non-linear viscoelasticity experiments have been performed in semi-dilute micellar aqueous solutions of ethanediyl-alpha,omega-bis (dodecylmethylammonium bromide) as a function of solution chloride (NaCl) concentration. The results suggest that both linear and non-linear properties are affected by the electrostatic interactions. In particular, the plateau modulus GI and the ratio sigma(m)/G(infinity)('), where sigma(m) represents the plateau value in a stress-shear rate experiment, are enhanced as the electrostatic interactions are screened by addition of salt. The zero-shear viscosity is lowered upon addition of NaCl, due Likely to an exchange of the Cl- ions with the Br- counterions.