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

Both linear and non-linear viscoelasticity experiments have been perfo rmed in semi-dilute micellar aqueous solutions of ethanediyl-alpha,ome ga-bis (dodecylmethylammonium bromide) as a function of solution chlor ide (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 screen ed by addition of salt. The zero-shear viscosity is lowered upon addit ion of NaCl, due Likely to an exchange of the Cl- ions with the Br- co unterions.