Steady
shear and rheo-optical experimental data measured in several micellar solutions, demonstrate the existence of a non-equilibrium critical point (
necp) in the
shear banding
flow of wormlike micellar solutions by the following evidence: (1) the disappearance of the coexistence of two steady
banded fluids at the
necp, (2) the curves of the reduced
shear stress versus reduced
shear rate become anti-symmetric in the neighborhood of the non-equilibrium critical point; (3)
flow birefringence increases considerably in the neighborhood of the
necp; (4) the divergence of non-equilibrium thermodynamic properties (isothermal
flow susceptibility and the normalized heat dissipation), as the
necp is approached; and (5) the existence of a finite correlation dimension calculated from time analysis of birefringence data, and positive Lyapunov exponents, which are consistently smaller than the embedding dimension.
The predictions of the BMP model follow these trends closely.