Long-time Behavior and Different Shear Regimes in Quenched Binary Mixtures

The dependence on applied shear of the morphological and rheological properties of diffusive binary systems after a quench from the disordered state into the coexistence region is investigated. In particular the behavior of the late-time transversal size of domains L-y and of the maximum of excess viscosity (Delta eta)(M) is considered. Numerical results show the existence of two regimes corresponding to weak and strong shear separated by a shear rate of the order of gamma(c)similar to 1/t(D) where t(D) is the diffusive time. L-y and (Delta eta)(M) behave as L-y similar to gamma(-alpha) and (Delta eta)(M)similar to gamma(nu) with alpha=alpha(s)=0.18 +/- 0.02, nu=nu(s)=-2.00 +/- 0.01 and alpha=alpha(w)=0.25 +/- 0.01, nu=nu(w)=-0.68 +/- 0.04 in the strong- and weak-shear regimes, respectively. Differently from what was found in systems with fluctuating velocity field, it is confirmed that domains continue to grow at all times.