RHEOLOGY OF LYOTROPIC LAMELLAR PHASES

The rheological behaviour of lyotropic lamellar phases is studied as a function of the membrane repeating distance. The steady-state rheology is described as a consequence of the so-called orientation diagram described previously. Three distinct regions of different orientations are described, which are separated by two out-of-equilibrium transitions. We show that these transitions can be either discontinuous (subcritical) or continuous. In one of these transitions, one can go continuously from one regime to the other through a bifurcation point.