Kinetics of the orientation transition in the lyotropic lamellar phase

Kinetics of the orientation transition in the triblock copolymer lamellar phase is studied by viscometry. We find that the strain-controlled mechanism dominates the transition kinetics. We propose a possible scenario of the orientation transition from the viewpoint of the dislocation dynamics. We could also evaluate the critical shear rate of the orientation transition by assuming the limiting velocity of the dislocations under shear. evaluated value is in good agreement with the experimental observation. the nucleation of the dislocations might be necessary for the orientation transition.