Kinetics of morphological transitions between mesophases*

We investigate the dynamics of morphological transitions between mesoscopic structures on the basis of the model equation for microphase separation of block copolymers. The phase diagram for the modulated structures is obtained by means of the single-wavenumber approximation. In order to study the time evolution of domains, we derive a coupled set of equations for the amplitudes of the modulated structures in the weak-segregation regime. Simulations of the transitions between lamellar and hexagonal structures are carried out in two dimensions and the results are compared with the theory. Simulations in three dimensions are also presented.