Kinetics of hexagonal cylinders to face-centered cubic spheres transition of triblock copolymer in selective solvent: Brownian dynamics simulation.

The kinetics of the transformation from the hexagonal packed cylinder (hex) phase to the face-centered-cubic (fcc) phase was simulated using Brownian dynamics for an ABA triblock copolymer in a selective solvent for the A block. The kinetics was obtained by instantaneously changing either the temperature of the system or the well-depth of the Lennard-Jones potential. Detailed analysis showed that the transformation occurred via a rippling mechanism. The simulation results indicated that the order-order transformation was a nucleation and growth process when the temperature of the system instantly jumped from 0.8 to 0.5. The time evolution of the structure factor obtained by Fourier transformation showed that the peak intensities of the hex and fcc phases could be fit well by an Avrami equation.