Kinetics of Hexagonal Cylinders to Face-centered Cubic Spheres Transition of Triblock Copolymer in Selective Solvent: Brownian Dynamics Simulation

TL;DR

This study uses Brownian Dynamics simulations to investigate the transformation kinetics of triblock copolymers from hexagonal cylinders to face-centered cubic spheres, revealing a nucleation and growth process with rippling mechanisms.

Contribution

It provides detailed simulation insights into the order-order transition mechanism of triblock copolymers under temperature or potential changes, highlighting a nucleation and growth process.

Findings

Transformation occurs via rippling mechanism.

Order-order transition is a nucleation and growth process.

Peak intensities follow an Avrami equation.

Abstract

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 (OOT) 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.