The study on self-assembly structure of diblock copolymer melts using molecular dynamics with soft potential and potential recovery

Various self-assembled microstructures with block copolymers are obtained by using molecular dynamics (MD) simulation method. Typically, it requires substantial computational cost to prepare initial configurations of various self-assembled structures with MD because of topological constraints. Furthermore, manual preparation often becomes a complicated and time-consuming procedure even for a lamellar phase, not to mention complex phases, such as a bi-continuous gyroid phase. The problem may be overcome by introducing a soft potential to allow the system to reach a self-assembled state fast. Once a self-assembled microstructure is established, the normal potential, like Weeks-Chandler-Andersen (WCA) potential, is reinstated and equilibration runs are performed to get equilibrated melts and calculate both static and dynamic properties of the microstructures. Various equilibrated phase structures—including S (spherical), H (hexagonal), G (gyroid), and L (lamellar) phases—are obtained and, to verify our method, static and dynamic properties of the lamellar phase are analyzed with previous results.