Acceleration of Liquid-Crystalline Phase Transition Simulations Using Selectively Scaled and Returned Molecular Dynamics.

The molecular dynamics (MD) technique to accelerate simulation of phase transition to liquid-crystalline (LC) phases is demonstrated on the model LC system 4-octyl-4'-cyanobiphenyl (8CB) smectic A phase. Simulation of a phase transition to a smectic phase is challenging because an intrinsically long simulation time and large system size are required owing to the high order and low onset temperature. Acceleration of the simulated transition of 8CB to the smectic A phase was ultimately achieved by selectively weakening the intermolecular Lennard-Jones interaction of alkyl chains and then returning the scaled interaction to the unscaled one. The total time needed to form the smectic A phase using selectively scaled and returned molecular dynamics (ssrMD) was five times shorter than that when using unscaled MD. Formation of the smectic A phase occurred only when induced polarization from the antiparallel dipole dimer point charge was included in the simulation. The use of ssrMD presented herein is anticipated to accelerate the theoretical development of self-assembled organic materials containing both rigid and flexible moieties, including LC materials.