(445h) Toward Molecular Engineering of Liquid Crystal Elasticity: Predicting 5CB Elastic Constants
The difficulties associated with laboratory measurement of elastic constants present computational methods as an attractive option for understanding the elastic properties of new molecules. Free energy perturbation (FEP) has emerged as a powerful and effective method to obtain liquid crystal elasticities from molecular simulation. However, to date, this method has only been applied to coarse-grained models. Here, we extend this method to the in silico measurement of molecular 5CB obtained from simulation using a combination of FEP methods. We also demonstrate that bulk elastic constants of molecular models may be efficiently calculated, obtaining values which compare well with available experimental data. Importantly, such methods are able to directly measure modes hard to access in experiment, such as the surface-like saddle splay elastic constant, which has been predicted in many systems to lie outside the positive-definite bounds established by the Ericksen inequalities. This represents a milestone in material property prediction and lays the foundation for computationally-guided molecular design of novel mesogenic compounds.