Twist-bend and splay-bend order induced by excluded-volume interactions

Onsager's model of hard spherocylinders demonstrated the isotropic-nematic phase transition, revealing that molecular elongation alone induces liquid crystalline order. Subsequent research expanded this understanding to various anisotropic shapes, including banana-shaped molecules. Recent studies have reported a chiral twist-bend nematic phase in achiral systems [Greco et al. (2015), Phys. Rev. Let., 115(14), 147801]. DFT calculations [Greco et al. (2014), Soft Matter, 10(46), 9318-9323] showed how crescent and cone-like shapes affect elastic constants, confirming earlier observations made by Meyer. Our research group investigated the stability of modulated liquid crystalline phases in crescent and cone-like systems via Monte Carlo simulations. We found stable twist-bend nematic, splay-bend smectic and columnar phases for crescent-like shapes. When subjected to confinement between walls or when two domains with opposite chiralities were juxtaposed, various phases emerged, including splay-bend nematic. While simulations did not confirm DFT predictions for cone-like molecules, we observed crystalline phases with non-trivial domain configurations.