Chiral symmetry-breaking in C-shaped lock-and key colloids: Monte Carlo simulation studies

We model aspherical lock-and-key colloids to explore fundamental mechanisms driving chiral symmetry-breaking and chiral amplification. Recent experiments by Wang and Mason [1] demonstrated that achiral C-shaped colloidal particles form both right- and left-handed dimers, a form of chiral symmetry-breaking. We explore this phenomenon via Monte Carlo simulation of hard C-shaped particles confined to a plane. We calculate the equilibrium constant associated with dimerization and its dependence on osmotic pressure, and find qualitative agreement with experiment. We find that like-signed dimers tend to phase segregate, and that larger clusters display locally crystalline order. We examine kinetic mechanisms driving chiral phase segregation, and speculate that the mechanism observed here may be related to spontaneous chiral phase separation in other systems such as bent-core liquid crystals. These results provide new insight into mechanisms of chiral symmetry-breaking, chiral amplification, and possible origins of biological homochirality. [1] P.-Y. Wang and T.G. Mason, J. Am. Chem. Soc. 137 15308 (2015).