Computer simulations of linear rigid particles that form chiral superstructures and tilted smectic phases

Abstract

We study the superstructures and phases formed by linear rigid coarse-grained particles using molecular dynamics simulations in the isothermal–isobaric ensemble (NPT). Chiral barrel-shaped and chiral column superstructures self-assemble from these building blocks at low pressures and Monte Carlo parallel tempering and energy minimization simulations demonstrate that chiral superstructures are minima of the potential energy surface for these rigid linear building blocks. At higher pressures the nematic, smectic A, smectic C, and smectic I phases are formed. By varying the spacing between interaction centres in our particles, we show that the discrete nature of the interactions can be tuned to favour both tilted smectic phases and chiral superstructures and our findings point to design rules that can be applied to nanoparticle and colloidal building blocks for the targeted synthesis of the structures we present. Interestingly, superstructural chirality appears as a common theme in systems composed of achiral linear particles with Lennard-Jones interaction sites that are appropriately spaced.