Biaxial Nematics of Hard Cuboids in an External Field

Abstract

We investigate the phase behavior of colloidal suspensions of board-like particles under the effect of an external field and assess the still disputed occurrence of the biaxial nematic (N${}_{\text{B}}$) liquid crystal phase. The external field promotes the rearrangement of the initial isotropic (I) or uniaxial nematic (N${}_{\text{U}}$) phase and the formation of the N${}_{\text{B}}$ phase. In particular, very weak field strengths are sufficient to spark a direct I-N${}_{\text{B}}$ or N${}_{\text{U}}$-N${}_{\text{B}}$ phase transition at the self-dual shape, where prolate and oblate particle geometries fuse into one. By contrast, forming the N${}_{\text{B}}$ phase at any other geometry requires stronger fields and thus reduces the energy efficiency of the phase transformation. Our simulation results show that self-dual shaped board-like particles with moderate anisotropy are able to form N${}_{\text{B}}$ liquid crystals under the effect of a surprisingly weak external stimulus and suggest a path to exploit low-energy uniaxial-to-biaxial order switching.

5 pages, 3 figures

References in corpus (2)

• Hard competition: stabilizing the elusive biaxial nematic phase in suspensions of colloidal particles with extreme lengths
• Monte Carlo simulation of binary mixtures of hard colloidal cuboids