|Title||Hard Competition : Stabilizing the Elusive Biaxial Nematic Phase in Suspensions of Colloidal Particles with Extreme Lengths|
|Author(s)||Dussi, Simone; Tasios, Nikos; Drwenski, Tara; Roij, René Van; Dijkstra, Marjolein|
|Source||Physical Review Letters 120 (2018)17. - ISSN 0031-9007|
|Department(s)||Physical Chemistry and Soft Matter|
|Publication type||Refereed Article in a scientific journal|
We use computer simulations to study the existence and stability of a biaxial nematic Nb phase in systems of hard polyhedral cuboids, triangular prisms, and rhombic platelets, characterized by a long (L), medium (M), and short (S) particle axis. For all three shape families, we find stable Nb states provided the shape is not only close to the so-called dual shape with M=LS but also sufficiently anisotropic with L/S>9,11,14,23 for rhombi, (two types of) triangular prisms, and cuboids, respectively, corresponding to anisotropies not considered before. Surprisingly, a direct isotropic-Nb transition does not occur in these systems due to a destabilization of Nb by a smectic (for cuboids and prisms) or a columnar (for platelets) phase at small L/S or by an intervening uniaxial nematic phase at large L/S. Our results are confirmed by a density functional theory provided the third virial coefficient is included and a continuous rather than a discrete (Zwanzig) set of particle orientations is taken into account.