We use computer simulations to study the existence and stability of a biaxial nematic N_{b} 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 N_{b} states provided the shape is not only close to the so-called dual shape with M=sqrt[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-N_{b} transition does not occur in these systems due to a destabilization of N_{b} 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.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevLett.120.177801 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Atomistic insights into liquid crystals of board-like molecules via molecular dynamics simulation.
J Chem Phys
December 2024
Department of Applied Physics, University of Granada, Avenida Fuente Nueva s/n, 18071 Granada, Spain.
As the temperature decreases, rigid anisotropic molecules that usually incorporate polar groups, aromatic rings or multiple bonds, orient along a common direction, eventually forming liquid-crystalline phases under specific thermodynamic conditions. This study explores the phase behavior and dynamics of board-shaped mesogens with a 1,4,5,8-tetraphenyl-anthraquinone core and four lateral arms forming an oligo(phenyleneethynylene) scaffold. These molecules are promising candidates for forming the elusive biaxial nematic phase.
View Article and Find Full Text PDFExploring noisy Jeffery orbits: A combined Fokker-Planck and Langevin analysis in two and three dimensions.
Phys Rev E
October 2024
Institute for Solid State Physics and Optics, HUN-REN Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary.
Article Synopsis
- The study focuses on the behavior of nonspherical particles, particularly elongated ones, in shear flow, building on the historical work of Jeffery which described their motion.
- It employs Langevin simulations and the Fokker-Planck equation to analyze how these particles respond to noise and calculates key parameters that represent their ordering behaviors, such as nematic ordering and biaxiality.
- The research finds that as noise decreases or Péclet number increases, nematic order improves, while biaxiality peaks at a certain value, and it also reveals that particles in 3D rotate faster than in 2D under the same noise conditions.
Emergent biaxiality in chiral hybrid liquid crystals.
Nat Commun
November 2024
Department of Physics and Chemical Physics Program, University of Colorado, Boulder, CO, USA.
Biaxial nematic liquid crystals are fascinating systems sometimes referred to as the Higgs boson of soft matter because of experimental observation challenges. Here we describe unexpected states of matter that feature biaxial orientational order of colloidal supercritical fluids and gases formed by sparse rodlike particles. Colloidal rods with perpendicular surface boundary conditions exhibit a strong biaxial symmetry breaking when doped into conventional chiral nematic fluids.
View Article and Find Full Text PDFMesogen Organizations in Nematic Liquid Crystal Elastomers Under Different Deformation Conditions.
Small
November 2024
Department of Mechanical Engineering, University of Colorado Denver, Denver, CO, 80217, USA.
Liquid crystal elastomers (LCEs) exhibit unique mechanical properties of soft elasticity and reversible shape-changing behaviors, and so serve as potentially transformative materials for various protective and actuation applications. This study contributes to filling a critical knowledge gap in the field by investigating the microscale mesogen organization of nematic LCEs with diverse macroscopic deformation. A polarized Fourier transform infrared light spectroscopy (FTIR) tester is utilized to examine the mesogen organizations, including both the nematic director and mesogen order parameter.
View Article and Find Full Text PDFThe effect of particle geometry and initial configuration on the phase behavior of twisted convex -prisms.
Soft Matter
July 2024
Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany.
Article Synopsis
- The study focuses on the phase behavior of twisted convex prisms (with shapes defined by specific geometries) utilizing Monte Carlo simulations for prisms of dimensions 3 and 4.
- Strong twisting of these prisms prevents biaxial phases from forming and instead stabilizes uniaxial nematic and smectic phases.
- The research highlights how the aspect ratio of the prisms affects phase behavior, showing that higher aspect ratios lead to biaxial phases while lower ratios relate to phases similar to hard cylinders.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!