We propose a general formalism to characterize orientational frustration of smectic liquid crystals in confinement by interpreting the emerging networks of grain boundaries as objects with a topological charge. In a formal idealization, this charge is distributed in pointlike units of quarter-integer magnitude, which we identify with tetratic disclinations located at the end points and nodes. This coexisting nematic and tetratic order is analyzed with the help of extensive Monte Carlo simulations for a broad range of two-dimensional confining geometries as well as colloidal experiments, showing how the observed defect networks can be universally reconstructed from simple building blocks. We further find that the curvature of the confining wall determines the anchoring behavior of grain boundaries, such that the number of nodes in the emerging networks and the location of their end points can be tuned by changing the number and smoothness of corners, respectively.
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http://dx.doi.org/10.1103/PhysRevLett.127.198001 | DOI Listing |
Soft Matter
January 2025
Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA.
The current intense study of ferroelectric nematic liquid crystals was initiated by the observation of the same ferroelectric nematic phase in two independently discovered organic, rod-shaped, mesogenic compounds, RM734 and DIO. We recently reported that the compound RM734 also exhibits a monotropic, low-temperature, apolar phase having reentrant isotropic symmetry (the I phase), the formation of which is facilitated to a remarkable degree by doping with small (below 1%) amounts of the ionic liquid BMIM-PF. Here we report similar phenomenology in DIO, showing that this reentrant isotropic behavior is not only a property of RM734 but is rather a more general, material-independent feature of ferroelectric nematic mesogens.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Departament de Física, Campus Nord B4-B5, Universitat Politècnica de Catalunya, E-08034 Barcelona, Spain.
We predict that ultracold bosonic dipolar gases, confined within a multilayer geometry, may undergo self-assembling processes, leading to the formation of chain gases and solids. These dipolar chains, with dipoles aligned across different layers, emerge at low densities and resemble phases observed in liquid crystals, such as nematic and smectic phases. We calculate the phase diagram using quantum Monte Carlo methods, introducing a newly devised trial wave function designed for describing the chain gas, where dipoles from different layers form chains without in-plane long-range order.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
The creation of anisotropic nanoparticles (NPs) by polymerization and/or self-assembly (SA) has significantly promoted the applications of polymer nanomaterials in many fields. However, polymer nanorods are not easily accessible via conventional polymerization or SA. Here we report a one-step route to synthesize single-domain smectic liquid crystalline (LC) nanorods utilizing oriented attachment (OA) that was usually found in the synthesis of inorganic NPs, synchronized with polymerization and SA.
View Article and Find Full Text PDFPhys Rev E
November 2024
William H. Miller III Department of Physics and Astronomy, Johns Hopkins University, Baltimore 21218, USA.
Composite materials made of polymers and liquid crystals have been widely employed in smart windows, optical filters, and bistable displays. However, it is often difficult to decipher the role of the polymer network architecture on the alignment and the texture of liquid crystals. In this study, we use a simple model system where a small amount of polymerizable liquid crystalline monomer is mixed in a liquid crystal that exhibits both a smectic phase and a cholesteric phase with a large helical pitch.
View Article and Find Full Text PDFSoft Matter
January 2025
School of Physics and Astronomy, James Clerk Maxwell Building, Peter Guthrie Tait Road, The University of Edinburgh, Edinburgh EH9 3FD, UK.
In this article, we investigate the dynamics of self-organised suspensions formed by rod-like fd virus colloids. Two methods have been employed for analysing fluorescence microscopy movies: single particle tracking (SPT) in direct space and differential dynamic microscopy (DDM) in reciprocal space. We perform a quantitative analysis on this anisotropic system with complex diffusion across different self-assembled states, ranging from dilute and semi-dilute liquids to nematic and smectic organisations.
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