The theory based on numerical study of the system of hydrodynamic equations, which includes the director motion, shows that under the influence of crossed electric E and magnetic B fields, the director reorients in such a way that the transient quasiperiodic patterns may arise in microsized nematic volumes if the corresponding distortion mode has the fastest response and thus suppresses all other modes, including uniform ones. It has been shown that there is a threshold value of the amplitude of the thermal fluctuations of the director over the microsized nematic film which provides the nonuniform rotation mode rather than the uniform one, whereas the lower values of the amplitude dominate the uniform mode.
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http://dx.doi.org/10.1103/PhysRevE.109.044704 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States.
Liquid crystals (LCs), when interfaced with chemically functionalized surfaces, can amplify a range of chemical and physical transformations into optical outputs. While metal cation-binding sites on surfaces have been shown to provide a basis for the design of chemoresponsive LCs, the cations have been found to dissociate from the surfaces and dissolve slowly into LCs, resulting in time-dependent changes in the properties of LC-solid interfaces (which impacts the reliability of devices incorporating such surfaces). Here, we explore the use of surfaces comprising metal-coordinating polymers to minimize the dissolution of metal cations into LCs and characterize the impact of the interfacial environment created by the coordinating polymer on the ordering and time-dependent properties of LCs.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Ferroelectric nematic liquid crystals are polar fluids characterized by microscopic orientational ordering and macroscopic spontaneous polarizations. Within these fluids, domain walls that separate regions of different polarizations are ubiquitous. We demonstrate that the π walls in films of the polar fluids consist of twin half-integer surface disclinations spaced horizontally, enclosing a subdomain where the polarization exhibits left- or right-handed π twists across the film.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Key Laboratory of Advanced Catalytic Materials and Technology, Advanced Catalysis and Green Manufacturing Collaborative Innovation Center, Changzhou University, Changzhou 213164, Jiangsu Province, China. Electronic address:
Macro-assembled silicon-based films can be taken into account as a possible anode material for the lithium ion batteries (LIBs) in portable electronics. However, most previously proposed preparation strategies are labor-intensive, intricate, and not appropriate for large-scale manufacturing. Herein, a multifunctional flexible silicon/carbon nanotube/reduced graphene oxide (Si/CNT/rGO) film was fabricated by one-step coating method based on the lyotropic nematic liquid crystals of graphene oxide (GO).
View Article and Find Full Text PDFSmall
December 2024
Department of Physics, Kent State University, Kent, OH, 44242, USA.
The dynamics of swimming bacteria depend on the properties of their habitat media. Recently it is shown that the motion of swimming bacteria dispersed directly in a non-toxic water-based lyotropic chromonic liquid crystal can be controlled by the director field of the liquid crystal. Here, we investigate whether the macroscopic polar order of a ferroelectric nematic liquid crystal (N) can be recognized by bacteria B.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Department of Physics, University of Colorado, Boulder, Colorado, 80309, USA.
We show that stable, freely suspended liquid crystal films can be made from the ferroelectric nematic (N) phase and from the recently discovered polar, lamellar SmZ and SmA phases. The N films display two-dimensional, smectic-like parabolic focal conic textures comprising director/polarization bend that are a manifestation of the electrostatic suppression of director splay in the film plane. In the SmZ and SmA phases, the smectic layers orient preferentially normal to the film surfaces, a condition never found in typical thermotropic or lyotropic lamellar LC phases, with the SmZ films exhibiting focal-conic fan textures mimicking the appearance of typical smectics in glass cells when the layers are oriented normal to the plates, and the SmA films showing a texture of plaquettes of uniform in-plane orientation where both bend and splay are suppressed, separated by grain boundaries.
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