Kent State University

The University Court of the University of Aberdeen

Oleg D Lavrentovich

Sergij V Shiyanovskii

Andrii B Golovin

Gary D Niehaus

Christopher J Woolverton

Yubing Guo

Qi-Huo Wei

Steven P Schmidt

Steven A Signs

Kathleen J Doane

Chenhui Peng

Jie V Xiang

Oleg Yaroshchuk

Mingxia Gu

Liang-Chy Chien

Tod L Schneider

Dmitry Voloschenko

John M Storey

Andriy Dobrovolskyy

Tomohiro Ishikawa

Israel Esteban Lazo-Martinez

Oleg P Pishnyak

Miao Jiang

Corrie T Imrie

Jong-Chan Lee

Peter Palffy-Muhoray

Hao Yu

Andrii Varanytsia

Kai Sun

Fred Minkowski

Volodymyr Borshch

Daniel A Paterson

Liubov Kreminska

Sergij V Shiyanovsii

Young-Ki Kim

Daniel E Paterson

Darius Subacius

Heung-Shik Park

Vassil G Nazarenko

Yuriy A Nastyshyn

Vassili G Nazarenko

Roman M Vasyuta

Oleksandr P Boiko

Taras Turiv

Ye Yin

A method for aligning molecular orientations of liquid crystals and/or polymeric materials into spatially variant patterns uses metamasks. When non-polarized or circularly polarized light is transmitted through or reflected by the metamasks, spatially varied polarization direction and intensity patterns of light can be generated. By projecting the optical patterns of the metamasks onto substrates coated with photoalignment materials, spatially variant molecular orientations encoded in the polarization and intensity patterns are induced in the photoalignment materials, and transfer into the liquid crystals. Possible designs for the metamask use nanostructures of metallic materials.

Photopatterning of molecular orientations

A method for aligning molecular orientations of liquid crystals and/or polymeric materials into spatially variant patterns uses metamasks. When non-polarized or circularly polarized light is transmitted through or reflected by the metamasks, spatially varied polarization direction and intensity patterns of light can be generated. By projecting the optical patterns of the metamasks onto substrates coated with photoalignment materials, spatially variant molecular orientations encoded in the polarization and intensity patterns are induced in the photoalignment materials, and transfer into the liquid crystals. Possible designs for the metamask use nanostructures of metallic materials (e.g., rectangular nanocuboids of metallic materials arrayed on a transparent substrate).

A lasing device includes an active layer comprising a cholesteric liquid crystal material and a laser dye, and a liquid crystal cell including spaced apart substrates defining a cell gap in which the active layer is disposed. The substrates include electrodes arranged to bias the active layer into an oblique helicoidal (Ch) state. At least one substrate of the liquid crystal cell is optically transparent for a lasing wavelength range of the device.

Electrically tunable laser with cholesteric liquid crystal heliconical structure

A method for controlling self-propelled particles includes providing the particles to a liquid crystalline medium having predesigned local ordering. The method may control at least one of: a local concentration, trajectory, and net flow of self-propelled particles.

Command of active matter by topological defects and patterns

A transport device comprises: a fluid cell comprising parallel substrates; an anisotropic electrolyte disposed in the fluid cell; and electrodes configured to apply an AC electric field to the anisotropic electrolyte disposed in the fluid cell. A substrate of the fluid cell includes a pattern that induces a director distortion pattern in the anisotropic electrolyte disposed in the fluid cell. The director distortion pattern has a gradient configured to induce electrokinetic flow of the anisotropic electrolyte in the fluid cell in response to the AC electric field applied by the electrodes. Cargo, such as particles, gas bubbles, or fluid, is dispersed in the anisotropic electrolyte and transported in the fluid cell by the induced electrokinetic flow of the anisotropic electrolyte. The induced electrokinetic flow may be linear, curvilinear, circular so as to induce mixing, depending on the predesigned director pattern. The director pattern might be nonsingular (defect free) or may contain defects such as disclinations that produce pumping effects and can trap cargo at a core of the disclination.

Liquid crystals with patterned molecular orientation as an electrolytic active medium

A liquid crystal cell includes substrates defining a gap and electrodes having one of (i) an in-plane geometry generating an electric field parallel with the substrates and (ii) a top-down geometry generating an electric field across the gap between the two spaced apart substrates. A liquid crystal material disposed in the gap between the substrates comprises a chiral nematic material formed by a mixture of: 1-(4-cyanobiphenyl-4'-yl)-6-(4-cyanobiphenyl-4&#x2032;-yloxy)hexane (CB6OCB) or &#x3b1;,&#x3c9;-bis(4,4-cyanobiphenyl)nonane (CB9CB) dimeric liquid crystal material; at least one additional dimeric liquid crystal material; and a chiral dopant. The liquid crystal material within an operational range of electric field applied by the electrodes exhibits a heliconical state with an oblique angle helicoid director whose helicoid axis is oriented parallel with the electric field and whose helicoid pitch is sized to provide diffraction or Bragg reflection of light in a spectral range of interest impinging on one of the substrates of the liquid crystal cell.

Field induced and controlled heliconical structure of cholesteric liquid crystal

A diffraction grating comprises a liquid crystal (LC) cell configured to apply an electric field through a cholesteric LC material that induces the cholesteric LC material into a heliconical state with an oblique helicoid director. The applied electric field produces diffracted light from the cholesteric LC material within the visible, infrared or ultraviolet. The axis of the heliconical state is in the plane of the liquid crystal cell or perpendicular to the plane, depending on the application. A color tuning device operates with a similar heliconical state liquid crystal material but with the heliconical director axis oriented perpendicular to the plane of the cell. A power generator varies the strength of the applied electric field to adjust the wavelength of light reflected from the cholesteric liquid crystal material within the visible, infrared or ultraviolet.

Field induced heliconical structure of cholesteric liquid crystal

An optical modulator includes a liquid crystal cell containing liquid crystal material having liquid crystal molecules oriented along a quiescent director direction in the unbiased state, and a voltage source configured to apply an electric field to the liquid crystal material wherein the direction of the applied electric field does not cause the quiescent director direction to change. An optical source is arranged to transmit light through or reflect light off the liquid crystal cell with the light passing through the liquid crystal material at an angle effective to undergo phase retardation in response to the voltage source applying the electric field. The liquid crystal material may have negative dielectric anisotropy, and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is transverse to the quiescent director direction. Alternatively, the liquid crystal material may have positive dielectric anisotropy and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is parallel with the quiescent director direction.

Nanosecond liquid crystalline optical modulator

A nanoparticle composition, a device including the nanoparticle composition, and a method thereof are provided. The composition comprises nanoparticles such as Gold nanorods (NR) and electrically charged self-assembled molecular aggregates such as disodium chromoglycate (DSCG) in a common solvent such as water. The nanoparticles are assembled as, for example, side-by-side and end-to-end assemblies of nanorods, through a non-covalent interaction such as anisotropic electrostatic interaction with the electrically charged self-assembled molecular aggregates. The invention can be used in a cloaking device, a biological sensing device, a drug delivery, a meta material, a negative index material, an enhanced imaging device, and a device for solar energy conversion, and exhibits many merits such as simpler process without the need of a covalent bonding between the nanoparticles, different manners of nanoparticles assembling with same linker, higher thermal stability, cost effectiveness, and capability of gradual controlling of the degree of NR assembly, among others.

Nanoparticle composition, a device and a method thereof

A method of electrophoretic movement of liquid droplets/gas bubbles through a liquid crystal utilizes a direct (DC) or alternating (AC) electric field that is applied along the liquid crystal director (for liquid crystals with a positive dielectric anisotropy) or perpendicular to the director (for liquid crystals with a negative dielectric anisotropy). A perpendicular or tilted orientation of the liquid crystal molecules at the surface of the liquid droplet/gas bubble causes distortions, such that the fore-aft (or left-right) symmetry of the liquid droplet/gas bubble is broken. The asymmetric orientation of the liquid crystal around the liquid droplet/gas bubble allows both charged and neutral particles to be transported, even when the liquid droplets/gas bubbles themselves are perfectly symmetric (spherical).

Method for electrophoresis in liquid crystals

A method of electrophoretic movement of particles through a liquid crystal utilizes a direct (DC) or alternating (AC) electric field that is applied along the liquid crystal director (for liquid crystals with a positive dielectric anisotropy) or perpendicular to the director (for liquid crystals with a negative dielectric anisotropy). A perpendicular or tilted orientation of the liquid crystal molecules at the surface of the particle causes distortions, such that the fore-aft (or left-right) symmetry of the particle is broken. The asymmetric orientation of the liquid crystal around the particle allows both charged and neutral particles to be transported, even when the particles themselves are perfectly symmetric (spherical).

Electrically reconfigurable metamaterial with spatially varied refractive index is proposed for applications such as optical devices and lenses. The apparatus and method comprises a metamaterial in which the refractive indices are modified in space and time by applying one or more electric fields. The metamaterials are electrically controllable and reconfigurable, and consist of metal (gold, silver, etc.) particles of different shapes, such as rods, with dimension much smaller than the wavelength of light, dispersed in a dielectric medium. The metamaterial is controlled by applying a non-uniform electric field that causes two effects: (1) It aligns the metallic anisometric particles with respect to the direction of the applied electric field and (2) It redistributes particles in space, making their local concentration position dependent.

Methods and apparatus for controlling dispersions of nanoparticles

The invention provides a liquid crystal cell and method thereof. The cell comprises two opposed substrates and a surfactant-free lyotropic chromonic liquid crystals (LCLC) material disposed therebetween. By using an ammonium compound with LCLC or surface treatment on the substrates, the alignment of the LCLC material can be manipulated as a homeotropic bulk alignment; or a hybrid bulk alignment in which the LCLC alignment is changed from homeotropic bulk alignment in the vicinity of one substrate to planar alignment in the vicinity of another substrate. The cell can be used in biosensing, detection and amplification of ligands, optical devices, and photovoltaics etc.

Homeotropic and hybrid bulk alignment of lyotropic chromonic liquid crystals

A liquid crystalline optical medium includes polymer stabilized liquid crystal material. The polymer stabilized liquid crystal material includes a short pitch cholesteric liquid crystal material stabilized by a polymer material. The effective phase retardation of the polarization independent liquid crystal optical medium can be controlled by external (for example, electric and magnetic) fields.

Electronically-controllable polarization independent liquid crystal optical medium and devices using same

The present invention comprises a device and method for ordering molecules of lyotropic chromonic liquid crystals to aligned structure of a dried film. An example of an aligned film may be transparent to visible light but not transparent to polarized light in the ultraviolet and/or infrared portions of the electromagnetic spectrum. A shearing device having a shearing tool and a repelling pad may repel the solvent and provide a shear force to shear the LCLC dissolved in the solvent as a film on the surface of a substrate. A method of making an aligned lyotropic chromonic liquid crystal-based film comprises providing a mixture of a lyotropic chromonic liquid crystal material in a solvent for the liquid crystal material, applying the mixture to a substrate, shearing the lyotropic chromonic liquid crystal with a shearing device and removing the solvent to produce an aligned lyotropic chromonic liquid crystal-based film.

Methods and apparatus to produce aligned film of lyotropic chromonic liquid crystals

Growing community of inventors

Kent, OH, United States of America

Oleg D Lavrentovich