Controlling Materials Architecture on the Nanometer-Scale: PPV Nanocomposites Via Polymerizable Lyotropic Liquid Crystals

1997 ◽  
Vol 488 ◽  
Author(s):  
Ryan C. Smith ◽  
Hai Deng ◽  
Walter M. Fischer ◽  
Douglas L. Gin
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Liquid Crystalline ◽  
Lyotropic Liquid Crystals ◽  
Nanometer Scale ◽  
General Strategy ◽  
Hexagonal Symmetry ◽  
The Matrix ◽  
Hexagonal Arrangement ◽  
Lock In

AbstractWe have developed a general strategy for the construction of ordered nanocomposites with hexagonal symmetry, using polymerizable lyotropic (i.e., amphiphilic) liquid crystals. In this approach, self-organizing lyotropic liquid-crystalline monomers are used to form an ordered template matrix in the presence of a reactive hydrophilic solution. Subsequent photopolymerization to lock-in the matrix architecture, followed by initiation of chemistry within the ordered hydrophilic domains to afford solid-state fillers, yields the anisotropic nanocomposites. Composites have been synthesized that have a regular hexagonal arrangement of extended poly(p-phenylenevinylene) (PPV) domains, with a regular interchannel spacing of 4 nm. The photoluminescence of these materials is significantly altered from that of bulk PPV. The dimensions of these nanocomposites can be tuned by varying the size of the hydrophobic tails and/or the nature of the counterion associated with the hydrophilic headgroup of the monomer.

scholarly journals Artificial colloidal liquid metacrystals by shearing microlithography

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanqiu Jiang ◽  
Fan Guo ◽  
Zhen Xu ◽  
Weiwei Gao ◽  
Chao Gao
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Molecular Size ◽  
Digital Design ◽  
Lyotropic Liquid Crystals ◽  
Colloidal Systems ◽  
Extended Form ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials ◽  
External Stimuli

Abstract Meta-periodicity beyond intrinsic atomic and molecular order, such as metacrystalline and quasicrystalline lattices, exists in solids, but is usually elusive in lyotropic liquid crystals for its energetic instability. The stable meta-periodicity in lyotropic liquid crystals in the absence of external stimuli remains unexplored, and how to achieve it keeps a great challenge. Here we create lyotropic liquid crystals with stable meta-periodicity in a free state, coined as liquid metacrystals, in colloidal systems by an invented shearing microlithography. The meta-periodicity is dynamically stabilized by the giant molecular size and strong excluded volume repulsion. Liquid metacrystals are designed to completely cover a library of symmetries, including five Bravais and six quasicrystalline lattices. Liquid metacrystal promises an extended form of liquid crystals with rich meta-periodicity and the shearing microlithography emerges as a facile technology to fabricate liquid meta-structures and metamaterials, enabling the digital design of structures and functionalities of liquid crystalline materials.

scholarly journals Lyotropic Liquid Crystals from Colloidal Suspensions of Graphene Oxide

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 455 ◽  
Author(s):  
Adam P. Draude ◽  
Ingo Dierking
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Colloidal Particles ◽  
Colloidal Suspensions ◽  
Lyotropic Liquid Crystals ◽  
Nanoscience And Nanotechnology ◽  
And Behavior

Lyotropic liquid crystals from colloidal particles have been known for more than a century, but have attracted a revived interest over the last few years. This is due to the developments in nanoscience and nanotechnology, where the liquid crystal order can be exploited to orient and reorient the anisotropic colloids, thus enabling, increasing and switching the preferential properties of the nanoparticles. In particular, carbon-based colloids like carbon nanotubes and graphene/graphene–oxide have increasingly been studied with respect to their lyotropic liquid crystalline properties over the recent years. We critically review aspects of lyotropic graphene oxide liquid crystal with respect to properties and behavior which seem to be generally established, but also discuss those effects that are largely unfamiliar so far, or as of yet of controversial experimental or theoretical outcome.

Fluorescent Hexacatenar Liquid Crystals

1999 ◽  
Vol 560 ◽  
Author(s):  
Ben Hoag ◽  
Douglas L. Gin ◽  
Udo Theissl ◽  
Egbert Zojer ◽  
Guenther Leising
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Emission Spectroscopy ◽  
Liquid Crystalline ◽  
Photophysical Properties ◽  
Optoelectronic Properties ◽  
Blue Luminescence ◽  
Photoluminescence Excitation ◽  
Site Selective

ABSTRACTA novel family of phasmidic liquid crystals incorporating an oligo(ρ-phenylenevinylene) core was produced. These compounds exhibit blue luminescence in both solution and the solid state. The emission profiles are influenced by the degree of organization in the solid state. The snthesis and liquid-crystalline behavior of these compounds will be discussed. Their photophysical properties, as studied by c.w. photoluminescence excitation, emission spectroscopy, and site selective spectroscopy, as well as their optoelectronic properties will be presented.

scholarly journals Kernresonanzen in kristallinen Flüssigkeiten und in kristallinflüssigen Lösungen. Teil I

1964 ◽  
Vol 19 (2) ◽  
pp. 161-171 ◽  
Author(s):  
Alfred Saupe
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Dipole Interaction ◽  
Coupling Constants ◽  
Spin Coupling ◽  
The Matrix ◽  
Average Spin ◽  
Spin Coupling Constants ◽  
Magnetic Resonances ◽  
Spin Spin Coupling

A theoretical study of nuclear magnetic resonances in liquid crystals and in liquid crystalline solutions is given. The average ordering of the molecules in liquid crystals, as far as it is of importance for nuclear resonance researches, can be described by a symmetrical matrix. With the help of this matrix the coupling constants of the effective average spin HAMiLTONIAN can be expressed by the constants belonging to a fixed molecular orientation. For experimental work solutions in nematic liquid crystals are most useful. In such solutions high resolution spectra of the orientated solute molecules can be gained without any disturbance by intermolecular nuclear dipole-dipole interaction. Precise informations can be obtained on the intra-molecular dipole-dipole interaction, the anisotropy of chemical shift, and the quadrupole interaction. The matrix of order can be determined if the molecular structure is sufficiently known. In favorable cases the absolute sign of the indirect spin-spin coupling constants can also be determined.

scholarly journals Exploration of immobilization conditions of cellulosic lyotropic liquid crystals in monomeric solvents by in situ polymerization and achievement of dual mechanochromism at room temperature

RSC Advances ◽  
2018 ◽  
Vol 8 (44) ◽  
pp. 24724-24730 ◽  
Author(s):  
K. Miyagi ◽  
Y. Teramoto
Keyword(s):  
Liquid Crystals ◽  
Polymer Composites ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
Synthetic Polymer ◽  
Lyotropic Liquid Crystals ◽  
Liquid Crystalline Structure ◽  
Cholesteric Liquid Crystalline

We obtained cellulosic/synthetic polymer composites incorporating a cholesteric liquid crystalline structure by in situ polymerization and accomplished dual mechanochromism at room temperature.

Fluorescent Hexacatenar Liquid Crystals

1999 ◽  
Vol 558 ◽  
Author(s):  
Ben Hoag ◽  
Douglas L. Gin
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Emission Spectroscopy ◽  
Liquid Crystalline ◽  
Photophysical Properties ◽  
Optoelectronic Properties ◽  
Blue Luminescence ◽  
Photoluminescence Excitation ◽  
Site Selective

ABSTRACTA novel family of phasmidic liquid crystals incorporating an oligo(p-phenylenevinylene) core was produced. These compounds exhibit blue luminescence in both solution and the solid state. The emission profiles are influenced by the degree of organization in the solid state. The snthesis and liquid-crystalline behavior of these compounds will be discussed. Their photophysical properties, as studied by c.w. photoluminescence excitation, emission spectroscopy, and site selective spectroscopy, as well as their optoelectronic properties will be presented.

scholarly journals Cubic and Hexagonal Liquid Crystals as Drug Delivery Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Yulin Chen ◽  
Ping Ma ◽  
Shuangying Gui
Keyword(s):  
Drug Delivery ◽  
Liquid Crystals ◽  
Drug Delivery Systems ◽  
Liquid Crystalline ◽  
Hexagonal Phase ◽  
Delivery Systems ◽  
Lyotropic Liquid Crystals ◽  
Cubic Phase ◽  
Sustained Drug Release ◽  
Wide Range

Lipids have been widely used as main constituents in various drug delivery systems, such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, and lipid-based lyotropic liquid crystals. Among them, lipid-based lyotropic liquid crystals have highly ordered, thermodynamically stable internal nanostructure, thereby offering the potential as a sustained drug release matrix. The intricate nanostructures of the cubic phase and hexagonal phase have been shown to provide diffusion controlled release of active pharmaceutical ingredients with a wide range of molecular weights and polarities. In addition, the biodegradable and biocompatible nature of lipids demonstrates the minimum toxicity and thus they are used for various routes of administration. Therefore, the research on lipid-based lyotropic liquid crystalline phases has attracted a lot of attention in recent years. This review will provide an overview of the lipids used to prepare cubic phase and hexagonal phase at physiological temperature, as well as the influencing factors on the phase transition of liquid crystals. In particular, the most current research progresses on cubic and hexagonal phases as drug delivery systems will be discussed.

scholarly journals Colloidal Lyotropic Liquid Crystalline Phases of Two-Dimensional Nanoparticles of Layered Hybrid Organic-Inorganic Metal Halide Perovskites

2021 ◽  
Author(s):  
PEI-XI WANG
Keyword(s):  
Liquid Crystals ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Metal Halide ◽  
Lyotropic Liquid Crystals ◽  
Two Dimensional ◽  
Halide Anion ◽  
Crystalline Phases ◽  
Liquid Crystalline Phases ◽  
Halide Perovskites

Lyotropic liquid crystals are fluids with macroscopic anisotropic structures formed by the self-assembly of nonspherically-symmetric mesogenic molecules or nanoparticles. Here, lyotropic liquid crystalline phases with discotic-nematic orderings were observed in colloidal dispersions of hexagonal-shaped nanoplatelets of two-dimensional layered hybrid organic-inorganic metal halide perovskites (with formula A<sub>2</sub>BX<sub>4</sub> where A<sup>1+</sup> is an organic ammonium cation, B<sup>2+</sup> is a divalent metal cation, and X<sup>1-</sup> is a halide anion) synthesized via microcrystallization by mixing precursor solutions with antisolvents containing surfactants, which showed semiconducting properties such as blue to green photoluminescence. As nanocrystalline perovskites are compositionally (transition metals like manganese, copper or europium as octahedral unit centers, mixed halides, organic spacers with chirality, etc.), microscopic structurally (three-, two-, or one-dimensional), and geometrically (nanosheets or nanorods) adjustable, liquid crystals with different phase behaviors and physical features (e.g., paramagnetism) may be systematically developed using this method.<br>

scholarly journals Thermal and Optical Characterization of Polymer-Dispersed Liquid Crystals

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Robert A. Shanks ◽  
Daniel Staszczyk
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
Uv Curable ◽  
Polymer Dispersed Liquid Crystals ◽  
The Matrix ◽  
Polymer Dispersed ◽  
Acrylate Resin ◽  
Display Order

Liquid crystals are compounds that display order in the liquid state above the melting temperature and below the mesogenic isotropic temperature. Polymer-dispersed liquid crystals (PDLCs) are composite materials in which liquid crystalline material is dispersed within a polymer matrix to form micron-sized droplets. The aim was to prepare several cholesteryl esters or alkoxybenzoic acid PDLCs and characterise thermal and optical properties. Differential scanning calorimetry and polarized optical microscopy were employed. The matrix polymer was a one-component UV-curable epoxy-acrylate resin. PDLCs were formed through entropy controlled phase separation resulting from UV-initiated crosslinking. The liquid crystals, both as mesogenic moieties and as dispersed droplets, exhibited various textures according to their molecular order and orientation. These textures formed in constrained regions separated by phase boundaries that occurred at temperatures characteristic of each liquid crystal used. The PDLC phase transitions occurred at temperatures lower than those exhibited by the mesogenic components in the neat state.

scholarly journals Colloidal Lyotropic Liquid Crystalline Phases of Two-Dimensional Nanoparticles of Layered Hybrid Organic-Inorganic Metal Halide Perovskites

2021 ◽  
Author(s):  
PEI-XI WANG
Keyword(s):  
Liquid Crystals ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Metal Halide ◽  
Lyotropic Liquid Crystals ◽  
Two Dimensional ◽  
Halide Anion ◽  
Crystalline Phases ◽  
Liquid Crystalline Phases ◽  
Halide Perovskites

Lyotropic liquid crystals are fluids with macroscopic anisotropic structures formed by the self-assembly of nonspherically-symmetric mesogenic molecules or nanoparticles. Here, lyotropic liquid crystalline phases with discotic-nematic orderings were observed in colloidal dispersions of hexagonal-shaped nanoplatelets of two-dimensional layered hybrid organic-inorganic metal halide perovskites (with formula A<sub>2</sub>BX<sub>4</sub> where A<sup>1+</sup> is an organic ammonium cation, B<sup>2+</sup> is a divalent metal cation, and X<sup>1-</sup> is a halide anion) synthesized via microcrystallization by mixing precursor solutions with antisolvents containing surfactants, which showed semiconducting properties such as blue to green photoluminescence. As nanocrystalline perovskites are compositionally (transition metals like manganese, copper or europium as octahedral unit centers, mixed halides, organic spacers with chirality, etc.), microscopic structurally (three-, two-, or one-dimensional), and geometrically (nanosheets or nanorods) adjustable, liquid crystals with different phase behaviors and physical features (e.g., paramagnetism) may be systematically developed using this method.<br>

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