5,318 results on '"liquid crystals"'
Search Results
2. Fast tunable metamaterial liquid crystal achromatic waveplate
- Author
-
Majd Abu Aisheh, Mohammad Abutoama, Marwan J. Abuleil, and Ibrahim Abdulhalim
- Subjects
Liquid crystals ,Metamaterials ,Tunable achromatic waveplates ,Electrical and Electronic Engineering ,Nanograting ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Biotechnology - Abstract
Photonic metamaterials combined with liquid crystals (LCs) for tunability is a great niche for building miniature devices with high performance such as fast flat tunable lenses, tunable filters, and waveplates. Sub-wavelength or nano-grating surfaces are homogenized to uniaxial waveplates with negative birefringence of unique dispersion when the period is less than the wavelength by at least a few times. This uniaxial metasurface, combined with the LC layer, is shown to act as a tunable retardation achromatic waveplate with 8 μm thick LC layer operating over wide spectral and angular ranges, as compared to using two nematic liquid crystal (NLC) retarders of thicknesses on the order of 30–60 μm, when no metasurface is used. Hence the device becomes miniature and 50× faster due to the thinner liquid crystal layer. The silicon nano-grating of 351 nm pitch and 0.282 fill factor is designed and fabricated to operate in the short-wave infrared range (SWIR). Switching between three achromatic retardation levels: full-, half-, and quarter-waveplates is accomplished by changing the applied voltages on the NLC cell with a switching time of a few milliseconds. This device has applications in fast broadband shutters, low coherence phase shift interferometry, ellipso-polarimetry, dynamic control of light intensity, and smart windows.
- Published
- 2023
3. Structure-rheology relationship in monoolein liquid crystals
- Author
-
Shweta Mistry, Philipp L. Fuhrmann, Auke de Vries, Raffi Karshafian, and Dérick Rousseau
- Subjects
Biomaterials ,Colloid and Surface Chemistry ,X-Ray Diffraction ,Scattering, Small Angle ,Rheology ,Liquid Crystals ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
Monoolein liquid crystals find use in foods and pharmaceuticals. Our hypotheses were: (a) liquid crystal symmetry dominates yielding and large deformation, and (b) strain rate frequency superposition (SRFS) may be used to determine mesophase long and short relaxation times.Liquid crystal microstructure and rheology were characterised as a function of temperature and composition. Their structure was assessed using small angle X-ray scattering (SAXS) and polarised light microscopy. Small and large deformation rheology was characterised using frequency and amplitude sweeps, large amplitude oscillatory shear tests, and SRFS.We have contributed to the structure-rheology relationship governing the properties of the lamellar, cubic, and hexagonal mesophases. Initially, we characterised a number of monoolein-water binary phase transitions, which showed similar behaviour with earlier efforts. Frequency sweeps revealed that the cubic phases had the highest elasticity followed by the lamellar and hexagonal phases. The stiffening and thickening ratios, extracted from the Lissajous-Bowditch plots, were used to quantify intra-cycle non-linearities. The cubic phases displayed abrupt yielding with more pronounced stiffening and thinning behaviour compared to the others. Each liquid crystal phase displayed unique rheological behaviour upon large deformation and, by linking rheology with SAXS and composition, we show that their symmetry defined their rheology.
- Published
- 2023
4. Bringing lipidic lyotropic liquid crystal technology into biomedicine
- Author
-
Guillermo Blanco-Fernandez, Barbara Blanco-Fernandez, Anxo Fernández-Ferreiro, and Francisco Otero-Espinar
- Subjects
Pharmacology ,Technology ,Humans ,Toxicology ,Liquid Crystals - Abstract
Liquid crystals (LCs), discovered more than 130 years ago, are now emerging in the field of biomedicine. This article highlights the recent uses of lipid lyotropic LCs in therapeutics delivery, imaging, and tissue engineering and invites the scientific community to continue exploring the design of more complex LCs.
- Published
- 2023
5. Development of liquid crystal displays and related improvements to their performances
- Author
-
Shunsuke KOBAYASHI, Tomohiro MIYAMA, Hidenari AKIYAMA, Atsushi IKEMURA, and Michio KITAMURA
- Subjects
Data Display ,General Physics and Astronomy ,General Medicine ,General Agricultural and Biological Sciences ,Liquid Crystals - Abstract
This review article comprises three contents: 1) a general introduction of liquid crystals (LCs) and their chronological developments until their current status, 2) the descriptions of the achievements of defect-free and optically high-quality LC displays (LCDs), and 3) the description of the new and alternative methods for improving existing LCD technologies in terms of high-speed response, viewing angles, and power consumption through nanoparticle doping and optical compensation on a laboratory level. When these technologies are successfully developed, they will be used in the industry, where the fabrication process will be performed in a large-clean room using automated robotics.
- Published
- 2022
6. The influence of entropic crowding in cell monolayers
- Author
-
Alberto Ippolito and Vikram S. Deshpande
- Subjects
Entropy ,Biophysics ,Thermodynamics ,Liquid Crystals - Abstract
Cell-cell interaction dictates cell morphology and organization, which play a crucial role in the micro-architecture of tissues that guides their biological and mechanical functioning. Here, we investigate the effect of cell density on the responses of cells seeded on flat substrates using a novel statistical thermodynamics framework. The framework recognizes the existence of nonthermal fluctuations in cellular response and thereby naturally captures entropic interactions between cells in monolayers. In line with observations, the model predicts that cell area and elongation decrease with increasing cell seeding density-both are a direct outcome of the fluctuating nature of the cellular response that gives rise to enhanced cell-cell interactions with increasing cell crowding. The modeling framework also predicts the increase in cell alignment with increasing cell density: this cellular ordering is also due to enhanced entropic interactions and is akin to nematic ordering in liquid crystals. Our simulations provide physical insights that suggest that entropic cell-cell interactions play a crucial role in governing the responses of cell monolayers.
- Published
- 2022
7. Light-Responsive Molecular Release from Cubosomes Using Swell-Squeeze Lattice Control
- Author
-
Beatrice E. Jones, Elaine A. Kelly, Nathan Cowieson, Giorgio Divitini, Rachel C. Evans, Divitini, Giorgio [0000-0003-2775-610X], Evans, Rachel C [0000-0003-2956-4857], and Apollo - University of Cambridge Repository
- Subjects
Colloid and Surface Chemistry ,Water ,General Chemistry ,Stimuli Responsive Polymers ,Azo Compounds ,Biochemistry ,Article ,Catalysis ,Liquid Crystals - Abstract
Stimuli-responsive materials are crucial to advance controlled delivery systems for drugs and catalysts. Lyotropic liquid crystals (LLCs) have well-defined internal structures suitable to entrap small molecules and can be broken up into low-viscosity dispersions, aiding their application as delivery systems. In this work, we demonstrate the first example of light-responsive cubic LLC dispersions, or cubosomes, using photoswitchable amphiphiles to enable external control over the LLC structure and subsequent on-demand release of entrapped guest molecules. Azobenzene photosurfactants (AzoPS), containing a neutral tetraethylene glycol head group and azobenzene-alkyl tail, are combined (from 10-30 wt %) into monoolein-water systems to create LLC phases. Homogenization of the bulk LLC forms dispersions of particles, ∼200 nm in diameter with internal bicontinuous primitive cubic phases, as seen using small-angle X-ray scattering and cryo-transmission electron microscopy. Notably, increasing the AzoPS concentration leads to swelling of the cubic lattice, offering a method to tune the internal nanoscale structure. Upon UV irradiation, AzoPS within the cubosomes isomerizes within seconds, which in turn leads to squeezing of the cubic lattice and a decrease in the lattice parameter. This squeeze mechanism was successfully harnessed to enable phototriggerable release of trapped Nile Red guest molecules from the cubosome structure in minutes. The ability to control the internal structure of LLC dispersions using light, and the dramatic effect this has on the retention of entrapped molecules, suggests that these systems may have huge potential for the next-generation of nanodelivery.
- Published
- 2022
8. Spontaneous Polarization Characteristics in Polar Smectic Phases of Fluoro-Substituted Bent-Shaped Dimeric Molecules
- Author
-
Nakasugi, Shigemasa, Kang, Sungmin, Chang, Tso-Fu Mark, Manaka, Takaaki, Ishizaki, Hiroki, Sone, Masato, and watanabe, junji
- Subjects
Polymers ,Temperature ,Materials Chemistry ,Fluorine ,Physical and Theoretical Chemistry ,Electrodes ,Liquid Crystals ,Surfaces, Coatings and Films - Abstract
Three kinds of bent-shaped dimeric molecules are synthesized by fluorine substitution of C16 molecules, and influences of the substitution on the polar smectic phases are examined. The fluorine-substituted C16 molecules form the SmAP
- Published
- 2022
9. Molecular Shape and Polar Order in Columnar Liquid Crystals
- Author
-
Timothy M. Swager
- Subjects
Alkanes ,Temperature ,Thermodynamics ,General Medicine ,General Chemistry ,Plastics ,Liquid Crystals - Abstract
ConspectusBottom-up materials design by the conceiving of new molecular building blocks is powerful and chemists are uniquely qualified to innovate. Liquid crystals (LCs) and related soft crystals, collectively called mesophases, naturally create materials with dynamic properties. The thermotropic LC state has a liquid-like intermolecular disorder, but the cooperative nature of these materials facilitates a long-range directional order (alignment) that couples strongly to applied electric/magnetic fields and interfaces. Thermotropic LCs are held together by mesogen cores, which are often unsaturated with anisotropic polarizability, and are appended with flexible (often
- Published
- 2022
10. Nematic-like elastic coefficients of the SmAb phase
- Author
-
Claire Meyer, Patrick Davidson, Tatiana Sergan, Vassili Sergan, Daniel Stoenescu, Anamarija Knežević, Irena Dokli, Andreja Lesac, and Ivan Dozov
- Subjects
liquid crystals ,nematic ,smectic ,elastic constants ,defects ,General Materials Science ,General Chemistry ,Condensed Matter Physics - Abstract
The synthesis of bent-shaped mesogens and mesogenic dimers has renewed the field of liquid crystals in many ways during the previous decades, for example, through the discovery of ‘exotic’ mesophases such as the twist-bend nematic phase and the biaxial SmA phase (SmAb). Recently, we reported on the observation of a SmAb with a bent- shaped dimer, and on its fast electro-optic effect that we interpreted as a biaxial Fréedericksz transition (BFrTr) of the secondary m-director under applied electric field (C. Meyer et al., Phys. Rev. X, 11, 031012 (2021)). In this study, we used dielectric and birefringence techniques to directly measure the splay, Km11, and bend, Km33, elastic constants that characterise the elastic distortion modes of the m-director. We observed that during the BFrTr, domains of opposite tilt appear and are often enclosed in elliptical defect loops, just like those observed during the usual Fréedericksz transition of common nematics, which allowed us to obtain the third (twist) elastic constant Km22, from the defect loop ellipticity. Although Km11 and Km33 are of the same order of magnitude as K11 and K33 in the nematic phase of bent-shaped dimers, Km22 is an order of magnitude smaller than Km11 and Km33 and also than K22 of 5CB. We argue that these features could be generic for the intercalated SmAb phase of bent-shaped dimers.
- Published
- 2022
11. Ordering Transitions of Liquid Crystals Triggered by Metal Oxide-catalyzed Reactions of Sulfur Oxide Species
- Author
-
Nanqi Bao, Jake I. Gold, Jonathan K. Sheavly, James J. Schauer, Victor M. Zavala, Reid C. Van Lehn, Manos Mavrikakis, and Nicholas L. Abbott
- Subjects
Titanium ,Colloid and Surface Chemistry ,Biphenyl Compounds ,Nitriles ,Carboxylic Acids ,Sulfur Oxides ,General Chemistry ,Biochemistry ,Catalysis ,Liquid Crystals - Abstract
Liquid crystals (LCs), when supported on reactive surfaces, undergo changes in ordering that can propagate over distances of micrometers, thus providing a general and facile mechanism to amplify atomic-scale transformations on surfaces into the optical scale. While reactions on organic and metal substrates have been coupled to LC-ordering transitions, metal oxide substrates, which offer unique catalytic activities for reactions involving atmospherically important chemical species such as oxidized sulfur species, have not been explored. Here, we investigate this opportunity by designing LCs that contain 4'-cyanobiphenyl-4-carboxylic acid (CBCA) and respond to surface reactions triggered by parts-per-billion concentrations of SO
- Published
- 2022
12. Designing Biological Microsensors with Chiral Nematic Liquid Crystal Droplets
- Author
-
Lawrence W. Honaker, Chang Chen, Floris M.H. Dautzenberg, Sylvia Brugman, and Siddharth Deshpande
- Subjects
Surface-Active Agents ,WIAS ,Life Science ,Animals ,General Materials Science ,Adsorption ,Host-Microbe Interactomics ,Physical Chemistry and Soft Matter ,Zebrafish ,Liquid Crystals ,VLAG - Abstract
Biosensing using liquid crystals has a tremendous potential by coupling the high degree of sensitivity of their alignment to their surroundings with clear optical feedback. Many existing set-ups use birefringence of nematic liquid crystals, which severely limits straightforward and frugal implementation into a sensing platform due to the sophisticated optical set-ups required. In this work, we instead utilize chiral nematic liquid crystal microdroplets, which show strongly reflected structural color, as sensing platforms for surface active agents. We systematically quantify the optical response of closely related biological amphiphiles and find unique optical signatures for each species. We detect signatures across a wide range of concentrations (from micromolar to millimolar), with fast response times (from seconds to minutes). The striking optical response is a function of the adsorption of surfactants in a nonhomogeneous manner and the topology of the chiral nematic liquid crystal orientation at the interface requiring a scattering, multidomain structure. We show that the surface interactions, in particular, the surface packing density, to be a function of both headgroup and tail and thus unique to each surfactant species. We show lab-on-a-chip capability of our method by drying droplets in high-density two-dimensional arrays and simply hydrating the chip to detect dissolved analytes. Finally, we show proof-of-principle in vivo biosensing in the healthy as well as inflamed intestinal tracts of live zebrafish larvae, demonstrating CLC droplets show a clear optical response specifically when exposed to the gut environment rich in amphiphiles. Our unique approach shows clear potential in developing on-site detection platforms and detecting biological amphiphiles in living organisms.
- Published
- 2022
13. The Phonon Theory of Liquids and Biological Fluids: Developments and Applications
- Author
-
Dima Bolmatov
- Subjects
Diffusion ,Solutions ,Phonons ,Thermodynamics ,General Materials Science ,Physical and Theoretical Chemistry ,Liquid Crystals - Abstract
Among the three basic states of matter (solid, liquid, and gas), the liquid state has always eluded general theoretical approaches for describing liquid energy and heat capacity. In this Viewpoint, we derive the phonon theory of liquids and biological fluids stemming from Frenkel's microscopic picture of the liquid state. Specifically, the theory predicts the existence of phonon gaps in vibrational spectra of liquids and a thermodynamic boundary in the supercritical state. Direct experimental evidence reaffirming these theoretical predictions was achieved through a combination of techniques using static compression X-ray diffraction and inelastic X-ray scattering on deeply supercritical argon in a diamond anvil cell. Furthermore, these findings inspired and then led to the discovery of phonon gaps in liquid crystals (mesogens), block copolymers, and biological membranes. Importantly, phonon gaps define viscoelastic crossovers in cellular membranes responsible for lipid self-diffusion, lateral molecular-level stress propagation, and passive transmembrane transport of small molecules and solutes. Finally, molecular interactions mediated by external stimuli result in synaptic activity controlling biological membranes' plasticity resulting in learning and memory. Therefore, we also discuss learning and memory effects─equally important for neuroscience as well as for the development of neuromorphic devices─facilitated in biological membranes by external stimuli.
- Published
- 2022
14. Recent advances in versatile inverse lyotropic liquid crystals
- Author
-
Xinyu, Shan, Lihua, Luo, Zhixin, Yu, and Jian, You
- Subjects
Drug Delivery Systems ,Nanoparticles ,Pharmaceutical Science ,Liquid Crystals - Abstract
Owing to the rapid and significant progress in advanced materials and life sciences, nanotechnology is increasingly gaining in popularity. Among numerous bio-mimicking carriers, inverse lyotropic liquid crystals are known for their unique properties. These carriers make accommodation of molecules with varied characteristics achievable due to their complicated topologies. Besides, versatile symmetries of inverse LCNPs (lyotropic crystalline nanoparticles) and their aggregating bulk phases allow them to be applied in a wide range of fields including drug delivery, food, cosmetics, material sciences etc. In this review, in-depth summary, discussion and outlook for inverse lyotropic liquid crystals are provided.
- Published
- 2022
15. Light-Responsive Springs from Electropatterned Liquid Crystal Polymer Networks
- Author
-
Alexander Ryabchun, Federico Lancia, and Nathalie Katsonis
- Subjects
soft robotics ,liquid crystals ,artificial molecular switches ,liquid crystal networks ,chirality ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Abstract
Future robotic systems will have to adapt their operation to dynamic environments and therefore their development will require the use of active soft components. Bioinspired approaches toward novel actuation materials for active components rely on integrating molecular machines in soft matter, and ensuring that their nanoscale movement is amplified to the macroscale, where mechanically relevant motion is generated. This approach is successfully used in the design of photoresponsive soft springs and other mechanically active materials. Here, this study reports on a new approach where the operation of photoswitches and chiral liquid crystals are combined with an original and mask-free microscopic patterning method to generate helix-based movement at the macroscale, including light-driven winding and unwinding accompanied with inversion of handedness. The microscopic patterning is the result of the unique organization of cholesteric liquid crystals under weak electric field. At a higher level, the pitch and the handedness of the active springs are defined by the imprinted pattern and the angle at which the spring ribbons are cut in the material. These findings are likely to enable soft and responsive robotic systems, and they show how transmission of molecular operation into macroscale functional movement is enabled by materials design across multiple hierarchical levels.
- Published
- 2023
16. Collective Relaxation Processes in Nonchiral Nematics
- Author
-
Vij, Neelam Yadav, Yuri P. Panarin, Wanhe Jiang, Georg H. Mehl, and Jagdish K.
- Subjects
dielectric spectroscopy ,dielectric permittivity ,ferroelectric nematics ,chiral ,relaxation processes ,planar alignment ,nematic–nematic transitions ,liquid crystals - Abstract
Nematic–nematic transitions in a highly polar nematic compound are studied, in thick cells in which the molecules are aligned parallel to the substrates but perpendicular to the applied electric field, using dielectric spectroscopy in the frequency range 1 Hz to 10 MHz over a wide temperature range. The studied compound displays three nematic phases under cooling from the isotropic phase: ubiquitous nematic N; high polarizability NX; and ferroelectric nematic NF. Two collective processes were observed. The dielectric strength and relaxation frequency of one of the processes P2 showed a dependence on the thickness of the cell. The process P1 is the amplitude mode, while the process P2 is the phason mode.
- Published
- 2023
- Full Text
- View/download PDF
17. Editorial: Active and Intelligent Living Matter: from Fundamentals to Applications
- Author
-
Doostmohammadi, Amin, Mazza, Marco G., Shendruk, Tyler N., and Stark, Holger
- Subjects
soft matter ,liquid crystals ,Materials Science (miscellaneous) ,500 Naturwissenschaften und Mathematik::530 Physik::530 Physik ,self-organisation ,active matter physics ,Biophysics ,General Physics and Astronomy ,amoeba ,Physical and Theoretical Chemistry ,bacteria ,Mathematical Physics - Published
- 2023
- Full Text
- View/download PDF
18. Physical and Thermal Characterizations of Newly Synthesized Liquid Crystals Based on Benzotrifluoride Moiety
- Author
-
Al-Kadhi, Fowzia S. Alamro, Hoda A. Ahmed, Mohamed A. El-Atawy, Muna S. Khushaim, Noha S. Bedowr, Rawan AL-Faze, and Nada S.
- Subjects
liquid crystals ,benzotrifluoride ,physical characterizations ,DFT ,dimorphic - Abstract
The mesomorphic stability and optical activity of new group-based benzotrifluoride liquid crystals, (E)-4-(((4-(trifluoromethyl) phenyl) imino) methyl) phenyl 4-(alkyloxy)benzoate, or In, were investigated. The end of the molecules connected to the benzotrifluoride moiety and the end of the phenylazo benzoate moiety have terminal alkoxy groups which can range in chain length from 6 to 12 carbons. The synthesized compounds’ molecular structures were verified using FT-IR, 1H NMR, mass spectroscopy, and elemental analysis. Mesomorphic characteristics were verified using differential scanning calorimetry (DSC) and a polarized optical microscope (POM). All of the homologous series that have been developed display great thermal stability across a broad temperature range. Density functional theory (DFT) determined the examined compounds’ geometrical and thermal properties. The findings showed that every compound is entirely planar. Additionally, by using the DFT approach, it was possible to link the experimentally found values of the investigated compounds’ investigated compounds’ mesophase thermal stability, mesophase temperature ranges, and mesophase type to the predicted quantum chemical parameters.
- Published
- 2023
- Full Text
- View/download PDF
19. Boundary and size effects in chromonic liquid crystal emulsions
- Author
-
Vergés Vilarrubia, Marc, Ignés i Mullol, Jordi, Sagués i Mestre, Francesc, and Herrera Restrepo, Ramón S.
- Subjects
Liquid crystals ,Microfluidics ,Bachelor's theses ,Cristalls líquids ,Emulsions ,Treballs de fi de grau ,Microfluídica - Abstract
Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2023, Tutors: Jordi Ignés Mullol, Francesc Sagués Mestre, Ramon Santiago Herrera Restrepo, Liquid crystals (LCs) are unique states of matter that exhibit both liquid and crystal properties. From the 19th century until now, extensive research has been carried out to understand and take advantage of the fascinating properties of liquid crystals. An intriguing subclass of liquid crystals is the lyotropic chromonic liquid crystal (LCLC). Unlike thermotropic liquid crystals as 5CB, which form through temperature changes, LCLCs are formed when certain organic molecules, known as chromonic dyes, are dissolved in solvents such as water. These LCLCs exhibit a rich variety of phase behavior and unique optical properties, making them of great interest to various applications, including screens, sensors, and biomedical devices. One of the most famous LCLC is Sunset Yellow (SSY). To Describe the confinement of 5CB and SSY and observe phenomena such as the boundary effects in emulsified droplets will be one of the aims of our work. In order to form the emulsions, microfluidic systems will be used. They use small channels and precise control of fluid flows to create well-defined structures and patterns of liquid crystals. This approach offers several advantages, such as high performance, precise control of the size and shape of droplets, and the ability to create complex geometries. Once the emulsions are generated, we will study the properties of confined LCs in droplets and their behavior in front of an external magnetic field.
- Published
- 2023
20. Reconfiguration of Nematic Disclinations in Plane-Parallel Confinements
- Author
-
Kralj, Saša Harkai, Charles Rosenblatt, and Samo
- Subjects
liquid crystals ,topological defects ,disclinations ,reconfiguration - Abstract
We study numerically the reconfiguration process of colliding m=1/2 strength disclinations in an achiral nematic liquid crystal (NLC). A Landau–de Gennes approach in terms of tensor nematic-order parameters is used. Initially, different pairs m1,m2 of parallel wedge disclination lines connecting opposite substrates confining the NLC in a plane-parallel cell of a thickness h are imposed: {1/2,1/2}, {−1/2,−1/2} and {−1/2,1/2}. The collisions are imposed by the relative rotation of the azimuthal angle θ of the substrates that strongly pin the defect end points. Pairs {1/2,1/2} and {−1/2,−1/2} “rewire” at the critical angle θc1=3π4 in all cases studied. On the other hand, two qualitatively different scenarios are observed for {−1/2,1/2}. In the thinner film regime hhc, the colliding disclinations at θc2 reconfigure into boojum-like twist disclinations.
- Published
- 2023
- Full Text
- View/download PDF
21. Indium Recycling from Waste Liquid Crystal Displays: Is It Possible?
- Author
-
Aleksandra Anić Vučinić, Snježana Šimunić, Lucija Radetić, and Ivana Presečki
- Subjects
Process Chemistry and Technology ,waste electric and electronic equipment (WEEE) ,liquid crystal displays (LCDs) ,liquid crystals ,indium recovery ,recycling ,Chemical Engineering (miscellaneous) ,Bioengineering - Abstract
The utilization of valuable properties of waste and their reuse as raw materials is an imperative of the circular economy. Waste electrical and electronic equipment (WEEE) is a significant source of valuable raw materials, certain metals, and rare earth elements that are the basis for highly sophisticated IT equipment production. It is estimated that the production of WEEE in Europe in 2019 was 16.20 kg/inhabitant, while quantities continue to grow at a rate of 3–4% per year. Waste liquid crystal displays used in televisions, laptops, desktops, and other devices represent a significant share of WEEE and contain 0.12–0.14% of liquid crystals whose main ingredient is indium—tin oxide. In order to investigate and determine the methods and conditions of indium recycling from waste LCDs, laboratory research was conducted. The influence of temperature, particle size, and retention time in different media with and without ultrasound treatment was monitored to provide the efficiency of indium leaching. The analysis of the results showed that 98% indium leaching was achieved with granulation samples of 10 × 10 mm at a temperature 40 °C/40 min in solution H2O:HCl: HNO3 = 6:2:1 under ultrasound conditions, while aqueous and alkaline media under the same conditions did not show significant efficiency. This study can be used as a practical reference for the recycling of indium from LCD panels.
- Published
- 2023
- Full Text
- View/download PDF
22. Elongated Bacterial Pili as a Versatile Alignment Medium for NMR Spectroscopy
- Author
-
Sirine Nouri, Julien Boudet, Hiang Dreher-Teo, Frédéric H.-T. Allain, Rudi Glockshuber, Loïc Salmon, and Christoph Giese
- Subjects
Residual Dipolar Couplings ,Alignment Medium ,General Medicine ,General Chemistry ,NMR Spectroscopy ,Liquid Crystals ,Type 1 Pili ,Catalysis - Abstract
In NMR spectroscopy, residual dipolar couplings (RDCs) have emerged as one of the most exquisite probes of biological structure and dynamics. The measurement of RDCs relies on the partial alignment of the molecule of interest, for example by using a liquid crystal as a solvent. Here, we establish bacterial type 1 pili as an alternative liquid-crystalline alignment medium for the measurement of RDCs. To achieve alignment at pilus concentrations that allow for efficient NMR sample preparation, we elongated wild-type pili by recombinant overproduction of the main structural pilus subunit. Building on the extraordinary stability of type 1 pili against spontaneous dissociation and unfolding, we show that the medium is compatible with challenging experimental conditions such as high temperature, the presence of detergents, organic solvents or very acidic pH, setting it apart from most established alignment media. Using human ubiquitin, HIV-1 TAR RNA and camphor as spectroscopic probes, we demonstrate the applicability of the medium for the determination of RDCs of proteins, nucleic acids and small molecules. Our results show that type 1 pili represent a very useful alternative to existing alignment media and may readily assist the characterization of molecular structure and dynamics by NMR., Angewandte Chemie. International Edition, ISSN:1433-7851, ISSN:1521-3773, ISSN:0570-0833
- Published
- 2023
23. Columnar Liquid Crystals of Copper(I) Complexes with Ionic Conductivity and Solid State Emission
- Author
-
Viorel Cîrcu, Constantin P. Ganea, Mihail Secu, Doina Manaila-Maximean, George Cătălin Marinescu, Roua Gabriela Popescu, and Iuliana Pasuk
- Subjects
Chemistry (miscellaneous) ,Organic Chemistry ,Drug Discovery ,Molecular Medicine ,Pharmaceutical Science ,liquid crystals ,copper(I) ,luminescence ,columnar phase ,ionic conductivity ,dielectric spectroscopy ,benzoylthiourea ,Physical and Theoretical Chemistry ,Analytical Chemistry - Abstract
Two neutral copper(I) halide complexes ([Cu(BTU)2X], X = Cl, Br) were prepared by the reduction of the corresponding copper(II) halides (chloride or bromide) with a benzoylthiourea (BTU, N-(3,4-diheptyloxybenzoyl)-N′-(4-heptadecafluorooctylphenyl)thiourea) ligand in ethanol. The two copper(I) complexes show a very interesting combination of 2D supramolecular structures, liquid crystalline, emission, and 1D ionic conduction properties. Their chemical structure was ascribed based on ESI–MS, elemental analysis, IR, and NMR spectroscopies (1H and 13C), while the mesomorphic behavior was analyzed through a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These new copper(I) complexes have mesomorphic properties and exhibit a hexagonal columnar mesophase over a large temperature range, more than 100 K, as evidenced by DSC studies and POM observations. The thermogravimetric analysis (TG) indicated a very good thermal stability of these samples up to the isotropization temperatures and over the whole temperature range of the liquid crystalline phase existence. Both complexes displayed a solid-state emission with quantum yields up to 8% at ambient temperature. The electrical properties of the new metallomesogens were investigated by variable temperature dielectric spectroscopy over the entire temperature range of the liquid crystalline phase. It was found that the liquid crystal phases favoured anhydrous proton conduction provided by the hydrogen-bonding networks formed by the NH…X moieties (X = halide or oxygen) of the benzoylthiourea ligand in the copper(I) complexes. A proton conductivity of 2.97 × 10−7 S·cm−1 was achieved at 430 K for the chloro-complex and 1.37 × 10−6 S·cm−1 at 440K for the related bromo-complex.
- Published
- 2023
- Full Text
- View/download PDF
24. Preparation of Laterally Chloro-Substituted Schiff Base Ester Liquid Crystals: Mesomorphic and Optical Properties
- Author
-
Violeta Jevtovic, Hoda A. Ahmed, Mohd Taukeer Khan, Salma A. Al-Zahrani, Najat Masood, and Yassin Aweis Jeilani
- Subjects
Inorganic Chemistry ,General Chemical Engineering ,General Materials Science ,Condensed Matter Physics ,lateral chlorine ,liquid crystals ,mesophase stability ,optical properties ,thin film ,energy bandgap - Abstract
A new class of Schiff base/ester compounds: ICln, 4-((2′-chlorophenylimino)methyl)phenyl-4″-alkoxy benzoates, were synthesized and their mesophase characteristics and thermal behavior were evaluated. Differential scanning calorimetry (DSC) was used to study mesophase transitions, and polarized optical microscopy was carried out to identify the phases (POM). The results show that all compounds are monomorphic, and enantiotropic nematic (N) phases were seen at all side chains. It was found that lateral Cl atoms in the terminal benzene ring influence both conformation and mesomorphic properties. Comparisons between the present investigated lateral Cl derivatives and their laterally neat, as well as their isomeric, compounds have been briefly discussed. Results revealed that the insertion of lateral Cl substituent in the molecular structure impacts the type and stability of the formed mesophases. The exchanges of the ester-connecting moiety improve their thermal nematic stability than their previously prepared structurally isomeric derivatives. These compounds exhibit a broad absorption in the UV-Visible region, including a peak in UV region and a tail around 550 nm, and there were observed to be absorption tail increases and energy band gap decreases with the increase of the alkoxy side chain length. The photoluminescence (PL) intensity was noted to be quenched for the bulky alkoxy group ascribed to non-radiative recombination through the defect states. Moreover, time resolved fluorescence decay spectra reveal that both the radiative and non-radiative recombination lifetime increases with the increase of alkoxy side chain length.
- Published
- 2023
- Full Text
- View/download PDF
25. Nanocalorimetry using microscopic optical wireless integrated circuits
- Author
-
Conrad L. Smart, Alejandro J. Cortese, B. J. Ramshaw, and Paul L. McEuen
- Subjects
Multidisciplinary ,Temperature ,Thermodynamics ,Thermal Conductivity ,Calorimetry ,Liquid Crystals - Abstract
We present in situ calorimetry, thermal conductivity, and thermal diffusivity measurements of materials using temperature-sensing optical wireless integrated circuits (OWiCs). These microscopic and untethered optical sensors eliminate input wires and reduce parasitic effects. Each OWiC has a mass of ∼100 ng, a 100-μm-scale footprint, and a thermal response time of microseconds. We demonstrate that they can measure the thermal properties of nearly any material, from aerogels to metals, on samples as small as 100 ng and over thermal diffusivities covering four orders of magnitude. They also function over a broad temperature range, and we present proof-of-concept measurements of the thermodynamic phase transitions in both liquid crystal 5CB and gadolinium.
- Published
- 2023
26. Nematic bits and universal logic gates
- Author
-
Jörn Dunkel and Žiga Kos
- Subjects
nematic bits ,logična vrata ,tekoči kristali ,Multidisciplinary ,liquid crystals ,udc:538.9 ,logic gates ,Condensed Matter - Soft Condensed Matter ,nematski biti - Abstract
Liquid crystals (LCs) can host robust topological defect structures that essentially determine their optical and elastic properties. Although recent experimental progress enables precise control over localization and dynamics of nematic LC defects, their practical potential for information storage and processing has yet to be explored. Here, we introduce the concept of nematic bits (nbits) by exploiting a quaternionic mapping from LC defects to the Poincar\'e-Bloch sphere. Through theory and simulations, we demonstrate how single-nbit operations can be implemented using electric fields, in close analogy with Pauli, Hadamard and other common quantum gates. Ensembles of two-nbit states can exhibit strong statistical correlations arising from nematoelastic interactions, which can be used as a computational resource. Utilizing nematoelastic interactions, we show how suitably arranged 4-nbit configurations can realize universal classical NOR and NAND gates. Finally, we demonstrate the implementation of generalized logical functions that take values on the Poincar\'e-Bloch sphere. These results open a new route towards the implementation of classical and non-classical computation strategies in topological soft matter systems., Comment: title updated; introduction extended; nbit realizations of universal NAND and NOR gates and generalized logic functions added in new Figures 6 and 7
- Published
- 2023
27. Luminescent liquid crystals: from supramolecular plant dyes to emissive flavylium salts
- Author
-
Robert Forschner, Julius Agamemnon Knöller, Anna Zens, Wolfgang Frey, Yann Molard, Sabine Laschat, Universität Stuttgart [Stuttgart], Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bundesministerium fuer Bildung und Forschung [01 R1 05177], Deutsche Forschungsgemeinschaft [La 907/17-2, La 907/20-1], German Academic Exchange Service [PHC Procope], Ministerium fuer Wissenschaft, Forschung und Kunst Baden-Wuerttemberg, Carl-Schneider-Stiftung, and Studienstiftung des Deutschen Volkes
- Subjects
Xray ,liquid crystals ,[CHIM]Chemical Sciences ,General Materials Science ,General Chemistry ,ionic liquid crystals ,Condensed Matter Physics ,Flavylium salts - Abstract
Accepted manuscript / Clean copy; International audience; Inspired by the supramolecular architecture of cornflower blue we developed luminescent flavylium salts with lipophilic alkoxy or thioether side chains which self-assemble into liquid crystalline phases. The current account highlights some fundamental aspects of our biological 'role model' anthocyanine, the origin of the natural pigment cornflower blue, and our recent developments on novel liquid crystalline emissive dyes. Starting with the general synthesis of flavylium salts, other topics address variations of flavylium ILCs, including specific tuning of their mesomorphic and photophysical behaviour.
- Published
- 2023
28. Curvature-mediated Programming of Liquid Crystal Microflows
- Author
-
Fedorowicz, Kamil, Prosser, Sengupta, Anupam, and Fonds National de la Recherche - FnR [sponsor]
- Subjects
liquid crystals ,Physique [G04] [Physique, chimie, mathématiques & sciences de la terre] ,curvature ,microfluidics ,Physics [G04] [Physical, chemical, mathematical & earth Sciences] ,Fluid Dynamics (physics.flu-dyn) ,Soft Condensed Matter (cond-mat.soft) ,FOS: Physical sciences ,Applied Physics (physics.app-ph) ,Physics - Applied Physics ,Physics - Fluid Dynamics ,Condensed Matter - Soft Condensed Matter - Abstract
Using experiments and numerical simulations, we demonstrate that the curvature of microscale conduits allow programming of liquid crystal (LC) flows. Focusing on a nematic LC flowing through U- and L-shaped channels of rectangular cross-section, our results reveal that curved flow paths can trigger gradients of flow-induced director field in the transverse direction. The emergent director field feeds back into the flow field, ultimately leading to LC flows controlled by the channel curvature. This curvature-mediated flow control, identified by polarizing optical microscopy and supported by the nematofluidic solutions, offers novel concepts in LC-based microfluidic valves and throttles, wherein the throughput distribution is determined by the Ericksen number and the variations in the local curvature. Finally, this work highlights the role of deformation history on flow-induced director alignments, when the viscous and elastic effects comparable in strength., 6 pages, 4 figures
- Published
- 2023
29. Suspect Screening of Liquid Crystal Monomers (LCMs) in Sediment Using an Established Database Covering 1173 LCMs
- Author
-
Huijun Su, Kefan Ren, Rongrong Li, Jianhua Li, Zhanqi Gao, Guanjiu Hu, Pingqing Fu, and Guanyong Su
- Subjects
Arctic Regions ,Environmental Chemistry ,Benzene ,General Chemistry ,Gas Chromatography-Mass Spectrometry ,Liquid Crystals - Abstract
Recent studies have suggested that liquid crystal monomers (LCMs) are emerging contaminants in the environment, and knowledge of this class of substances is very rare. Here, we reviewed existing LCM-related documents, i.e., publications and patents, and established a database involving 1173 LCMs. These 1173 LCMs were further calculated for their physicochemical properties, i.e., persistence (P), bioaccumulation (B), long-range transport potential (LRTP), and Arctic contamination and bioaccumulation potential (ACBAP). We found that 476 out of them were PB chemicals (99% of them were halogenated), and 320 of them could have ACBAP properties (67% of them were halogenated). This LCM database was further applied for suspect screening of LCMs in
- Published
- 2022
30. Dual-Cross-linked Liquid Crystal Hydrogels with Controllable Viscoelasticity for Regulating Cell Behaviors
- Author
-
Shengyue Tang, Kun Liu, Jingsheng Chen, Yizhi Li, Mingxian Liu, Lu Lu, Changren Zhou, and Binghong Luo
- Subjects
Osteogenesis ,Cell Differentiation ,Hydrogels ,Mesenchymal Stem Cells ,General Materials Science ,Liquid Crystals - Abstract
The liquid crystal properties and viscoelasticity of the natural bone extracellular matrix (ECM) play a decisive role in guiding cell behavior, conducting cell signals, and regulating mineralization. Here, we develop a facile approach for preparing a novel polysaccharide hydrogel with liquid crystal properties and viscoelasticity similar to those of natural bone ECM. First, a series of chitin whisker/chitosan (CHW/CS) hydrogels were prepared by chemical cross-linking with genipin, in which CHW can self-assemble to form cholesteric liquid crystals under ultrasonic treatment and CS chains can enter into the gaps between the helical layers of the CHW cholesteric liquid crystal phase to endow morphological stability and good mechanical properties. Subsequently, the obtained chemically cross-linked liquid crystal hydrogels were immersed into the desired concentration of the NaCl solution to form physical cross-linking. Due to the Hofmeister effect, the as-prepared dual-cross-linked liquid crystal hydrogels showed an enhanced modulus, viscoelasticity similar to that of natural ECM with relatively fast stress relaxation behavior, and fold surface morphology. Compared to both CHW/CS hydrogels without liquid crystal properties and CHW/CS liquid crystal hydrogels without further physical cross-linking, the dual-cross-linked CHW/CS liquid crystal hydrogels are more favorable for the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells. This approach could inspire the design of hydrogels mimicking the liquid crystal properties and viscoelasticity of natural bone ECM for bone repair.
- Published
- 2022
31. Phototriggered Complex Motion by Programmable Construction of Light-Driven Molecular Motors in Liquid Crystal Networks
- Author
-
Hou, Jiaxin, Long, Guiying, Zhao, Wei, Zhou, Guofu, Liu, Danqing, Broer, Dirk J., Feringa, Ben L., Chen, Jiawen, Synthetic Organic Chemistry, Basic and Translational Research and Imaging Methodology Development in Groningen (BRIDGE), and Stimuli-responsive Funct. Materials & Dev.
- Subjects
Motion ,Colloid and Surface Chemistry ,Polymers ,Movement ,General Chemistry ,Biochemistry ,Catalysis ,Liquid Crystals - Abstract
Recent developments in artificial molecular machines have enabled precisely controlled molecular motion, which allows several distinct mechanical operations at the nanoscale. However, harnessing and amplifying molecular motion along multiple length scales to induce macroscopic motion are still major challenges and comprise an important next step toward future actuators and soft robotics. The key to addressing this challenge relies on effective integration of synthetic molecular machines in a hierarchically aligned structure so numerous individual molecular motions can be collected in a cooperative way and amplified to higher length scales and eventually lead to macroscopic motion. Here, we report the complex motion of liquid crystal networks embedded with molecular motors triggered by single-wavelength illumination. By design, both racemic and enantiomerically pure molecular motors are programmably integrated into liquid crystal networks with a defined orientation. The motors have multiple functions acting as cross-linkers, actuators, and chiral dopants inside the network. The collective rotary motion of motors resulted in multiple types of motion of the polymeric film, including bending, wavy motion, fast unidirectional movement on surfaces, and synchronized helical motion with different handedness, paving the way for the future design of responsive materials with enhanced complex functions.
- Published
- 2022
32. Effect of Polymer Hydrophobicity in the Performance of Hybrid Gel Gas Sensors for E-Noses
- Author
-
Ana Rita Oliveira, Henrique M. A. Costa, Efthymia Ramou, Susana I. C. J. Palma, Ana Cecília A. Roque, UCIBIO - Applied Molecular Biosciences Unit, and DQ - Departamento de Química
- Subjects
electronic nose ,gas sensing ,ionogels ,humidity ,PDMS ,gelatin ,ionic liquids ,liquid crystals ,Biochemistry ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Electrical and Electronic Engineering ,Instrumentation ,Information Systems - Abstract
Funding Information: This research was funded by the European Research Council (ERC) under the EU Horizon 2020 research and innovation programme [SCENT-ERC-2014-STG-639123, (2015–2022) and Grant Agreement No. 101069405-ENSURE-ERC-2022-POC1] and by national funds from FCT-Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Bio-sciences, UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy and i4HB. The authors thank FCT/MCTES for the PhD grants SFRH/BD/128687/2017 and SFRH/BD/14131/2019. Publisher Copyright: © 2023 by the authors. Relative humidity (RH) is a common interferent in chemical gas sensors, influencing their baselines and sensitivity, which can limit the performance of e-nose systems. Tuning the composition of the sensing materials is a possible strategy to control the impact of RH in gas sensors. Hybrid gel materials used as gas sensors contain self-assembled droplets of ionic liquid and liquid crystal molecules encapsulated in a polymeric matrix. In this work, we assessed the effect of the matrix hydrophobic properties in the performance of hybrid gel materials for VOC sensing in humid conditions (50% RH). We used two different polymers, the hydrophobic PDMS and the hydrophilic bovine gelatin, as polymeric matrices in hybrid gel materials containing imidazolium-based ionic liquids, [BMIM][Cl] and [BMIM][DCA], and the thermotropic liquid crystal 5CB. Better accuracy of VOC prediction is obtained for the hybrid gels composed of a PDMS matrix combined with the [BMIM][Cl] ionic liquid, and the use of this hydrophobic matrix reduces the effect of humidity on the sensing performance when compared to the gelatin counterpart. VOCs interact with all the moieties of the hybrid gel multicomponent system; thus, VOC correct classification depends not only on the polymeric matrix used, but also on the IL selected, which seems to be key to achieve VOCs discrimination at 50% RH. Thus, hybrid gels’ tunable formulation offers the potential for designing complementary sensors for e-nose systems operable under different RH conditions. publishersversion published
- Published
- 2023
- Full Text
- View/download PDF
33. Computer Simulations of a Twist Bend Nematic (NTB): A Coarse-Grained Simulation of the Phase Behaviour of the Liquid Crystal Dimer CB7CB
- Author
-
Mark Wilson and Gary Yu
- Subjects
Inorganic Chemistry ,General Chemical Engineering ,General Materials Science ,liquid crystals ,twist-bend nematic ,coarse-graining ,dimer ,molecular dynamics ,Condensed Matter Physics - Abstract
In recent years, a number of achiral liquid crystal dimer molecules have been shown to exhibit nematic–nematic phase transitions. The lower temperature phase has been identified as the NTB phase, which demonstrates emergent chirality in the spontaneous formation of a heliconical structure. Recent fully atomistic simulations of the molecule CB7CB (1,7-bis-4-(4′-cyanobiphenyl) heptane), a dimer with an odd number of carbon spacers between the mesogenic parts of the molecule, have captured the NTB–N–I phase sequence, providing a picture of the order at a molecular level. In this paper, we use atomistic simulations of CB7CB to develop a coarse-grained model using systematic coarse graining in the NTB phase. We use both force matching (in the form of the MS-CG method) and iterative Boltzmann inversion (IBI) methodologies. Both techniques capture the heliconical order within the NTB phase. Moreover, the model developed via force matching is shown to provide an excellent representation of the atomistic simulation reference model and, remarkably, demonstrates good transferability across temperatures, allowing the NTB–N and N–I phase transitions to be simulated. We also compare results with those of a Martini 3-based coarse-grained model.
- Published
- 2023
- Full Text
- View/download PDF
34. Endurance performance of transmissive liquid crystal phase and polarization controllers for kW-class high-power lasers
- Author
-
Yoshiki Keisuke and Yamamoto Takeshi
- Subjects
Liquid crystals ,Sapphire Polarization ,High power lasers ,Thermal effects ,Temperature distribution ,Thermal lensing - Abstract
This study developed a Liquid Crystal (LC) device that incorporated lasers for machining with output power of the order of kW. The use of sapphire as a substrate along with an appropriate cooling system facilitated the LCs in enabling the control of the phase and polarization of high-power laser light, which is not possible in case of conventional LCs. The exposure of LCs to high-power laser light results in heat accumulation, which causes the destruction of the LC cells. As photochemical damage has a lower occurrence probability at longer wavelengths, the promotion of heat radiation is an important strategy for the application of LCs to near infrared laser beams. The phase control of laser beams up to 6 kW was achieved using the proposed LC substrate as a cooling plate and optimizing the cooling system. Moreover, we compensated for the variation in the properties of the LC with temperature via adjustments to the drive voltage of the LC.
- Published
- 2023
35. Mesogenic Groups Control the Emitter Orientation in Multi‐Resonance TADF Emitter Films**
- Author
-
Dongyang Chen, Francisco Tenopala‐Carmona, Julius A. Knöller, Andreas Mischok, David Hall, Subeesh Madayanad Suresh, Tomas Matulaitis, Yoann Olivier, Pierre Nacke, Frank Gießelmann, Sabine Laschat, Malte C. Gather, Eli Zysman‐Colman, EPSRC, The Leverhulme Trust, The Royal Society, European Commission, University of St Andrews. EaSTCHEM, University of St Andrews. School of Chemistry, University of St Andrews. School of Physics and Astronomy, University of St Andrews. Institute of Behavioural and Neural Sciences, and University of St Andrews. Centre for Energy Ethics
- Subjects
MCC ,Transition Dipole Moment ,TADF ,OLEDs ,DAS ,General Chemistry ,General Medicine ,QD Chemistry ,Catalysis ,Liquid Crystals ,OLED ,Liquid crystal ,QD ,Transition dipole moment ,Thermally Activated Delayed Fluorescence - Abstract
Funding: Engineering and Physical Sciences Research Council - EP/P010482/1; Leverhulme Trust - RPG-2016-047; Royal Society - SRF\R1\201089; China Scholarship Council - 201603780001; Horizon 2020 Framework Programme - 838885; Fonds De La Recherche Scientifique - FNRS - 2.5020.11; Fonds De La Recherche Scientifique - FNRS - F.4534.21; Horizon 2020 Framework Programme - 101023743. The use of thermally activated delayed fluorescence (TADF) emitters and emitters that show preferential horizontal orientation of their transition dipole moment (TDM) are two emerging strategies to enhance the efficiency of OLEDs. We present the first example of a liquid crystalline multi-resonance TADF (MR-TADF) emitter, DiKTa-LC. The compound possesses a nematic liquid crystalline phase between 80 °C and 110 °C. Importantly, the TDM of the spin-coated film shows preferential horizontal orientation, with an anisotropy factor, a, of 0.28, which is preserved in doped poly(vinylcarbazole) films. Green-emitting (λEL = 492 nm) solution-processed OLEDs based on DiKTa-LC showed an EQEmax of 13.6%. We thus demonstrate for the first time how self-assembly of a liquid crystalline TADF emitter can lead to the so-far elusive control of the orientation of the transition dipole in solution-processed films, which will be of relevance for high-performance solution-processed OLEDs. Publisher PDF
- Published
- 2023
36. Conformational and Supramolecular Aspects in Chirality of Flexible Camphor-Containing Schiff Base as an Inducer of Helical Liquid Crystals
- Author
-
Vladimir Burmistrov, Alena Batrakova, Viktor Aleksandriiskii, Igor Novikov, Konstantin Belov, Ilya Khodov, and Oskar Koifman
- Subjects
camphor-containing Schiff base ,conformation ,association ,chirality ,liquid crystals ,inducer ,helical twisting power ,Chemistry (miscellaneous) ,Organic Chemistry ,Drug Discovery ,Molecular Medicine ,Pharmaceutical Science ,Physical and Theoretical Chemistry ,Analytical Chemistry - Abstract
The experimental and theoretical study of influence of the conformational state and association on the chirality of the stereochemically nonrigid biologically active bis-camphorolidenpropylenediamine (CPDA) and its ability to induce the helical mesophase of alkoxycyanobiphenyls liquid–crystalline binary mixture was carried out. On the basis of quantum-chemical simulation of the CPDA structure, four relatively stable conformers were detected. A comparison of the calculated and experimental electronic circular dichroism (ECD) and 1H, 13C, 15N NMR spectra, as well as specific optical rotation and dipole moments, allowed to establish the most probable trans-gauche conformational state (tg) of dicamphorodiimine and CPDA dimer with a predominantly mutually parallel arrangement of molecular dipoles. The induction of helical phases in LC mixtures based on cyanobiphenyls and bis-camphorolidenpropylenediamine was studied by polarization microscopy. The clearance temperatures and the helix pitch of the mesophases were measured. The helical twisting power (HTP) was calculated. The decrease in HTP with increasing dopant concentration was shown to be connected with the CPDA association process in the LC phase. The effect of camphor-containing chiral dopants of various structures on nematic LCs was compared. The values of the permittivity and birefringence components of the CPDA solutions in CB-2 were measured experimentally. A strong effect of this dopant on the anisotropic physical properties of the induced chiral nematic was established. A significant decrease in the dielectric anisotropy was associated with the 3D compensation of the LC dipoles during the formation of the helix.
- Published
- 2023
- Full Text
- View/download PDF
37. Evaporation-Driven Liquid-Liquid Crystalline Phase Separation in Droplets of Anisotropic Colloids
- Author
-
Hamed Almohammadi, Yutong Fu, and Raffaele Mezzenga
- Subjects
drying droplet ,amyloid fibrils ,liquid crystals ,cholesteric patterns ,evaporation-induced phase separation ,spinodal decomposition ,nucleation and growth ,General Engineering ,General Physics and Astronomy ,General Materials Science - Abstract
Drying a colloidal droplet involves complex physics that is often accompanied by evaporation-induced concentration gradients inside of the droplet, offering a platform for fundamental and technological opportunities, including self-assembly, thin film deposition, microfabrication, and DNA stretching. Here, we investigate the drying, liquid crystalline structures, and deposit patterns of colloidal liquid crystalline droplets undergoing liquid-liquid crystalline phase separation (LLCPS) during evaporation. We show that evaporation-induced progressive up-concentration inside the drying droplets makes it possible to cross, at different speeds, various thermodynamic stability states in solutions of amyloid fibril rigid filamentous colloids, thus allowing access to both metastable states, where phase separation occurs via nucleation and growth, as well as to unstable states, where phase separation occurs via the more elusive spinodal decomposition, leading to the formation of liquid crystalline microdroplets (or tactoids) of different shapes. We present the tactoids "phase diagram" as a function of the position within the droplet and elucidate their hydrodynamics. Furthermore, we demonstrate that the presence of the amyloid fibrils not only does not enhance the pinning behavior during droplet evaporation but also slightly suppresses it, thus minimizing the coffee-ring effect. We observed that microsize domains with cholesteric structure emerge in the drying droplet close to the droplet's initial edge, yet such domains are not connected to form a uniform cholesteric dried film. Finally, we demonstrate that a fully cholesteric dried layer can be generated from the drying droplets by regulating the kinetics of the evaporation process. ISSN:1936-0851 ISSN:1936-086X
- Published
- 2023
38. Exploiting the Thermotropic Behavior of Hydroxypropyl Cellulose to Produce Edible Photonic Pigments
- Author
-
Siyi Ming, Xiaotian Zhang, Chun Lam Clement Chan, Zhen Wang, Mélanie M. Bay, Richard M. Parker, Silvia Vignolini, Ming, S [0000-0001-8886-7722], Zhang, X [0000-0001-8812-0952], Chan, CLC [0000-0002-5812-8440], Wang, Z [0000-0002-0331-8271], Bay, MM [0000-0001-8394-6712], Parker, RM [0000-0002-4096-9161], Vignolini, S [0000-0003-0664-1418], and Apollo - University of Cambridge Repository
- Subjects
microparticles ,liquid crystals ,Renewable Energy, Sustainability and the Environment ,hydroxypropyl cellulose ,edible pigments ,structural colors ,General Environmental Science - Abstract
Funder: Chinese Scholarship Council : Cambridge Scholarship, Funder: Croucher Foundation : Cambridge International Scholarship, Hydroxypropyl cellulose (HPC) is a widely commercialized cellulose derivative. While it is typically used as a binder or stabilizer for foods and pharmaceuticals, it can also form a cholesteric liquid crystal in aqueous solution. Moreover, at high HPC concentrations this lyotropic and thermotropic mesophase is known to reflect structural color. However, it remains a challenge to retain this vibrant coloration into the solid state. Here, by combining the emulsification of a HPC mesophase with drying at elevated temperature, we produce solid microparticles that can reflect color across the visible spectrum, from blue to green and red. This method provides a facile and scalable pathway to fabricate structurally colored, edible pigments, which can displace existing synthetic additives used in a wide range of foods and cosmetics.
- Published
- 2023
39. Effect of Mesogenic Phase and Structure of Liquid Crystals on Tribological Properties as Lubricant Additives
- Author
-
Han Wu, Ying Jiang, Wenjing Hu, Sijing Feng, and Jiusheng Li
- Subjects
Materials Chemistry ,liquid crystals ,mesogenic-phase temperature ranges ,lubricant additives ,tribological property ,Surfaces and Interfaces ,Surfaces, Coatings and Films - Abstract
To develop a high-performance additive that can meet different operating conditions, three liquid crystals (LCs) were developed as additives for a base oil. The structures and thermal stabilities of the obtained LCs were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, mass spectroscopy (MS), and thermogravimetric analysis (TGA). The effects of mesogenic-phase temperature ranges on tribological properties were analyzed using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). UMT-TriboLab friction and wear tester was used to study the friction-reducing properties of LCs. The width of wear marks was observed by a Contour GT-K 3D profiler to illustrate the anti-wear performance of LCs. The friction surface was characterized by scanning electron microscopy (SEM) and Raman spectroscopy. It was demonstrated that, in comparison with the base oil, the addition of LCs caused a remarkable reduction in the coefficient of friction (21.57%) and wear width (31.82%). In addition, LCs show better tribological abilities in the mesogenic-phase temperature ranges. According to the results, we demonstrated that LCs can be used as lubricant additives, especially for several operating conditions under specific temperatures.
- Published
- 2023
- Full Text
- View/download PDF
40. Solid-State and Solution Self-assembly Properties of Mono- and Bis-acetylide Ru-II Complexes Bearing Hydrogen-Bonding Amide Functions
- Author
-
Olivier Galangau, Elsa Caytan, William T. Gallonde, Isabelle de Waele, Franck Camerel, Stéphane Rigaut, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), GENCI [2020-AP010811752, 2021-A0100805032, 2021-AP0090811914], Agence Nationale de la Recherche (SAMAT) [ANR-21-CE06-0012-01], and ANR-21-CE06-0012,SAMAT,Complexes Métaux-acétylures auto-organisés pour le thermoélectrique organique(2021)
- Subjects
Inorganic Chemistry ,Liquid crystals ,Metallomesogens ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,Self-assembly ,Ru acetylides ,Hydrogen bonds - Abstract
International audience; In this work, we report our latest results regarding the self-assembly properties of two Ru-acetylides complexes and their corresponding free organic ligands, in solution and in the solid state. The four compounds show mesogenic properties, which we have rationalized thanks to extensive DSC, SAXS, POM, FTIR and molecular dynamic investigations. We clearly establish that hydrogen bonds stabilize the supramolecular structures, and that introducing the metal center and its coordination sphere induces large change in the liquid crystal properties. In addition, for the monoacetylide compound Ru-2, solution-state studies helped us rationalize its supramolecular abilities. In particular, we demonstrate that Ru-2 follows an isodesmic growth supramolecular polymerization in aromatic solvent.
- Published
- 2023
41. An Insight into the Viscoelasticity of Self-Assembling Smectic Liquid Crystals of Colloidal Rods from Active Microrheology Simulations
- Author
-
García Daza, Fabián, Puertas, Antonio M., Cuetos, Alejandro, and Patti, Alessandro
- Subjects
Dynamic Monte Carlo simulations ,Colloids ,Brownian motion ,Microrheology ,Liquid Crystals - Abstract
The rheology of colloidal suspensions is of utmost importance in an ample variety of interdisciplinary applications in formulation technology, determining equally interesting questions in fundamental science. This is especially intriguing when colloids exhibit a degree of long-range positional or orientational ordering, as in liquid crystals (LCs) of elongated particles. Along with standard methods, microrheology (MR) has emerged in recent years as a tool to assess the mechanical properties of materials at the microscopic level. In particular, by active MR one can infer the viscoelastic response of a soft material from the dynamics of a tracer particle being dragged through it by external forces. Although considerable efforts have been made to study the diffusion of guest particles in LCs, little is known on the combined effect of tracer size and directionality of the dragging force on the system’s viscoelastic response. By dynamic Monte Carlo simulations, we apply active MR to investigate the viscoelasticity of self-assembling smectic (Sm) LCs consisting of rod-like particles. In particular, we track the motion of a spherical tracer whose size is varied within a range of values matching the system’s characteristic length scales and being dragged by constant forces that are parallel, perpendicular or at 45◦ to the nematic director. Our results reveal a uniform value of the effective friction coefficient as probed by the tracer at small and large forces, whereas a nonlinear, force-thinning regime is observed at intermediate forces. However, at relatively weak forces the effective friction is strongly determined by correlations between the tracer size and the structure of the host fluid. Moreover, we also show that external forces forming an angle with the nematic director provide additional details that cannot be simply inferred from the mere analysis of parallel and perpendicular forces. Our results highlight the fundamental interplay between tracer size and force direction in assessing the MR of Sm LC fluids., F.A.G.D. was funded by the NextGenerationEU program of the European Union, the Plan de Recuperación, Transformación y Resiliencia, and the Ministerio de Universidades, as part of the “Maria Zambrano” grants for the requalification of the Spanish university system 2021-2023 called by the Pablo de Olavide University., F.A.G.D., A.M.P and A.P. acknowledge the International Exchanges Grant IES\R1\191066, awarded by The Royal Society, A.P. is supported by a “Maria Zambrano Senior” researcher fellowship, financed by the European Union within the NextGenerationEU program and the Spanish Ministry of Universities., A.M.P. acknowledges financial support from project PID2021-127836NB-I00 (funded by MCIN/AEI/10.13039/501100011033/ FEDER “A way to make Europe”)., A. C. acknowledges support from Consejería de Transformación Económica, Industria, Conocimiento y Universidades de la Junta de Andalucía/FEDER (project grant P20-00816), and from the Spanish Ministerio de Ciencia, Innovación y Universidades, and FEDER (project grant PPID2021-126121NB-I00)., The authors acknowledge the C3UPO of the Pablo de Olavide University for the support with HPC facilities and the use of the Computational Shared Facility at The University of Manchester
- Published
- 2023
42. Control of colloidal self-assembly by liquid-liquid crystalline phase separation
- Author
-
Almohammadi, Hamed
- Subjects
amyloid fibrils ,liquid crystals ,Nucleation and growth ,Physics ,Tactoids ,microfluidics ,Colloids ,liquid liquid phase separation ,Cellulose - Abstract
Nucleation and growth (N&G) -the mechanism of forming a new thermodynamic phase- is one of the most important physical phenomena underlying gas-liquid (GLPS), liquid-liquid (LLPS), and solid-liquid (SLPS) phase separation. In principle, the phase transition rate and properties of the emerging new phase, such as the shape, structure, and size distribution, are determined by the interplay between thermodynamics and kinetics of N&G. In heterogeneous colloidal systems based on filamentous biological colloids, N&G occurs via a distinct phase separation mechanism and bears both fundamental and technological significance. In this system, the phase separation is purely entropic - a phenomenon recognized as liquid-liquid crystalline phase separation (LLCPS)- and two separate vertical lines define the two-phase region's binodal curve. Within binodal concentrations, where isotropic and nematic phases co-exist, orientational fluctuations of constituting filaments drive N&G that proceeds via the spontaneous formation of microdroplets of the nematic phase in the isotropic phase. These microdroplets, called tactoids, offer a rich liquid crystalline phase behavior and are now emerging as interesting components for structural investigations and developing new materials. Upon growth of tactoids with time, with induction time in the order of hours to days, their self-selected shape, composition, and structure change following volume-compositions trajectories, that approach two vertical binodal asymptotes. This implies that our understanding of heterogeneous colloidal systems is restricted to the N&G paradigm relying on the interplay between thermodynamics and kinetics, and it remains a hurdle to intervene in tactoids growth progress and thus control the induction time, shape, size, composition, orientation, and structure of tactoids. In this thesis, on the fundamental side, we study effects of kinetics on phase separation by separating them from thermodynamics in heterogeneous colloidal systems. This, besides insights from non-equilibrium features of tactoids, enables us, on the practical side, to address long-lasting challenges in liquid crystals, including the need for more control over tactoids formation in terms of the shape and internal structures, formation time, stability, orientation, internal components, and density of tactoids. Specifically, we first examine non-equilibrium features of liquid crystalline tactoids. By carefully designing a microfluidic system, we expose tactoids to an extensional flow field, showing that the shape of tactoids can be manipulated by hydrodynamic forces, allowing us to induce structural transformation and tune the self-assembly structure in tactoids. We combine free energy functional theory and experimental measurements to rationalize how liquid crystalline structures change when the confinement shape changes. Additionally, we study the shape and structural deformation of tactoids under shear flow, enabling us to deform tactoids in a different direction with respect to the collective orientation of colloids within tactoids. Next, we study the shape and structural relaxation of tactoids when they are released from an out-of-equilibrium state, allowing us to disentangle kinetics of the self-assembly of tactoids from shape dynamics. Based on insights obtained from tactoids' out-of-equilibrium properties, we show, by carefully selecting colloidal systems and controlling phase separation in microfluidic devices, that it becomes possible to disentangle kinetics effects from thermodynamics to form tactoids. Using rod-like colloids, we extrude a solution set at one thermodynamic nematic branch inside the other isotropic branch, realizing nematic or cholesteric droplets where the composition is set by thermodynamics, while dynamic flow parameters define the structure and morphology. Our results unveil new physical phenomena, such as orders of magnitude shorter timescales of tactoids formation, a wider phase diagram for tactoids, and internal cholesteric structures that are not observable via the N&G pathway. Our approach enables the on-demand fabrication of multicomponent heterogeneous liquid crystal jets/tactoids, enhancing their potential and introducing new fundamental and technological directions in hybrid structured fluids. Finally, we show that evaporation-induced progressive up-concentration inside of drying droplets makes it possible to cross, at different speeds, various thermodynamic stability states in solutions of rigid colloids. This allows us to access both metastable states, where phase separation occurs via N&G, and unstable states, where phase separation occurs via the more elusive spinodal decomposition, leading to the formation of tactoids of different shapes. Our findings not only deepen our understanding of the fundamental interplay between kinetics and thermodynamics in the formation of heterogeneous colloidal systems and out-of-equilibrium features of liquid crystalline systems, but they may also spark previously unanticipated opportunities in physics, biophysics, materials science, and the numerous technological applications that rely on N&G.
- Published
- 2023
- Full Text
- View/download PDF
43. Towards Quantitative Wall Shear Stress Measurements: A Comparative Study on the Impact of RGB-to-Hue-Conversion Algorithms for Liquid Crystal Diagnostics
- Author
-
Melekidis, Stefanos, Elfner, Maximilian, and Bauer, Hans Jörg
- Subjects
liquid crystals ,hue conversion ,experimental data ,ddc:620 ,calibration ,wall shear stress ,Engineering & allied operations ,image processing - Abstract
Liquid crystal diagnostics is a capable tool for determining quantitative wall shear stress distributions with high spatial resolution, which can be applied to almost any surface shape. A standard consumer camera is typically used to record the scattered light of the liquid crystals as red, green, and blue RGB data. This RGB data has to be converted to a hue-based color space in order to perform a state-of-the-art calibration procedure. Algorithms for this purpose are numerous in the literature. However, a considerable number of them show a wide range of resulting hue values due to different trigonometric relations. This renders some conversion algorithms unsuitable for calculating physical wall shear stresses, as their magnitude and distribution depend on the conversion algorithm used. For this reason, the choice of an inappropriate conversion algorithm may compromise the measurement accuracy and subsequent comparability significantly. The main objective of this paper is to give recommendations for the use of appropriate algorithms to determine physical wall shear stresses. In a first step, synthetic liquid crystal data is converted using algorithms described in the literature. The preselected algorithms are then applied to liquid crystal data from a flat plate wind tunnel experiment to illustrate their influence on the determined uncalibrated wall shear stress distribution. The final discussion serves as guidelines for the post-processing of liquid crystal data and their subsequent comparability.
- Published
- 2023
44. Investigation of new solitons in nematic liquid crystals with Kerr and non-Kerr law nonlinearities
- Author
-
Nauman Raza, Saima Arshed, Asma Rashid Butt, Mustafa Inc, Shao-Wen Yao, and Mühendislik ve Doğa Bilimleri Fakültesi
- Subjects
Optical Solitons ,Physics and Astronomy (miscellaneous) ,Kudryashov's Method ,Non-Kerr Nonlinearities ,The Tanh-Coth Method ,Nematicons ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Liquid Crystals - Abstract
Nematicons became a key topic of interest in liquid crystal technology in recent years. This paper contributes in understanding the fantastic features of nematicons in optics and further disciplines. This piece of research investigates nematicons for obtaining various exact solutions for Kerr and non-Kerr law nonlinearities with the help of the Kudryashov’s approach and the tanh–coth technique. The acquired outcomes involve rational, periodic and hyperbolic solutions as well as their combo-type solutions for all the four cases of nonlinearity. A comparative study is conducted to show the novelty of present results with results already existing in the literature. The constraint conditions obtained ensured that the existence of these solutions is extraordinarily favorable to further investigate the dynamics of nematicons for various kinds of nonlinearity. The dynamics of the few of the obtained solutions are also discussed by 3D plots.
- Published
- 2023
45. Investigation of exact soliton solutions of nematicons in liquid crystals according to nonlinearity conditions
- Author
-
Hülya Durur, Asıf Yokuş, Serbay Duran, and Rektörlük, Bilişim Teknolojileri Uygulama ve Araştırma Merkezi
- Subjects
Statistical and Nonlinear Physics ,Condensed Matter Physics ,(1/G ′) -expansion method ,Kerr and Power Law ,liquid crystals ,Nematicons - Abstract
In this work, new traveling wave solutions are generated for the system that models nematicons in liquid crystals using the [Formula: see text]-expansion method. In the equation system, nonlinearity is taken into account for Kerr law and Power law. Also, the existence of exact solutions under restriction conditions is guaranteed. We suggest that the solutions produced are of a different type than the solutions in the literature. Figures representing the intensity of the produced traveling wave solutions are presented. In addition, the simulation of the solitary wave is made for different values of the parameter that affects the inclination angle of the molecules in the nematicons mechanism in liquid crystals. How classical solitary wave behavior translates into triangular wave behavior is discussed. We believe this paper will provide an important perspective on the problems encountered in various application areas such as fluid dynamics, chemical engineering, chaos and complex networks in terms of investigating different mechanisms by taking into account nonlinearity factors.
- Published
- 2023
46. Photomechanical response under physiological conditions of azobenzene-containing 4D-printed liquid crystal elastomer actuators
- Author
-
Lorena Ceamanos, Dirk J. Mulder, Zehra Kahveci, María López-Valdeolivas, Albert P. H. J. Schenning, Carlos Sánchez-Somolinos, Stimuli-responsive Funct. Materials & Dev., ICMS Core, EIRES Chem. for Sustainable Energy Systems, and Institute for Complex Molecular Systems
- Subjects
Elastomers ,Biomedical Engineering ,Bioengineering ,General Materials Science ,General Chemistry ,General Medicine ,Azo Compounds ,Liquid Crystals - Abstract
Soft and mechanically responsive actuators hold the promise to revolutionize the design and manufacturing of devices in the areas of microfluidics, soft robotics and biomedical engineering. In many of these applications, the actuators need to operate in a wet environment that can strongly affect their performance. In this paper, we report on the photomechanical response in a biological buffer of azobenzene-containing liquid crystal elastomer (LCE)-based actuators, prepared by four-dimensional (4D) printing. Although the photothermal contribution to the photoresponse is largely cancelled by the heat withdrawing capacity of the employed buffer, a significant photoinduced reversible contraction, in the range of 7% of its initial length, has been achieved under load, taking just a few seconds to reach half of the maximum contraction. Effective photomechanical work performance under physiological conditions has, therefore, been demonstrated in the 4D-printed actuators. Advantageously, the photomechanical response is not sensitive to salts present in the buffer differently to hydrogels with responses highly dependent on the fluid composition. Our work highlights the capabilities of photomechanical actuators, created using 4D printing, when operating under physiological conditions, thus showing their potential for application in the microfluidics and biomedical fields.
- Published
- 2023
47. Uni- and bidirectional rotation and speed control in chiral photonic micromotors powered by light
- Author
-
Yera Ye. Ussembayev, Noah De Witte, Xiaohong Liu, Alberto Belmonte, Tom Bus, Sjoukje Lubach, Filip Beunis, Filip Strubbe, Albert P. H. J. Schenning, Kristiaan Neyts, Stimuli-responsive Funct. Materials & Dev., ICMS Core, EIRES Chem. for Sustainable Energy Systems, and Institute for Complex Molecular Systems
- Subjects
microparticles ,optical torque ,Technology and Engineering ,optical tweezers ,General Chemistry ,actuators ,sensors ,Biomaterials ,Chemistry ,liquid crystals ,Physics and Astronomy ,optical ,tweezers ,General Materials Science ,Biotechnology - Abstract
Liquid crystalline polymers are attractive materials for untethered miniature soft robots. When they contain azo dyes, they acquire light-responsive actuation properties. However, the manipulation of such photoresponsive polymers at the micrometer scale remains largely unexplored. Here, uni- and bidirectional rotation and speed control of polymerized azo-containing chiral liquid crystalline photonic microparticles powered by light is reported. The rotation of these polymer particles is first studied in an optical trap experimentally and theoretically. The micro-sized polymer particles respond to the handedness of a circularly polarized trapping laser due to their chirality and exhibit uni- and bidirectional rotation depending on their alignment within the optical tweezers. The attained optical torque causes the particles to spin with a rotation rate of several hertz. The angular speed can be controlled by small structural changes, induced by ultraviolet (UV) light absorption. After switching off the UV illumination, the particle recovers its rotation speed. The results provide evidence of uni- and bidirectional motion and speed control in light-responsive polymer particles and offer a new way to devise light-controlled rotary microengines at the micrometer scale.
- Published
- 2023
48. A supramolecular and liquid crystalline water‐based alignment medium based on azobenzene‐substituted 1,3,5‐benzenetricarboxamides
- Author
-
Kevin Knoll, Dominik Herold, Max Hirschmann, and Christina M. Thiele
- Subjects
Magnetic Resonance Spectroscopy ,Water ,General Materials Science ,General Chemistry ,Azo Compounds ,Liquid Crystals - Abstract
A supramolecular, lyotropic liquid crystalline alignment medium based on an azobenzene‐containing 1,3,5‐benzenetricarboxamide (BTA) building block is described and investigated. As we demonstrate, this water‐based system is suitable for the investigation of various water‐soluble analytes and allows for a scaling of alignment strength through variation of temperature. Additionally, alignment is shown to reversibly collapse above a certain temperature, yielding an isotropic solution. This collapse allows for isotropic reference measurements, which are typically needed in addition to those in an anisotropic environment, to be performed using the same sample just by varying the temperature. The medium described thus provides easy access to anisotropic NMR observables and simplifies structure elucidation techniques based thereon.
- Published
- 2022
49. Recyclable Periodic Nanostructure Formed by Sublimable Liquid Crystals for Robust Cell Alignment
- Author
-
Min Jeong Shin, San Hae Im, Wantae Kim, Hyungju Ahn, Tae Joo Shin, Hyun Jung Chung, and Dong Ki Yoon
- Subjects
Osmium Tetroxide ,Electrochemistry ,General Materials Science ,Surfaces and Interfaces ,Condensed Matter Physics ,Spectroscopy ,Liquid Crystals ,Nanostructures - Abstract
We demonstrate a facile method to fabricate a recyclable cell-alignment scaffold using nanogrooves based on sublimable liquid crystal (LC) material. Randomly and uniaxially arranged smectic LC structures are obtained, followed by sublimation and recondensation processes, which directly produce periodic nanogrooves with dimensions of a couple of hundreds of nanometers. After treatment with osmium tetroxide (OsO
- Published
- 2022
50. Liquid Crystal Nanoparticles Enhance Tobramycin Efficacy in a Murine Model of Pseudomonas aeruginosa Biofilm Wound Infection
- Author
-
Chelsea R. Thorn, Anthony Wignall, Zlatko Kopecki, Anita Kral, Clive A. Prestidge, Nicky Thomas, Thorn, Chelsea R, Wignall, Anthony, Kopecki, Zlatko, Kral, Anita, Prestidge, Clive A, and Thomas, Nicky
- Subjects
in vivo ,liquid crystals ,P. aeruginosa ,Infectious Diseases ,tobramycin ,biofilm - Abstract
Refereed/Peer-reviewed Chronic Pseudomonas aeruginosa wound infections are highly prevalent and often untreatable due to biofilm formation, resulting in high antimicrobial tolerance. Standard antibiotic therapy for P. aeruginosa infections involves tobramycin, yet it is highly ineffective as monotherapy as tobramycin cannot penetrate the biofilm to elicit its antimicrobial effect. Lipid liquid crystal nanoparticles (LCNPs) have previously been shown to increase the antimicrobial efficacy and penetration of tobramycin against P. aeruginosa biofilms in vitro and ex vivo. Here, for the first time, we have developed a chronic P. aeruginosa biofilm infection in full-thickness wounds in mice to examine the potential of LCNPs to improve the effect of tobramycin, preclinically. After three doses, administered once a day, tobramycin-LCNPs significantly reduced the P. aeruginosa bacterial load in murine wounds 1000-fold more than unformulated tobramycin, which in turn showed no significant difference to the saline control treatment. Consistent with the improved P. aeruginosa eradication, the tobramycin-LCNPs promoted wound healing. In comparison to previous in vitro and ex vivo data, we show a strong in vitro-in vivo correlation between P. aeruginosa biofilm infection models. The enhanced activity of tobramycin-LCNPs in vivo in the preclinical murine model demonstrates the strong potential of LCNPs as a next-generation formulation approach to improve the efficacy of tobramycin against P. aeruginosa biofilm wound infections.
- Published
- 2022
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.