scholarly journals Shaping nanoparticle fingerprints at the interface of cholesteric droplets

2018 ◽  
Vol 4 (10) ◽  
pp. eaat8597 ◽  
Author(s):  
Lisa Tran ◽  
Hye-Na Kim ◽  
Ningwei Li ◽  
Shu Yang ◽  
Kathleen J. Stebe ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Periodic Structures ◽  
Water Solution ◽  
Cholesteric Liquid Crystal ◽  
Solution Ph ◽  
Surrounding Water ◽  
Particle Assembly ◽  
Interfacial Assembly ◽  
Energy Applications ◽  
Geometric Frustration

The ordering of nanoparticles into predetermined configurations is of importance to the design of advanced technologies. Here, we balance the interfacial energy of nanoparticles against the elastic energy of cholesteric liquid crystals to dynamically shape nanoparticle assemblies at a fluid interface. By adjusting the concentration of surfactant that plays the dual role of tuning the degree of nanoparticle hydrophobicity and altering the molecular anchoring of liquid crystals, we pattern nanoparticles at the interface of cholesteric liquid crystal emulsions. In this system, interfacial assembly is tempered by elastic patterns that arise from the geometric frustration of confined cholesterics. Patterns are tunable by varying both surfactant and chiral dopant concentrations. Adjusting the particle hydrophobicity more finely by regulating the surfactant concentration and solution pH further modifies the rigidity of assemblies, giving rise to surprising assembly dynamics dictated by the underlying elasticity of the cholesteric. Because particle assembly occurs at the interface with the desired structures exposed to the surrounding water solution, we demonstrate that particles can be readily cross-linked and manipulated, forming structures that retain their shape under external perturbations. This study serves as a foundation for better understanding inter-nanoparticle interactions at interfaces by tempering their assembly with elasticity and for creating materials with chemical heterogeneity and linear, periodic structures, essential for optical and energy applications.

scholarly journals Electrically turning periodic structures in cholesteric layer with conical–planar boundary conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Oxana Prishchepa ◽  
Mikhail Krakhalev ◽  
Vladimir Rudyak ◽  
Vitaly Sutormin ◽  
Victor Zyryanov
Keyword(s):  
Boundary Conditions ◽  
Periodic Structures ◽  
Cholesteric Liquid Crystal ◽  
Growth Direction ◽  
Smooth Transition ◽  
Defect Structures ◽  
Optical Cell ◽  
Elastic Continuum ◽  
The One ◽  
Experimental Findings

AbstractElectro-optical cell based on the cholesteric liquid crystal is studied with unique combination of the boundary conditions: conical anchoring on the one substrate and planar anchoring on another one. Periodic structures in cholesteric layer and their transformation under applied electric field are considered by polarizing optical microscopy, the experimental findings are supported by the data of the calculations performed using the extended Frank elastic continuum approach. Such structures are the set of alternating over- and under-twisted defect lines whose azimuthal director angles differ by $$180^\circ$$ 180 ∘ . The $$U^+$$ U + and $$U^-$$ U - -defects of periodicity, which are the smooth transition between the defect lines, are observed at the edge of electrode area. The growth direction of defect lines forming a diffraction grating can be controlled by applying a voltage in the range of $$0\le \, V \le 1.3$$ 0 ≤ V ≤ 1.3  V during the process. Resulting orientation and distance between the lines don’t change under voltage. However, at $$V>1.3$$ V > 1.3  V $$U^+$$ U + -defects move along the defect lines away from the electrode edges, and, finally, the grating lines collapse at the cell’s center. These results open a way for the use of such cholesteric material in applications with periodic defect structures where a periodicity, orientation, and configuration of defects should be adjusted.

Spray-Tank-Mix Compatibility of Manganese, Boron, and Fungicide: Solution pH and Precipitation1

1993 ◽  
Vol 20 (1) ◽  
pp. 44-49 ◽  
Author(s):  
N. L. Powell
Keyword(s):  
Boric Acid ◽  
Foliar Application ◽  
Water Solution ◽  
Inorganic Salts ◽  
Well Water ◽  
Manganese Sulfate ◽  
Solution Ph ◽  
Deep Well ◽  
Cupric Hydroxide ◽  
Disodium Octaborate Tetrahydrate

Abstract Foliar application of manganese and boron mixed with pesticides in water solution is a common practice for peanut (Arachis hypogaea L.) production. This study was conducted to determine the compatibility of mixing manganese, boron, and leafspot fungicides using water from three sources. Spray mixtures of the chelated manganese salt of ethylene diamine tetra-acetate and the inorganic salts of manganese as manganese sulfate(TECMANGAMTM), manganese sulfate monohydrate, manganese chloride, and manganese nitrate were developed using deep-well water, shallow well water, or distilled water. Boron was added to these mixtures using boric acid or disodium octaborate tetrahydrate. In addition, all combinations were mixed with the leafspot fungicides chlorothalonil or cupric hydroxide plus sulfur. Mixtures were equivalent to recommended rates of manganese, boron, and fungicide applied to the foliage in 140 L ha-1 of spray volume. Measurements were made of solution pH and manganese remaining in solution after filtration. Development of precipitates was noted. In the deep-well water solution (pH = 8.0), addition of manganese sulfate, manganese sulfate monohydrate and manganese chloride caused precipitates to form. Manganese nitrate and chelated manganese solutions did not form precipitates. Addition of disodium octaborate tetrahydrate increased the tank-mix pH for all waters source, and caused increased precipitation of the manganese inorganic salts, but not the chelated manganese. Use of boric acid in the water lowered solution pH, and all manganese sources remained in solution. Spray-tank-mix pH was critical in keeping all manganese inorganic salts in solution. For all pH levels studied (pH 4.6 to 8.4) the chelated manganese remained in solution without formation of a precipitate. Chemical analyses of the filtrate showed that only 75 to 80% of the inorganic salts of manganese remained in solution with disodium octaborate tetrahydrate, while 100% of the chelated manganese salt remained in solution. Inorganic salts of manganese and disodium octaborate tetrahydrate should not be mixed with chlorothalonil, and none of the manganese materials should be mixed with cupric hydroxide plus sulfur as a spray-tank-mixture for foliar application.

scholarly journals A Comparative Study of Hydroxyapatite Coating Produced with Plasma Electrolytic Oxidation and Hydrothermal Treatment on Titanium Alloys: Ti6Al4V and Ti6Al7Nb for Dental Implants

2018 ◽  
Author(s):  
Elinor Nahum ◽  
Svetlana Lugovskoy
Keyword(s):  
Dental Implants ◽  
Plasma Electrolytic Oxidation ◽  
Water Solution ◽  
Thickness Gauge ◽  
Solution Ph ◽  
Ti Alloys ◽  
Electrolytic Oxidation ◽  
Water Ph ◽  
Mechanical Properties And Corrosion ◽  
Plasma Electrolytic

Ti and Ti alloys are materials usually used in contact with hard tissue for applications such as artificial joints and dental implants. Ti6Al4V is a very common alloy used for dental implants, owing to its good mechanical properties and corrosion resistance. Nevertheless, because of uncertainties regarding the toxicity of vanadium and its influence on the human body, other Ti alloys containing no vanadium and retaining suitable properties are used. In this work Ti6Al4V and Ti6Al7Nb were oxidized in a water solution of calcium acetate (Ca(CH3COO)2) and calcium glycerophosphate (Ca(PO4CH(CH2OH)2) by Plasma Electrolytic Oxidation (PEO) for 20 minutes and then were hydrothermally treated (HTT) in water (pH=7) and in potassium hydroxide (KOH) solution (pH=11) for 2 hours at 200°C in a pressurized reactor. The surface morphologies, elemental composition and phase components were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD), respectively. The surface roughness was measured by Atomic Force Microscope (AFM) and thickness measurements were made by SEM and thickness gauge. Also, corrosion tests were made to evaluate the corrosion behavior of the two alloys. The aim of this study is to compare two viable Ti alloys, Ti6Al4V and Ti6Al7Nb, and to attain on their surface hydroxyapatite (HA) coating improving the osseointegration, as it simulates a human bone.

Swollen hexagonal liquid crystals as smart nanoreactors: implementation in materials chemistry for energy applications

Nanoscale ◽  
2018 ◽  
Vol 10 (13) ◽  
pp. 5793-5819 ◽  
Author(s):  
Srabanti Ghosh ◽  
Laurence Ramos ◽  
Hynd Remita
Keyword(s):  
Liquid Crystals ◽  
Energy Harvesting ◽  
Materials Chemistry ◽  
Energy Applications

Swollen hexagonal liquid crystals are versatile temples to synthesize nanomaterials for energy harvesting applications.

New liquid crystal formation induced by nanoscale phase separation composed of bent-core liquid crystal and rod-like cholesteric liquid crystal mixtures

Soft Matter ◽  
2021 ◽  
Author(s):  
Yoichi Takanishi
Keyword(s):  
Liquid Crystal ◽  
Phase Separation ◽  
Liquid Crystals ◽  
Small Angle ◽  
Cholesteric Liquid Crystal ◽  
Crystal Formation ◽  
Nano Structure ◽  
X Ray ◽  
Nanoscale Phase Separation ◽  
X Ray Scattering

Herein, the local nano-structure in mixtures of cholesteric liquid crystals and a bent-core molecule was analyzed via the small-angle X-ray scattering.

scholarly journals Fabrication of multicolored patterns based on dye-doped cholesteric liquid crystals

2019 ◽  
Vol 18 (7) ◽  
pp. 1638-1648 ◽  
Author(s):  
Linlin Xu ◽  
Hanbing Zhang ◽  
Jie Wei
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Fluorescence Enhancement ◽  
Cholesteric Liquid Crystal ◽  
Cholesteric Liquid Crystals ◽  
Dual Mode

We developed a type of dye-doped cholesteric liquid crystal, which were used for fluorescence enhancement and dual-mode multicolor patterns.

scholarly journals Quantitation of Acetyl Hexapeptide-8 in Cosmetics by Hydrophilic Interaction Liquid Chromatography Coupled to Photo Diode Array Detection

Separations ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 125 ◽  
Author(s):  
Vasiliki Raikou ◽  
Eleni Kalogria ◽  
Athanasia Varvaresou ◽  
Efthimios Tsirivas ◽  
Irene Panderi
Keyword(s):  
Liquid Chromatography ◽  
Water Solution ◽  
Aging Effect ◽  
Hydrophilic Interaction Liquid Chromatography ◽  
Hydrophilic Interaction ◽  
Solution Ph ◽  
Photodiode Array Detection ◽  
Cosmetic Formulations ◽  
Hydrophilic Peptide ◽  
Array Detection

Bioactive peptides are gaining more and more popularity in the research and development of cosmetic products with anti-aging effect. Acetyl hexapeptide-8 is a hydrophilic peptide incorporated in cosmetics to reduce the under-eye wrinkles and the forehead furrows. Hydrophilic interaction liquid chromatography (HILIC) is the separation technique of choice for analyzing peptides. In this work, a rapid HILIC method coupled to photodiode array detection operated at 214 nm was developed, validated and used to determine acetyl-hexapeptide-8 in cosmetics. Chromatography was performed on a Xbridge® HILIC BEH analytical column using as mobile phase a 40 mM ammonium formate water solution (pH 6.5)-acetonitrile mixture 30:70, v/v at flow rate 0.25 mL min−1. The assay was linear over the concentration range 20 to 30 μg mL−1 for the cosmetic formulations and 0.004 to 0.007% (w/w) for the cosmetic cream. The limits of quantitation for acetyl hexapeptide-8 were 1.5 μg mL−1 and 0.002% (w/w) for the assay of cosmetic formulations and cosmetic creams, respectively. The method was applied to the analysis of cosmetic formulations and anti-wrinkle cosmetic creams.

Sign in / Sign up

Export Citation Format

Share Document