Freestanding Silver-Doped Zinc Oxide 2D Crystals Synthesized by a Surface Energy-Controlled Hydrothermal Strategy

2021 ◽  
Author(s):  
Itishree Pradhan ◽  
Arkamita Bandyopadhyay ◽  
Alpana Nayak ◽  
Prashant Kumar
Keyword(s):  
Zinc Oxide ◽  
Surface Energy ◽  
2D Crystals

The role of polarity and surface energy in the growth mechanism of ZnO from nanorods to nanotubes

CrystEngComm ◽  
2016 ◽  
Vol 18 (5) ◽  
pp. 779-786 ◽  
Author(s):  
Kwong-Lung Ching ◽  
Guijun Li ◽  
Yeuk-Lung Ho ◽  
Hoi-Sing Kwok
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Surface Energy ◽  
Growth Mechanism ◽  
Electronic Devices ◽  
Zinc Oxide Nanostructures ◽  
Electrical And Optical Properties ◽  
Oxide Nanostructures

The polarity of zinc oxide nanostructures is crucial to modern electronic devices in terms of electrical and optical properties.

scholarly journals The Applicability of a Drop Penetration Method to Measure Contact Angles on TiO2 and ZnO Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1099 ◽  
Author(s):  
Sabrina M. Garner ◽  
Edgar A. O’Rear ◽  
Sharukh Soli Khajotia ◽  
Fernando Luis Esteban Florez
Keyword(s):  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Surface Energy ◽  
Ethylene Glycol ◽  
Zno Nanoparticles ◽  
Selection Criteria ◽  
Reasonable Agreement ◽  
Contact Angles ◽  
Energy Components

In this study, six solvents (water, diiodomethane, bromonaphthalene, formamide, ethanol and ethylene glycol) were examined for three nanoparticle substrates, zinc oxide and titanium dioxide (21 nm and 100 nm), with the goal of assessing the suitability of a modified drop penetration method (DPM) for orders of magnitude smaller particles. Nanoparticles were compressed into flat discs and the solvent dropped on the surface while the image with time was recorded. Contact angles were in reasonable agreement with literature over the range of 20–80°, but failed to provide acceptable results for surface energy components. It was necessary to eliminate certain solvents and substrates not meeting the selection criteria.

A Thermodynamic Theory of Rubber Fillers

1929 ◽  
Vol 2 (2) ◽  
pp. 275-277
Author(s):  
Lothar Hock
Keyword(s):  
Zinc Oxide ◽  
Free Surface ◽  
Surface Energy ◽  
Free Surface Energy ◽  
Oxide Mixture ◽  
Rubber Mixture ◽  
Basic Principles ◽  
Heat Of Wetting ◽  
Thermal Measurements ◽  
Rubber Component

Abstract Purely thermal measurements indicate that the physical reënforcement of rubber, i. e., the increase in the work expended in rupturing, brought about by the admixture of active fillers, depends upon the free surface energy between rubber and filler, besides a work of friction, and can be measured in absolute units. Experience has shown that the addition of so-called active fillers to rubber improves the physical properties of the latter, the work expended in breaking the rubber mixture being considerably greater than that expended in breaking the pure rubber. Furthermore, it has been found that the finer the active filler, e. g., carbon black or zinc oxide, the greater is the reenforcing effect. Obviously then the wetting of rubber and filler is the cause of the reenforcing action. In developing from these basic principles a theory of the action of fillers, the free surface energy between rubber and filler must be considered responsible for the increased work of breaking the loaded rubber. It is desirable, therefore, to find a way to determine this free surface energy. Now if a rubber-zinc oxide mixture is swollen in benzine, the rubber component swells and the zinc oxide is wet. This process is accompanied by a heat tone which can be measured calorimetrically, and which is not the sum of the heat of swelling of the same quantity of rubber and the heat of wetting of the zinc oxide when these are measured separately, but shows a distinctly different value. This difference represents the heat of adhesion of the filler and rubber. It also represents the total surface energy, and therefore is not a measure of the free surface energy to which is attributed the increase in the work of rupture.

Large area assembly of zinc oxide nanowire arrays by surface energy contrast template

2013 ◽  
Vol 102 ◽  
pp. 48-52 ◽  
Author(s):  
Xiangdong Ye ◽  
Yucheng Ding ◽  
Jin Zhang ◽  
Wenxiu Que
Keyword(s):  
Zinc Oxide ◽  
Surface Energy ◽  
Nanowire Arrays ◽  
Large Area ◽  
Zinc Oxide Nanowire

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

Two-Dimensional Crystallization of Tetanus Toxin

1985 ◽  
Vol 43 ◽  
pp. 528-529
Author(s):  
Jeffry A. Reidler ◽  
John P. Robinson
Keyword(s):  
Electron Microscopy ◽  
Tetanus Toxin ◽  
Structural Information ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Membrane Interface ◽  
3D Reconstructions ◽  
Cellular Receptors ◽  
Computer Reconstruction ◽  
2D Crystals

We have prepared two-dimensional (2D) crystals of tetanus toxin using procedures developed by Uzgiris and Kornberg for the directed production of 2D crystals of monoclonal antibodies at an antigen-phospholipid monolayer interface. The tetanus toxin crystals were formed using a small mole fraction of the natural receptor, GT1, incorporated into phosphatidyl choline monolayers. The crystals formed at low concentration overnight. Two dimensional crystals of this type are particularly useful for structure determination using electron microscopy and computer image refinement. Three dimensional (3D) structural information can be derived from these crystals by computer reconstruction of photographs of toxin crystals taken at different tilt angles. Such 3D reconstructions may help elucidate the mechanism of entry of the enzymatic subunit of toxins into cells, particularly since these crystals form directly on a membrane interface at similar concentrations of ganglioside GT1 to the natural cellular receptors.

Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

1996 ◽  
Vol 54 ◽  
pp. 174-175
Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transmission Electron Microscope ◽  
Rolling Resistance ◽  
Synthetic Polymers ◽  
Nitrogen Atmosphere ◽  
Transmission Electron ◽  
Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

Cryo-Electron Microscopy and Correlation Averaging of Frozen-Hydrated, Polymorphic 2D Crystals of the Mitochondrial Outer Membrane Channel

1990 ◽  
Vol 48 (1) ◽  
pp. 100-101
Author(s):  
Xiao-Wei Guo
Keyword(s):  
Outer Membrane ◽  
Hexagonal Lattice ◽  
Mitochondrial Outer Membrane ◽  
Rectangular Lattice ◽  
Electron Microscopic ◽  
Cryo Electron Microscopy ◽  
Voltage Dependent ◽  
Outer Membrane Channel ◽  
2D Crystals ◽  
Vdac Channel

Voltage-dependent, anion-selective channels (VDAC) are formed in the mitochondrial outer membrane (mitOM) by a 30-kDa polypeptide. These channels form ordered 2D arrays when mitOMs from Neurospora crassa are treated with soluble phospholipase A2. We obtain low-dose electron microscopic images of unstained specimens of VDAC crystals preserved in vitreous ice, using a Philips EM420 equipped with a Gatan cryo-transfer stage. We then use correlation analysis to compute average projections of the channel crystals. The procedure involves Fourier-filtration of a region within a crystal field to obtain a preliminary average that is subsequently cross-correlated with the entire crystal. Subregions are windowed from the crystal image at coordinates of peaks in the cross-correlation function (CCF, see Figures 1 and 2) and summed to form averages (Figure 3).The VDAC channel forms several different types of crystalline arrays in mitOMs. The polymorph first observed during phospholipase treatment is a parallelogram array (a=13 run, b=11.5 run, θ==109°) containing 6 water-filled pores per unit cell. Figure 1 shows the CCF of a sub-field of such an “oblique” array used to compute the correlation average of Figure 3A. With increased phospholipase treatment, other polymorphs are observed, often co-existing within the same crystal. For example, two distinct (but closely related) types of lattices occur in the field corresponding to the CCF of Figure 2: a “contracted” version of the parallelogram lattice (a=13 run, b=10 run, θ=99°), and a near-rectangular lattice (a=8.5 run, b=5 nm). The pattern of maxima in this CCF suggests that a third, near-hexagonal lattice (a=4.5 nm) may also be present. The correlation averages of Figures 3B-D were computed from polycrystalline fields, using peak coordinates in regions of CCFs corresponding to each of the three lattice types.

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