scholarly journals Smart Cotton Functionalized With Self-Implanted Palladium Nanopanicles: Full Ultraviolet Shielding Potency

2021 ◽  
Author(s):  
Hossam E. Emam ◽  
Saad Zaghloul ◽  
Hanan B. Ahmed
Keyword(s):  
Alkaline Medium ◽  
Cotton Fabrics ◽  
Shielding Effect ◽  
Color Strength ◽  
Protection Factor ◽  
Yellowness Index ◽  
Transmission Electron ◽  
Ultraviolet Shielding ◽  
Shielding Effects

Abstract Unique technique is currently demonstrated for preparation of ultraviolet protective cotton fabrics with full shielding effect, via self-implantation of palladium nanopanciles. Palladium (Pd) nanopanciles were in-situ immobilized within native & cationized cotton using two different concentrations of palladium precursor (20 & 60 mM) under strong acidic (pH 2) and basic (pH 11.5) media. Cationization (50% and 100%) of cotton fabrics was performed in order to increase the accessibility of fabric for controllable implantation of palladium nanopanciles. Size distribution of palladium nanopanciles in supernatant solution was estimated via Transmission electron microscopy to be 3.2 nm. The estimated data showed that the sample prepared with the highest cationization percent and highest concentration of palladium precursor in strong alkaline medium exhibited the highest yellowness index, color strength and excellent ultraviolet shielding effects. The yellowness index was significantly increased from 15.67 for cationized cotton to 74.99 for the sample prepared with the highest cationization percent and highest concentration of Pd+2 in alkaline medium (Pd-CC (100)4). Tensile strength was insignificantly decreased from 93.2 MPa for cationized cotton to 84.5 MPa for Pd-CC (100)4. Ultraviolet shielding effect was superiorly enhanced with implantation of palladium nanopanciles. The UV protection factor (UPF) was also excellency increased from 1.3 (insufficient) for native cotton to 256.6 (excellent) for Pd-CC (100)4.

scholarly journals Potential Military Cotton Textiles by Carbon Quantum Dots

2021 ◽  
Author(s):  
Hossam E. Emam ◽  
Mahmoud El-Shahat ◽  
Mohamed S. Hasanin ◽  
Hanan B. Ahmed
Keyword(s):  
Staphylococcus Aureus ◽  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Cotton Fabrics ◽  
Protection Factor ◽  
Yellowness Index ◽  
E Coli ◽  
Microbial Inhibition ◽  
Blocking Activity ◽  
Fluorescence Peak

Abstract Owing to the sensitivity for color vicissitude by exposing to UV irradiation, manufacturing of fluorescent fabrics is widely demanded to be exploited in camping, sensing and military purposes. Pyrimidine based heterocycles were investigated with excellent pharmacological activity, however, their photoluminescence activity was never been investigated till now. The presented approach demonstrate a quite novel route for manufacturing of potential military textiles (fluorescent/UV-protective cotton fabrics with micobicide activity) via exploitation of carbon quantum dots (CQDs) nucleated from pyrimidine based heterocycle (4-(2,4-dichlorophenyl)-6-oxo-2-thioxohexahydropyrimidine-5-carbonitrile, Target Molecule, TM). The synthesized TM & CQDs were separately immobilized within both of native and cationized cotton fabrics to obtain TM@cotton, CQDs@cotton, TM@Q-cotton and CQDs@Q-cotton fabrics. The estimated yellowness index, intensity of the fluorescence peak, UV-blocking activity and microbicide action, were all followed the order of CQDs@Q-cotton > TM@Q-cotton > CQDs@cotton > TM @cotton. CQDs@Q-cotton showed quite good durability, as after 5 washings, yellowness index was diminished from 26.5 to only 20.3, florescence intensity for CQDs@Q-cotton was decreased from 540 nm to 340 nm and transmission percent was increased from 7 % to 10 %. Moreover, even after 10 washings, microbial inhibition (as a percent) against E. coli, Staphylococcus aureus and Candida albicans was estimated to 63 %, 68 % and 67 %, respectively, while, UV protection factor (UPF) was diminished from 38.2 (very good) to 21.5 (good). The presented unique route was succeeded for manufacturing of durable fluorescent textiles that could be superiorly applied as potential military textiles.

Growth of Nano-ZnO Particles in Cotton Fiber Interiors by In Situ Reaction

2015 ◽  
Vol 671 ◽  
pp. 285-292
Author(s):  
Wei Gou Dong ◽  
Qi Cui ◽  
Shu Dong Wang
Keyword(s):  
Low Temperature ◽  
Zno Nanoparticles ◽  
Cotton Fiber ◽  
Cell Walls ◽  
Cotton Fabrics ◽  
Cotton Fibers ◽  
Protection Factor ◽  
Uv Blocking ◽  
Zno Particles

ZnO nanoparticles were synthesized directly onto the surfaces, lumina, and cell walls of the cotton fibers at low temperature. Studies showed that the nanoZnO particles grown in cell walls of cotton fibers were globose particles with diameters around 40 nm, but those existing on the surfaces of cotton fibers were hexagonal sheeted crystalline solids and had higher crystallinity. Furthermore, UV-blocking characterization and the fastness to washing of the treated cotton fabrics were estimated. The results showed the treated fabrics provided an excellent UV protection factor rating of 50+ , and exhibited a high fastness to washing because nanoZnO particles were assembled in fibrous interiors .

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

1991 ◽  
Vol 49 ◽  
pp. 660-661
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
High Temperatures ◽  
Image Resolution ◽  
Atomic Processes ◽  
Crystal Surfaces ◽  
Beam Radiation ◽  
Surface Areas ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

In situ observations of electromigration induced void behavior

1995 ◽  
Vol 53 ◽  
pp. 244-245
Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden
Keyword(s):  
Electron Microscopy ◽  
Void Nucleation ◽  
Plan View ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Microelectronics Industry ◽  
In Situ Observations ◽  
Backscatter Electron Detector ◽  
Voltage Scanning

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

Dynamic studies of silicide-mediated crystallization of amorphous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1352-1353
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Metallic Phase ◽  
Single Crystal Substrate ◽  
Free Electrons ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

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