scholarly journals PAN Nanofibers Reinforced with MMT/GO Hybrid Nanofillers

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Qingqing Wang ◽  
Guohui Li ◽  
Jinning Zhang ◽  
Fenglin Huang ◽  
Keyu Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Self Assembly ◽  
Decomposition Temperature ◽  
Electrospinning Process ◽  
Test Machine ◽  
Force Microscopy ◽  
Noticeable Increase ◽  
Atomic Force ◽  
Transmission Electron

Single component nanofiller has shown some limitations in its performance, which can be overcome by hybrid nanofillers with two different components. In this work, montmorillonite (MMT)/graphene oxide (GO) hybrid nanofillers were formed by self-assembly and then incorporated into the polyacrylonitrile (PAN) nanofibers by electrospinning process. X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM) were utilized to analyze the structures of MMT/GO hybrid nanofillers. And the effects of MMT/GO hybrid nanofillers on the morphology, thermal stability, and mechanical properties of PAN/MMT/GO composite nanofibrous membrane were examined by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and tensile test machine, respectively. The incorporation of MMT/GO hybrid nanofillers into PAN nanofibers showed a noticeable increase up to 30°C for the onset decomposition temperature and 1.32 times larger tensile strength than the pure PAN, indicating that the hybrid nanofiller is a promising candidate in improving thermal and mechanical properties of polymers.

scholarly journals Morphology of Ethylene/1-Octene Copolymers and Their Blends with High Density Polythylene: A Microscopic Evaluation

2013 ◽  
Vol 30 ◽  
pp. 5-12 ◽  
Author(s):  
Rameshwar Adhikari
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Chemical Society ◽  
High Density ◽  
Force Microscopy ◽  
Strain Behavior ◽  
Atomic Force ◽  
Transmission Electron ◽  
Microscopic Evaluation ◽  
Wide Range

The investigation into morphology formation in ethylene/1-octene copolymers (EOCs) comprising variable 1-octene content and their blends with high density polyethylene (HDPE) and hence their tensile mechanical properties have been reported. The morphological analysis by means of atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed the macrophase separation of the components in the blends. In contrast to well defined spherulitic morphology and lamellar structure of the HDPE, the EOCs exhibited progressively distorted lamellar morphology with increasing 1-octene content. At high 1-octene content, the EOC samples possessed the ‘worm-like’ crystals, which resemble the ‘fringed micelles’ discussed in the literature. The blends allow a balance of mechanical properties (stiffness and toughness) over a wide range as shown by tensile stress strain behavior of the blends.DOI: http://dx.doi.org/10.3126/jncs.v30i0.9329Journal of Nepal Chemical Society Vol. 30, 2012 Page: 5-12 Uploaded date: 12/16/2013 

scholarly journals Nanohydrogels Based on Self-Assembly of Cationic Pullulan and Anionic Dextran Derivatives for Efficient Delivery of Piroxicam

Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 622 ◽  
Author(s):  
Dorota Lachowicz ◽  
Przemyslaw Mielczarek ◽  
Roma Wirecka ◽  
Katarzyna Berent ◽  
Anna Karewicz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Dextran Sulfate ◽  
Force Microscopy ◽  
Grafting Reaction ◽  
Atomic Force ◽  
Transmission Electron ◽  
Efficient Delivery ◽  
Model Drug

A cationic derivative of pullulan was obtained by grafting reaction and used together with dextran sulfate to form polysaccharide-based nanohydrogel cross-linked via electrostatic interactions between polyions. Due to the polycation-polyanion interactions nanohydrogel particles were formed instantly and spontaneously in water. The nanoparticles were colloidally stable and their size and surface charge could be controlled by the polycation/polyanion ratio. The morphology of the obtained particles was visualized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The resulting structures were spherical, with hydrodynamic diameters in the range of 100–150 nm. The binding constant (Ka) of a model drug, piroxicam, to the cationic pullulan (C-PUL) was determined by spectrophotometric measurements. The value of Ka was calculated according to the Benesi—Hildebrand equation to be (3.6 ± 0.2) × 103 M−1. After binding to cationic pullulan, piroxicam was effectively entrapped inside the nanohydrogel particles and released in a controlled way. The obtained system was efficiently taken up by cells and was shown to be biocompatible.

Synthesis of polystyrene-grafted carbon nanocapsules

2007 ◽  
Vol 22 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Hsuan-Ming Huang ◽  
Hung-Chieh Tsai ◽  
I-Chun Liu ◽  
Raymond Chien-Chao Tsiang
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Polymeric Composite ◽  
Decomposition Temperature ◽  
Polymeric Composite Material ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Carbon Nanocapsules

A novel polymeric composite material, polystyrene (PS)-grafted carbon nanocapsules (CNCs), has been prepared. sec-butyllithium was first used to introduce negative charges on CNCs, and these CNC carbanions acted then as initiators for anionic polymerization of styrene. Based on a weight loss at the decomposition temperature of the butyl groups, the quantity of the butyls attached to the CNC surface was determined as 1.18 wt%, corresponding to 0.25 mol% initiator per mol of carbon atom on the CNC surface. Furthermore, the decomposition temperature of butylated CNCs was lower than that of the pristine CNCs by nearly 200 °C. The polystyrene content in our PS-grafted CNC sample was approximately 20%, and the molecular weight of the grafted PS on the surface of CNCs was calculated as 1200 gmol−1. Compared with the molecular weight of the ungrafted PS, the molecular weight of grafted PS was lower, thus indicating rates of initiation and/or propagation for CNC-bound carbanions lower than those of the free sec-butyllithium. The PS-grafted CNCs had good dispersion in toluene, tetrahydrofuran, cyclohexane, and other common organic solvents in which polystyrene was dissolvable and thus indicated good compatibility when further blended with other styrenic polymers. The PS-grafted CNCs were characterized and examined by Fourier transform infrared, thermogravimetric analysis, atomic force microscopy, differential scanning calorimetry, ultraviolet-visible spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electron microscopy images indicated that the PS-grafted CNCs were homogeneous composites containing uniform polymer/CNC ratios.

Ionic self-assembly of porphyrin nanostructures on the surface of charge-altered track-etched membranes

2010 ◽  
Vol 14 (05) ◽  
pp. 446-451 ◽  
Author(s):  
Nametso Mongwaketsi ◽  
Patrick G. Ndungu ◽  
Alexander Nechaev ◽  
Malik Maaza ◽  
Raymond Sparrow
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Membrane Pore ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Self Assembled ◽  
Track Etched Membrane ◽  
Positively Charged

Track-etched polymer membranes are typically used as templates in the synthesis of various nanowires or nanotubes arrays. The unique advantages of track-etched membranes, such as uniform pore structure, excellent porosity, easily tailored pore sizes, and a well characterized surface chemistry, may find use in self-assembly strategies where colloidal nanostructures can be tethered to a suitable substrate to produce devices of interest. Meso-tetrakis(4-phenylsulfonicacid)porphyrin dihydrochloride and Sn(IV) tetrakis(4-pyridyl)porphyrin were used to synthesize ionic self-assembled porphyrin nanorods. The track-etched membranes surface charge was changed from negative to positive using polyethyleneimine. The porphyrin nanorods were either filtered through or self-assembled onto the surface of track-etched membranes. Comparisons were made with track-etched membranes modified with, and without, polyethyleneimine. Assembly of the porphyrin nanotubes only occurred on the surface of positively charged track-etched membranes, and filtration of the porphyrin nanorods produced a mesh-like structure on the surface of the membrane irrespective of the track-etched membrane pore diameter. In each case the characteristic absorbance profiles of the porphyrin nanorods was maintained. Transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and UV-vis spectroscopy were used to characterize the various systems.

Fluorescent Rosette Nanotubes from the C-analogue of the Guanine–Cytosine (G∧C) Motif

2015 ◽  
Vol 1796 ◽  
pp. 1-6 ◽  
Author(s):  
Belete Legesse ◽  
Jae-Young Cho ◽  
Rachel L. Beingessner ◽  
Takeshi Yamazaki ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Visible Spectroscopy ◽  
Fluorescent Properties ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Atomic Force ◽  
Transmission Electron ◽  
Uv Visible

ABSTRACTRosette nanotubes (RNTs) are tubular architectures generated through the hierarchical self-assembly of the guanine-cytosine (G∧C) motif 1 or 2 (Figure 1). Motif 2 differs from 1 by the substitution at the N-atom in the G-ring with a C-atom as shown in red. In this paper, we prepare a new tricyclic G∧C base 3 from a functionalized derivative of 2 and demonstrate its self-assembly into fluorescent helical RNTs in N,N-dimethylformamide (DMF). The self-assembly and fluorescent properties of RNTs 3 were established using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV-visible spectroscopy.

Combinatorial Approach to Materials Fabrication from Higher Hierarchies of Rosette Nanotubes

2007 ◽  
Vol 1057 ◽  
Author(s):  
Grigory Tikhomirov ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Combinatorial Approach ◽  
X Ray ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Self Assembling ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTThe self-assembly of six self-complimentary Guanine – Cytosine hybrid heterocycles bearing hydrophobic substituents has been studied using combinatorial approach in eight solvents under different conditions. The parameters that were varied include: the structure of the self-assembling module, its concentration, the solvent, temperature, and time of self-assembly. scanning electron microscopy (SEM) was used as a screening tool. A wide variety of interesting morphologies was found. The most interesting structures were studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray powder diffraction (XRD).

scholarly journals Corrosion Behavior and Mechanical Properties of a Nanocomposite Superhydrophobic Coating

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Nanocomposite Coating ◽  
Superhydrophobic Coating ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images ◽  
Scanning Electron

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

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