scholarly journals Enhanced Physical Absorption Properties of ZnO Nanorods by Electrostatic Self-Assembly with Reduced Graphene Oxide and Decorated with Silver and Copper Nanoparticles

2021 ◽  
Vol 19 (48) ◽  
pp. 66-78
Author(s):  
Lina Zeki Yahiya ◽  
Mohamed K. Dhahir
Keyword(s):  
Self Assembly ◽  
Low Cost ◽  
Zno Nanorods ◽  
Zinc Oxide Nanorods ◽  
Environmental Friendliness ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Oxide Nanorods ◽  
Scale Preparation

The preparation and characterization of innovative nanocomposites based on zinc oxide nanorods (ZNR) encapsulated by graphene (Gr) nanosheets and decorated with silver (Ag), and cupper (Cu) nanoparticles (NP) were studied. The prepared nanocomposites (ZNR@Gr/Cu-Ag) were examined by different techniques including Field Emission Scanning Electron Microscope (FESEM), Transmission electron microscopy (TEM), Atomic force microscopy (AFM), UV-Vis spectrophotometer and fluorescence spectroscopy. The results showed that the ZNR has been good cover by five layers of graphene and decorated with Ag and Cu NPs with particles size of about 10-15 nm. The ZNR@Gr/Cu-Ag nanocomposites exhibit high absorption behavior in ultraviolet (UV) region of spectrum. In comparison with ZNR, the ZNR@Gr/Cu-Ag nanocomposites reveal superior absorption in the entire region of 387–1000 nm. Moreover, the band gap decreases from 3.2 eV of ZNR to 1.2 eV for ZNR@Gr/Cu-Ag nanocomposites. Taking into account the superiority of ZNR@Gr/Cu-Ag nanocomposites in terms of easy fabrication, low cost method, and environmental friendliness which made it favorable for huge-scale preparation in many applications such as water splitting, sensor, solar cell, antibacterial and optoelectronic devices.

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.

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.

Structural Properties of Stannic Oxide Coated Aluminium-Doped Zinc Oxide Nanorods

2015 ◽  
Vol 1109 ◽  
pp. 476-480
Author(s):  
Ahmad Syakirin Ismail ◽  
Mohd Firdaus Malek ◽  
Muhammad Amir Ridhwan Abdullah ◽  
Mohamad Hafiz Mamat ◽  
M. Rusop
Keyword(s):  
Zinc Oxide ◽  
Structural Properties ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Oxide Coating ◽  
Zinc Oxide Nanorods ◽  
Stannic Oxide ◽  
Immersion Method ◽  
Force Microscopy ◽  
Atomic Force

Aluminium (Al) - doped zinc oxide (ZnO) nanorods was deposited using sol-gel immersion method. To study the effect of stannic oxide coating (SnO2) on the structural properties of the ZnO nanorods, SnO2with different layers were deposited on the top of ZnO nanorods, from 1 to 5 layers. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM), atomic force microscopy and x-ray diffraction (XRD). The analyses showed that by increasing the deposited layer, the surface roughness of the samples reduced and also reduced the porosity of the surface.

Silver Nanodisk: Synthesis, Characterization and Self-Assembly

2002 ◽  
Vol 740 ◽  
Author(s):  
Sihai Chen ◽  
Zhiyong Fan ◽  
David L. Carroll
Keyword(s):  
Self Assembly ◽  
Basal Plane ◽  
Cetyltrimethylammonium Bromide ◽  
Large Scale ◽  
Self Assembled Monolayer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Triangular Silver Nanoplates ◽  
Strong Surface

ABSTRACTA new form of silver nanostructured materials, a silver nanodisk, is generated by a solution-phase approach. In this method, two main steps are applied: the first is the generation of the truncated triangular silver nanoplates, which are obtained by seed-mediated growth of silver particles using cetyltrimethylammonium bromide (CTAB) as the soft templates. The second is the mild aging of the above triangular silver nanoplate solution at 40 °C to get the desired silver nanodisks. Transmission electron microscopy and atomic force microscopy studies show that the nanodisk has a thickness of the order of 20 – 30 nm, and a diameter around 60 nm. X-ray and electron diffraction analysis reveal that the nanodisk is single crystal and with its basal plane as (111) lattice plane. These nanodisks display a strong surface plasmon absorption band at 475 nm; this band can be continuously tuned within 420 nm to 560 nm through adjusting the aging time. The formation of self-assembled monolayer of CTAB on the basal plane is suggested to account for both the anisotropic growth from triangular nanoplates to nanodisks, and the formation of large-scale necklace-like structures.

scholarly journals Graphene Synthesis by Ultrasound Energy Assisted Exfoliation of Graphite in Various Solvents

2020 ◽  
Author(s):  
Betül Gürünlü ◽  
Çiğdem Taşdelen-Yücedağ ◽  
Mahmut Bayramoğlu
Keyword(s):  
Low Cost ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Graphene Synthesis ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ultrasound Energy ◽  
Size And Morphology

Liquid Phase Exfoliation (LPE) method has been gaining increasing interest by academic and industrial researchers due to its simplicity, low-cost, and scalability. High intensity ultrasound energy was exploited to transform graphite to graphene in the solvents of dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), and perchloric acid (PA) without any surfactants or ionic liquids. The crystal structure, number of layers, particle size, and morphology of the synthesized graphene samples were characterized by X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Ultraviolet visible (UV–vis) spectroscopy, Dynamic Light Scattering (DLS), and Transmission Electron Microscopy (TEM). XRD and AFM analyses indicated that G-DMSO and G-DMF have few layers and G-PA has multilayers. The layer numbers of G-DMSO, G-DMF, and G-PA were determined as 9, 10, and 21, respectively. By DLS analysis, the particle sizes of graphene samples were estimated in a few micrometers. TEM analyses showed that G-DMSO and G-DMF possess sheet-like fewer layers and also, G-PA has wrinkled and unordered multilayers.

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.

scholarly journals Photoluminescence of MoS2Prepared by Effective Grinding-Assisted Sonication Exfoliation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jing-Yuan Wu ◽  
Meng-Na Lin ◽  
Long-De Wang ◽  
Tong Zhang
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Sonication Time ◽  
Final Solution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Large Scale Preparation ◽  
Scale Preparation ◽  
Microscopic Techniques

Exfoliation of bulk molybdenum disulfide (MoS2) using sonication in appropriate solvent is a promising route to large-scale preparation of few-layered or monolayered crystals. Grinding-assisted sonication exfoliation was used for preparing monolayered MoS2nanosheets from natural mineral molybdenite. By controlling the sonication time, larger crystallites could be further exfoliated to smaller as well as thinner nanosheets without damaging their structures. The concentration of 1.6 mg mL−1of final solution could be achieved. Several microscopic techniques like scanning electron microscopy, transmission electron microscopy, and atomic force microscopy were employed to evaluate the exfoliation results. Strong photoluminescence with the peak centered at 440 nm was also observed in the resulting dispersion which included several small lateral-sized (~3 nm) nanostructures.

scholarly journals Membrane binding controls ordered self-assembly of animal septins

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Agata Szuba ◽  
Fouzia Bano ◽  
Gerard Castro Linares ◽  
Francois Iv ◽  
Manos Mavrakis ◽  
...  
Keyword(s):  
Self Assembly ◽  
Lipid Membranes ◽  
Electrostatic Interactions ◽  
Membrane Binding ◽  
Cytoskeletal Proteins ◽  
Double Layers ◽  
Cell Cortex ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Septins are conserved cytoskeletal proteins that regulate cell cortex mechanics. The mechanisms of their interactions with the plasma membrane remain poorly understood. Here we show by cell-free reconstitution that binding to flat lipid membranes requires electrostatic interactions of septins with anionic lipids and promotes the ordered self-assembly of fly septins into filamentous meshworks. Transmission electron microscopy reveals that both fly and mammalian septin hexamers form arrays of single and paired filaments. Atomic force microscopy and quartz crystal microbalance demonstrate that the fly filaments form mechanically rigid, 12 to 18 nm thick, double layers of septins. By contrast, C-terminally truncated septin mutants form 4 nm thin monolayers, indicating that stacking requires the C-terminal coiled coils on DSep2 and Pnut subunits. Our work shows that membrane binding is required for fly septins to form ordered arrays of single and paired filaments and provides new insights into the mechanisms by which septins may regulate cell surface mechanics.

Antibody-Mediated Self-Limiting Self-Assembly for Quantitative Analysis of Nanoparticle Surfaces by Atomic Force Microscopy

2011 ◽  
Vol 17 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Carly Lay A. Geronimo ◽  
Robert I. MacCuspie
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Lower Cost ◽  
Synthesis Method ◽  
Force Microscopy ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Imaging ◽  
Induced Aggregation

AbstractQuantification of very low density molecular coatings on large (60 nm) gold nanoparticles (AuNPs) is demonstrated via the use of antibody-mediated self-limiting self-assembly of small and large AuNPs into raspberry-like structures subsequently imaged by atomic force microscopy (AFM). AFM imaging is proposed as an automated, lower-cost, higher-throughput alternative to immunostaining and imaging by transmission electron microscopy. Synthesis of large AuNPs, containing one of three ligand molecules in one of three stoichiometries (1, 2, or 10 ligands per AuNP), and small probe AuNPs with one of three antibody molecules in a one antibody per AuNP ratio, enabled a range of predicted self-limiting self-assembled structures. A model predicting the probability of observing a given small to large AuNP ratio based on a topography measurement such as AFM is described, in which random orientational deposition is assumed and which accounts for the stochastic synthesis method of the library AuNPs with varied ligand ratios. Experimental data were found to agree very well with the predictive models when using an established AFM sample preparation method that avoids drying-induced aggregation.

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