scholarly journals Modified Natural Rubber Induced Aqueous to Toluene Phase Transfer of Gold and Platinum Colloids

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Mohamad Abu Bakar ◽  
Jamil Ismail ◽  
Cheng Hoon Teoh ◽  
Wei Leng Tan ◽  
Noor Hana Hanif Abu Bakar
Keyword(s):  
Natural Rubber ◽  
Organic Phase ◽  
Self Assembly ◽  
Phase Transfer ◽  
Average Particle Size ◽  
Average Particle ◽  
Platinum Particles ◽  
Before And After ◽  
Free Metal

Citrate-stabilized gold and platinum particles were prepared in aqueous phase and transferred to toluene phase by employing 2-propanol as the transfer agent. It was found that the modified natural rubber (ENR) induced the phase transfer and assisted the dispersion of the citrate-free metal particles into the organic phase. The amounts of gold and platinum transferred are 93.4% and 86.1%, respectively. This phase transfer technique produced organosols of smaller particle sizes and narrower size distribution with self-assembly arrangements when compared to those prepared via the previous in situ preparations. The respective average particle size and standard deviation of gold before and after phase transfer were6.3±1.7 nm and7.2±1.3 nm, while for platinum they were4.0±0.7 nm and4.2±0.8 nm. The slight increase in the average sizes and overall size distributions in both metals after transfer was attributed to multiparticle aggregation in the organic phase.

scholarly journals Novel Fork Architectures of Ag2S Nanoparticles Synthesized through In Situ Self-Assembly inside Chitosan Matrix

Nano Hybrids ◽  
2012 ◽  
Vol 1 ◽  
pp. 23-43 ◽  
Author(s):  
Lubna Hashmi ◽  
Prabha Sana ◽  
M.M. Malik ◽  
A.H. Siddiqui ◽  
M.S. Qureshi
Keyword(s):  
Self Assembly ◽  
Average Particle Size ◽  
Visible Region ◽  
Optical Quality ◽  
Average Particle ◽  
Tem Analysis ◽  
Broad Absorption Band ◽  
Chitosan Matrix ◽  
Vis Spectroscopy

In a simple reaction between Silver nitrate and Thiourea under the presence of Chitosan, novel fork architectures of silver sulfide (Ag2S) were obtained through In-situ self-assembly of Ag2S nanoparticles inside Chitosan matrix in aqueous basic environment. Samples were characterized by SEM, TEM, XRD, FTIR, Raman Spectroscopy and UV-vis Spectroscopy. Average particle size was found to be 8 nm from TEM analysis. Formation of crystalline monoclinic α-Ag2S was confirmed by SAED and X-ray diffraction analysis. The experimental results show that the fork architectures of Ag2S can be obtained from Tape like assemblies of Ag2S nanoparticles at the later stage of their growth with temperature. Raman spectra confirm the incorporation of Ag2S nanoparticles inside Chitosan matrix. Multiple resonant Raman peaks indicates that the yielded Ag2S nanoparticles possess good optical quality and crystalinity. FTIR spectra indicates that the Ag + ion is coupled with the C=O bond of the Chitosan molecules through the electrostatic interaction. UV-vis absorption spectrum of the Ag2S Fork architectures has a broad absorption band in the UV to visible region, and the blue-shifting of the band is observed along with the presence of both direct and indirect band gap.

scholarly journals Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil

2021 ◽  
Vol 13 (15) ◽  
pp. 8122
Author(s):  
Shijie Tian ◽  
Weiqiang Tan ◽  
Xinyuan Wang ◽  
Tingting Li ◽  
Fanhao Song ◽  
...  
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Humic Acid ◽  
Forest Soil ◽  
Surface Activity ◽  
Self Assembly ◽  
Average Particle Size ◽  
Gaussian Model ◽  
Exponential Model ◽  
Average Particle

Surface activity of humic acid (HA) and its six sub-fractions isolated from forest soil were characterized by surface tension measurements, dynamic light scattering, and laser doppler electrophoresis. The surface tension of HA and its sub-fractions reduced from 72.4 mN·m−1 to 36.8 mN·m−1 in exponential model with the increasing concentration from 0 to 2000 mg·L−1. The critical micelle concentration (CMC) and Z-average particle size ranged from 216–1024 mg·L−1 and 108.2–186.9 nm for HA and its sub-fractions, respectively. The CMC have related with alkyl C, O-alkyl C, aromatic C, and carbonyl C (p < 0.05), respectively, and could be predicted with the multiple linear regression equation of CMC, CMC = 18896 − 6.9 × C-296 × alkyl C-331 × aromatic C-17019 × H/C + 4054 × HB/HI (p < 0.05). The maximum particle size was 5000 nm after filtered by a membrane with pore size of 450 nm, indicating HA and its sub-fractions could progressed self-assembly at pH 6.86. The aggregate sizes of number-base particle size distributions were mainly in six clusters including 2 ± 1 nm, 5 ± 2 nm, 10 ± 3 nm, 21 ± 8 nm, 40 ± 10 nm, and >50 nm analyzed by Gaussian model that maybe due to the inconsistency of the components and structures of the HA sub-fractions, requiring further study. It is significance to explore the surface activity of HA and its sub-fractions, which is helpful to clarify the environmental behavior of HA.

scholarly journals Effect of soil textural characteristics on longitudinal dispersion in saturated porous media

2021 ◽  
Vol 69 (2) ◽  
pp. 161-170
Author(s):  
Mojtaba G. Mahmoodlu ◽  
Amir Raoof ◽  
Martinus Th. van Genuchten
Keyword(s):  
Particle Size ◽  
Dispersion Coefficient ◽  
Average Particle Size ◽  
Longitudinal Dispersion ◽  
Average Particle ◽  
Sand Sample ◽  
Average Pore ◽  
Advection Dispersion ◽  
Strong Positive Relationship

Abstract This study focuses on the effects of soil textural heterogeneity on longitudinal dispersion under saturation conditions. A series of solute transport experiments were carried out using saturated soil columns packed with two filter sands and two mixtures of these sands, having d50 values of 95, 324, 402, and 480 µm, subjected to four different steady flow rates. Values of the dispersion coefficient (D) were estimated from observed in-situ distributions of calcium chlo-ride, injected as a short nonreactive tracer pulse, at four different locations (11, 18, 25, 36 cm). Analyses of the observed distributions in terms of the standard advection-dispersion equation (ADE) showed that D increased nonlinearly with travel distance and higher Peclet numbers+. The dispersion coefficient of sand sample S1 with its largest average particle size (d 50) was more affected by the average pore-water velocity than sample S4 having the smallest d 50. Results revealed that for a constant velocity, D values of sample S1 were much higher than those of sample S4, which had the smallest d 50. A correlation matrix of parameters controlling the dispersion coefficient showed a relatively strong positive relationship between D and the Peclet number. In contrast, almost no correlation was evident between D and porosity as well as grain size. The results obtained with the four sandy matrices were consistent and proved that the dispersion coefficient depends mainly on the particle size.

scholarly journals FORMULATION AND EVALUATION OF DOXORUBICIN CONTAINING NANOGELS FOR DELIVERY TO CANCER CELLS

2018 ◽  
Vol 8 (5) ◽  
pp. 178-183
Author(s):  
Manish Kumar ◽  
Hemant K. Sharma
Keyword(s):  
Average Particle Size ◽  
Gellan Gum ◽  
Cross Linking ◽  
Average Particle ◽  
Scanning Calorimetry ◽  
Green Method ◽  
X Ray ◽  
Oppositely Charged ◽  
Chemical Cross Linking

The objective of this study is to prepare nanogels were prepared via charged gellan gum. It was prepared by in situ cross linking reaction between two oppositely charged materials by green method without use of chemical cross linking agents. The prepared nanogels were characterized by Dynamic light scattering, scanning electron microscopy, differential scanning calorimetry and X- Ray diffractometry. The prepared formulation had average particle size of 226 nm with polydispersity index of 0.3. The doxorubicin loaded nanogel demonstrated sustained release for 20 h. The prepared nanogels were hemocompatible and cyctocompatible as revealed by hemocompatibility and MTT assay respectively. All results confirmed that these nanogels can be used for cancer treatment. Keywords: Nanogel, Chitosan, Gellan gum, Doxorubicin, Cancer.

scholarly journals Obtaining the conductive SnO2 films by chemical bath deposition method

2019 ◽  
Vol 60 (11) ◽  
pp. 1-10
Author(s):  
Vladislav I. Rogozin ◽  
◽  
Vyacheslav F. Markov ◽  
Larisa N. Maskaeva ◽  
Anastasia E. Krasovskaya ◽  
...  
Keyword(s):  
Tin Dioxide ◽  
Solid Phase ◽  
Average Particle Size ◽  
Ammonium Fluoride ◽  
Contact Layer ◽  
Average Particle ◽  
Solution Ph ◽  
Before And After ◽  
Initial Salt ◽  
Conductive Properties

Thanks to such unique properties as transparency and conductivity tin dioxide often utilize as transparent contact layer to produce displays, solar cells, and sensor devices. Hydrochemical method of deposition SnO2 films is a perspective due to its simplicity, and economical efficiency. The ionic equilibria analysis was carried out and the boundary conditions of Sn(OH)2 solid phase formation in the «Sn2+ – H2O – OH‾» system calculated. It was established, that tin(II) hydroxide may be obtain in the range 2 < pH < 12. Preliminary results allow to determinate an optimal mixture sourness interval 1 < pH < 5. Revealed, that the thickness of the Sn(OH)2 films strongly depends on the solution pH. Maximum value of 488 nm reached at pH = 8. Conductive SnO2 layers were obtained on a glass and sitall substrates with simultaneously presence of antimony chloride and ammonium fluoride followed by annealing in air. The thickness vs temperature and thickness vs tin initial salt concentration dependences were installed. The uniform tin hydroxide layers with a thickness of ~74 nm may be synthesized under pH = 2 conditions. By the electron microscopy method the average particle size was established changing from 200 to 400 nm for as-synthesized films, to ~20 nm for annealed which indicates the nanostructure nature of the films. The morphology, elemental composition and conductive properties of deposited films were investigated before and after heating stage. Studying the annealing temperature influence at the film resistance were identified a three temperature ranges within which the films sharply differ in their conductive properties, which is associated with phase and structural transformations in them. Shown, that the most conductive SnO2 films with the omic resistance 3-5 kOm/sm were obtained at the temperature range 620-870 K.

Electrochemical Self-Assembly of ZnO Nanosheetlike Structures

2014 ◽  
Vol 606 ◽  
pp. 3-7
Author(s):  
Lee Siang Chuah ◽  
S.Y. Chin ◽  
S.S. Tneh ◽  
M.A. Ahmad ◽  
S.K. Mohd Bakhori ◽  
...  
Keyword(s):  
Electrochemical Deposition ◽  
Self Assembly ◽  
Average Particle Size ◽  
Hexagonal Structure ◽  
Band Edge Emission ◽  
Average Particle ◽  
Exciton Transition ◽  
Xrd Diffraction ◽  
Current Densities ◽  
Scherrer Formula

ZnO nanosheetlike structures were synthesized on zinc (Zn) foil substrates by electrochemical deposition method in ZnCl2aqueous solutions at a temperature of 90 °C. In addition, the synthetic parameters in this work allow additional structural direction for ZnO nanoscaled structures. The morphology growth from smooth plane structures to nanosheet like structures could be accomplished by modifying the current densities of electrodeposition. In the photoluminescence (PL) spectra of the as-synthesized ZnO samples, typically there are few oxygen vacancies or interstitial Zn centers would be produced when the electrochemical deposition was performed out with a low current density. The UV peak is usually considered as the characteristic emission of ZnO nanosheetlike structures and attributed to the band edge emission or the exciton transition. All XRD diffraction peaks of ZnO nanosheetlike structures are shown in a good agreement with hexagonal structure. The average particle size was calculated using the Debye-Scherrer formula. ZnO nanosheetlike structures processed for various current densities have different size.

Polyaniline: Thin films and colloidal dispersions (IUPAC Technical Report)

2005 ◽  
Vol 77 (5) ◽  
pp. 815-826 ◽  
Author(s):  
Jaroslav Stejskal ◽  
Irina Sapurina
Keyword(s):  
Thin Films ◽  
Dispersion Polymerization ◽  
Average Particle Size ◽  
Colloidal Dispersions ◽  
Water Soluble ◽  
Average Particle ◽  
Water Soluble Polymer ◽  
Ammonium Peroxydisulfate ◽  
Technical Report

Several workers from various institutions in six countries have prepared thin films and colloidal polyaniline dispersions. The films were produced in situ on glass supports during the oxidation of anilinium chloride with ammonium peroxydisulfate in water. The average thickness of the films, assessed by optical absorption, was 125 ± 9 nm, and the conductivity of films was 2.6 ± 0.7 S cm–1. Films prepared in 1 mol l–1 HCl had a similar thickness, 109 ± 10 nm, but a higher conductivity, 18.8 ± 7.1 S cm–1. Colloidal polyaniline particles stabilized with a water-soluble polymer, poly(N-vinylpyrrolidone) [poly(1-vinylpyrrolidin-2-one)], have been prepared by dispersion polymerization. The average particle size, 241 ± 50 nm, and polydispersity, 0.26 ± 0.12, have been determined by dynamic light scattering. The preparation of these two supramolecular polyaniline forms was found to be well reproducible.

Impacts of Acid Treatment on the Characteristics of Native Corn Starch Granules

2011 ◽  
Vol 221 ◽  
pp. 72-77 ◽  
Author(s):  
Xin Jin ◽  
Shuan Qing Hou ◽  
Xiao Xu Sha ◽  
Liang Yu
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Acid Treatment ◽  
Corn Starch ◽  
Average Particle Size ◽  
Peak Temperature ◽  
Average Particle ◽  
Starch Granules ◽  
Acid Modification ◽  
Before And After

Native corn starches were acid-treated at 53 °C for hours in HCl aqueous solution. The peak temperature (Tp) and heat of gelatinization (ΔHgel) before and after treatments were determined. The average particle size, TG and viscosity were measured. The results showed that the viscosity of corn starch decreased from 630mPa to 4.6mPa after acid treatment for 6h. The average particle size decreased and ΔHgel decreased obviously after acid modification.

Fabrication and Properties of Self-Assembled Nanosized Magnetic Particles

2001 ◽  
Vol 707 ◽  
Author(s):  
G. Salazar-Alvarez ◽  
M. Mikhailova ◽  
M. Toprak ◽  
Y. Zhang ◽  
M. Muhammed
Keyword(s):  
Self Assembly ◽  
Magnetic Particles ◽  
Average Particle Size ◽  
The Self ◽  
Average Particle ◽  
Shell Nanoparticles ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Self Assembled ◽  
Core Shell Nanoparticles

ABSTRACTThe synthesis and characterisation of gold-coated cobalt nanoparticles, as well as their chemically- and magnetically-induced self-organisation have been studied. Metallic core-shell nanoparticles were prepared using two different experimental techniques: bulk reductive precipitation, with average particles size ∼15 nm, and microemulsion confining method, with average particle size of ∼6 nm. The self-assembly of prepared nanoparticles on flat substrates was achieved by derivatising the substrate and particle surfaces with bifunctional organic molecules that attaches to both particles and substrates. Examination of the self-assembled systems was carried out by a number of characterisation techniques including transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-VIS), and atomic force microscopy (AFM).

An ultrastructural method for the study of cell viability using ruthenium red

1978 ◽  
Vol 36 (2) ◽  
pp. 304-305
Author(s):  
Babaï Féridoun
Keyword(s):  
Electron Microscopy ◽  
Cell Culture ◽  
Average Particle Size ◽  
Ruthenium Red ◽  
Average Particle ◽  
Cell Coat ◽  
Novikoff Hepatoma ◽  
Viable Cells ◽  
Ultrastructural Method

Ruthenium Red (RR), a colored inorganic dye, has been used in electron microscopy to stain and visualize the glycoproteins of the cell coat. It has an average particle size of 1.13 nm and does not seem to penetrate the intact plasma membrane. Consequently the cytoplasmic and nuclear components of viable cells are not stained with this electron-opaque marker.We have used these properties of RR to develop a method for the study of abnormal permeability of damaged cell membrane and to stain nonviable cells. Under certain conditions, RR stains the cytoplasm of damaged cells in suspension (Figs. 1,2) or in culture in situ (Figs. 3-5). The stained (permeable) cells are easily visualized under the light and electron microscope.Cell suspension of an ascitic Novikoff Hepatoma and cell culture from a Rhabdomyosarcoma were utilized for this study.

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