Hybrid Nanoparticles Prepared by In-situ and Post-synthetic Surface Modification of Lanthanide-Based Nanoparticles with Phosphonic Acid Derivatives

2007 ◽  
Vol 1007 ◽  
Author(s):  
Christoph Rill ◽  
Sorin Ivanovici ◽  
Guido Kickelbick
Keyword(s):  
Surface Modification ◽  
Phosphonic Acid ◽  
Hybrid Nanoparticles ◽  
Phosphonic Acids ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Separate Step ◽  
20 Nm

ABSTRACTThe use of various phosphonic acid derivatives – some of which contain polymerizable groups – as surface modifying agents for nanoparticles was studied both in-situ during the synthesis of lanthanide-based (Ln = Nd, Eu, Yb) nanoparticles at room temperature as well as in a separate step after the particle preparation by a hydrothermal method. In the single-pot in-situ method the phosphonic acid esters served as growth-limiting agent during particle formation leading to small nanoparticles with a size of only a few nanometers as determined by dynamic light scattering as well as transmission electron and atomic force microscopy. Free phosphonic acids as well as their silyl esters were used to modify the hydrothermally prepared neodymium hydroxide nanorods which had diameters of approx. 20 nm and a length ranging up to a few micrometers. The surface modification was confirmed by infrared spectroscopy and thermogravimetric analysis.

(G03 Best Paper Award Winner) Analysis of Sn Behavior During Ni/GeSn Solid-State Reaction by Correlated X-ray Diffraction, Atomic Force Microscopy, and Ex-situ/In-situ Transmission Electron Microscopy

2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ex Situ ◽  
Paper Award ◽  
X Ray Diffraction ◽  
Award Winner ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Characterization and Optimization of The Tco/a-Si:H(,B) Interface for Solar Cells by In-Situ Ellipsometry and Sims/XPS Depth Profiling

1994 ◽  
Vol 336 ◽  
Author(s):  
H.N. Wanka ◽  
E. Lotter ◽  
M.B. Schubert
Keyword(s):  
Solar Cells ◽  
Light Trapping ◽  
Hydrogen Plasma ◽  
Depth Profiling ◽  
Trapping Efficiency ◽  
Force Microscopy ◽  
Hydrogen Plasmas ◽  
Atomic Force ◽  
20 Nm

ABSTRACTThe chemical reactions at the surface of transparent conductive oxides (SnO2, ITO and ZnO) have been studied in silane and hydrogen plasmas by in-situ ellipsometry and by SIMS as well as XPS depth profiling. SIMS and XPS of the interface reveal an increasing amount of metallic phases upon lowering a-Si:H growth rates (controlled by plasma power), indicating that the ion and radical impact is more than compensated by protecting the surface by a rapidly growing a-Si:H film. Hence, optical transmission of TCO films as well as the efficiency of solar cells can be improved if the first few nanometers of the p-layer are grown at higher rates. Comparing a-Si:H deposition on top of different TCOs, reduction effects on ITO and SnO2 have been detected whereas ZnO appeared to be chemically stable. Therefore an additional shielding of the SnO2 surface by a thin ZnO layer has been investigated in greater detail. Small amounts of H are detected close to the ZnO surface by SIMS after hydrogen plasma treatment, but no significant changes occur to the optical and electrical properties. In-situ ellipsometry indicates that a ZnO layer as thin as 20 nm completely protects SnO2 from being reduced to metallic phases. This provides for shielding of textured TCOs, and hence rising solar cell efficiencies, too. Regarding light trapping efficiency we additionally investigated the smoothing of initial TCO texture when growing a-Si:H on top by combining atomic force microscopy and spectroscopie ellipsometry.

Mechanical Stress, Grain-boundary Relaxation, and Oxidation of Sputtered CuNi(Mn) Films

1999 ◽  
Vol 14 (4) ◽  
pp. 1286-1294 ◽  
Author(s):  
W. Brückner ◽  
W. Pitschke ◽  
S. Baunack ◽  
J. Thomas
Keyword(s):  
Grain Boundary ◽  
Microstructural Characterization ◽  
Excess Vacancy ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Boundary Relaxation ◽  
20 Nm ◽  
Atomic Rearrangement

This paper focuses on understanding stress development in CuNi42Mn1 thin films during annealing in Ar. In addition to stress-temperature measurements, resistance-temperature investigations and chemical and microstructural characterization by Auger electron spectroscopy, scanning and transmission electron microscopy, x-ray diffraction, and atomic force microscopy were also carried out. The films are polycrystalline with a grain size of 20 nm up to 450 °C. To explain the stress evolution above 120 °C, atomic rearrangement (excess-vacancy annihilation, grain-boundary relaxation, and shrinkage of grain-boundary voids) and oxidation were considered. Grain-boundary relaxation was found to be the dominating process up to 250–300 °C. A sharp transition from compressive to tensile stress between 300 and 380 °C is explained by the formation of a NiO surface layer due to reaction with the remaining oxygen in the Ar atmosphere. This oxidation is masking the inherent structural relaxation above 300 °C.

Fabrication of Two-Dimensional PEDOT:PSS Nanosheets Through In Situ Formed Complexes

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550011 ◽  
Author(s):  
Kun Zhang ◽  
Shiren Wang
Keyword(s):  
In Situ Polymerization ◽  
Molecular Complexes ◽  
Water Soluble ◽  
Strong Interactions ◽  
Two Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ftir Characterization ◽  
Transmission Electron

This paper presents a simple and effective method to fabricate water-soluble two-dimensional (2D) conductive poly(3,4-ethylenedioxythiophene):poly (sodium 4-styrenesulfonate) (PEDOT:PSS) nanosheets. Linear PSS is water-soluble and exhibits a quasi 1D structure in the dilute solution. Addition of 3,4-ethylenedioxythiophene (EDOT) monomers into acidic solutions would form 2D molecular complexes due to charge attraction. In situ polymerization of the ethylenedioxythiophene monomers produces 2D poly EDOT nanosheets. Both transmission electron microscopy and atomic force microscopy characterizations have confirmed the 2D polymeric nanosheets. Further Fourier transform infrared (FTIR) characterization also validated that the 2D nanosheet is composed of EDOT-based units and Raman spectroscopy indicated the strong interactions between ethylenedioxythiophene units in the 2D nanostructures. The electrical conductivity is measured to as high as 551.58 S/m for the thin film of as-produced 2D PEDOT:PSS nanosheets.

Growth of Epitaxial 2H-silicon Carbide by Pulsed Laser Deposition

1994 ◽  
Vol 339 ◽  
Author(s):  
Mark A. Stan ◽  
Martin O. Patton ◽  
Hemasiri K. M. Vithana ◽  
David L. Johnson ◽  
Joseph D. Warner ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Average Diameter ◽  
Laser Deposition ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Columnar Grains ◽  
20 Nm ◽  
Heater Plate

ABSTRACTSilicon carbide films have been grown on 6H-SiC (0001) and Si (001) wafers by laser ablation using an excimer laser. The films were deposited at heater plate temperatures between 970° C to 1270° C. Film composition, morphology and polytypism were determined by Auger electron spectroscopy, atomic force microscopy and high resolution transmission electron microscopy (TEM). In the course of these experiments growth of 2H-SiC on 6H-SiC was observed at the highest heater plate temperatures. Cross-sectional TEM images clearly show the symmetry of a film grown at 1270° C as c-axis oriented 2H-SiC containing columnar grains with average diameter of 20 nm and length of 100 nm.

scholarly journals Cell-wall-deficient Bacteria in Oral Biofilm: Association with Periodontitis

2020 ◽  
Author(s):  
Francesco Germano ◽  
Davide Testi ◽  
Luisa Campagnolo ◽  
Manuel Scimeca ◽  
Claudio Arcuri
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Chronic Periodontitis ◽  
Aggressive Periodontitis ◽  
Periodontal Pathogens ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Polymerase Chain

AbstractCell-wall-deficient bacteria are those that lack cell walls and live in a pleomorphic state. The genus Mycoplasma and L-form bacteria are both members of this group. The aim of this study was to search cell-wall-deficient bacteria in periodontal biofilm and link their presence to periodontal disease. Eighty-nine individuals were recruited and divided into three groups: periodontally healthy individuals, individuals with chronic periodontitis, and those with aggressive periodontitis. The presence of cell-wall-deficient bacteria was detected in freshly collected biofilm by light microscopy, transmission electron microscopy (TEM) with and without electron microscopy in situ hybridization, atomic force microscopy and DNA stain (Hoechst). A new dichotomic index of classification for prevalence and morphologic variants was developed to classify cell-wall-deficient bacteria in periodontal biofilm. Cell-wall-deficient bacteria were found in periodontal biofilm and classified into Protoplastic, Everted, Filament and Intracellular forms, the last one mainly associated with aggressive periodontitis. We also assessed the prevalence of periodontopathic bacteria by means of polymerase chain-reaction (PCR) and found no clear, statistically significant, correlation among periodontal pathogens tested (except T. denticola) that allowed individuals with chronic periodontitis to be distinguished from those with aggressive periodontitis. Association between cell-wall-deficient bacteria and periodontal condition was: periodontally healthy, 3.3% (1/30); individuals with chronic periodontitis, 30.6% (11/36); and those with aggressive periodontitis, 100% (23/23). Cell-wall-deficient bacteria were detected in periodontal biofilm and linked to aggressive periodontitis.

scholarly journals Characterization of a Novel Nanocomposite Film Based on Functionalized Chitosan–Pt–Fe3O4 Hybrid Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1275
Author(s):  
Sangeeta Kumari ◽  
Raj Pal Singh ◽  
Nayaku N. Chavan ◽  
Shivendra V. Sahi ◽  
Nilesh Sharma
Keyword(s):  
Nanocomposite Film ◽  
Biomedical Applications ◽  
Physical Property Measurement System ◽  
Physical Property ◽  
Nanocomposite Films ◽  
Hybrid Nanoparticles ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

The development of organic—inorganic hybrids or nanocomposite films is increasingly becoming attractive in light of their emerging applications. This research focuses on the formation of a unique nanocomposite film with enhanced elasticity suitable for many biomedical applications. The physical property measurement system and transmission electron microscopy were used to analyze Pt–Fe3O4 hybrid nanoparticles. These nanohybrids exhibited magnetic effects. They were further exploited to prepare the nanocomposite films in conjunction with a chitosan-g–glycolic acid organic fraction. The nanocomposite films were then examined using standard techniques: thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and atomic force microscopy. Tensile strength testing demonstrated a significantly greater elastic strength of these nanocomposite films than pure chitosan films. The water absorption behavior of the nanocomposites was evaluated by measuring swelling degree. These nanocomposites were observed to have substantially improved physical properties. Such novel nanocomposites can be extended to various biomedical applications, which include drug delivery and tissue engineering.

scholarly journals Cell-Wall-Deficient Bacteria in Oral Biofilm: Association with Periodontitis

2020 ◽  
pp. 1-14
Author(s):  
Francesco Germano ◽  
Francesco Germano ◽  
Davide Testi ◽  
Luisa Campagnolo ◽  
Manuel Scimeca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Chronic Periodontitis ◽  
Aggressive Periodontitis ◽  
Periodontal Pathogens ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Polymerase Chain

Cell-wall-deficient bacteria are those that lack cell walls and live in a pleomorphic state. The genus Mycoplasma and L-form bacteria are both members of this group. The aim of this study was to search cellwall-deficient bacteria in periodontal biofilm and link their presence to periodontal disease. Eighty-nine individuals were recruited and divided into three groups: periodontally healthy individuals, individuals with chronic periodontitis, and those with aggressive periodontitis. The presence of cell-wall-deficient bacteria was detected in freshly collected biofilm by light microscopy, transmission electron microscopy (TEM) with and without electron microscopy in situ hybridization, atomic force microscopy and DNA stain (Hoechst). A new dichotomic index of classification for prevalence and morphologic variants was developed to classify cell-wall-deficient bacteria in periodontal biofilm. Cell-wall-deficient bacteria were found in periodontal biofilm and classified into protoplastic, everted, filament and intracellular forms, the last one mainly associated with aggressive periodontitis. We also assessed the prevalence of periodontopathic bacteria by means of polymerase chain-reaction (PCR) and found no clear, statistically significant, correlation among periodontal pathogens tested (except T. denticola) that allowed individuals with chronic periodontitis to be distinguished from those with aggressive periodontitis. Association between cell-walldeficient bacteria and periodontal condition was: periodontally healthy, 3.3% (1/30); individuals with chronic periodontitis, 30.6% (11/36); and those with aggressive periodontitis, 100% (23/23). Cell-walldeficient bacteria were detected in periodontal biofilm and linked to aggressive periodontitis.

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