scholarly journals Experimental techniques for the characterization of carbon nanoparticles – a brief overview

2014 ◽  
Vol 5 ◽  
pp. 1760-1766 ◽  
Author(s):  
Wojciech Kempiński ◽  
Szymon Łoś ◽  
Mateusz Kempiński ◽  
Damian Markowski

The review of four experimental methods: X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance and four-point electrical conductivity measurements is presented to characterize carbon nanoparticles. Two types of carbon nanoparticle systems are discussed: one comprising the powder of individual carbon nanoparticles and the second as a structurally interconnected nanoparticle matrix in the form of a fiber. X-ray diffraction and Raman spectroscopy reveal the atomic structure of the carbon nanoparticles and allow for observation of the changes in the quasi-graphitic ordering induced by ultrasonic irradiation and with the so-called quasi-high pressure effect under adsorption conditions. Structural changes have strong influence on the electronic properties, especially the localization of charge carriers within the nanoparticles, which can be observed with the EPR technique. This in turn can be well-correlated with the four-point electrical conductivity measurements which directly show the character of the charge carrier transport within the examined structures.

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1034
Author(s):  
Oladipo Folorunso ◽  
Yskandar Hamam ◽  
Rotimi Sadiku ◽  
Suprakas Sinha Ray ◽  
Neeraj Kumar

In this study, a hybrid of graphene nanoplatelets with a polypyrrole having 20 wt.% loading of carbon-black (HGPPy.CB20%), has been fabricated. The thermal stability, structural changes, morphology, and the electrical conductivity of the hybrids were investigated using thermogravimetric analyzer, differential scanning calorimeter, X-ray diffraction analyzer, scanning electron microscope, and laboratory electrical conductivity device. The morphology of the hybrid shows well dispersion of graphene nanoplatelets on the surface of the PPy.CB20% and the transformation of the gravel-like PPy.CB20% shape to compact spherical shape. Moreover, the hybrid’s electrical conductivity measurements showed percolation threshold at 0.15 wt.% of the graphene nanoplatelets content and the curve is non-linear. The electrical conductivity data were analyzed by comparing different existing models (Weber, Clingerman and Taherian). The results show that Taherian and Clingerman models, which consider the aspect ratio, roundness, wettability, filler electrical conductivity, surface interaction, and volume fractions, closely described the experimental data. From these results, it is evident that Taherian and Clingerman models can be modified for better prediction of the hybrids electrical conductivity measurements. In addition, this study shows that graphene nanoplatelets are essential and have a significant influence on the modification of PPy.CB20% for energy storage applications.


Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.


2013 ◽  
Vol 68 (10) ◽  
pp. 1103-1107 ◽  
Author(s):  
Heike Haller ◽  
Michael Hog ◽  
Franziska Scholz ◽  
Harald Scherer ◽  
Ingo Krossing ◽  
...  

[HMIM][Br9] ([HMIM]=1-hexyl-3-methylimidazolium) has been investigated by Raman spectroscopy, single-crystal X-ray diffraction and NMR spectroscopy. Conductivity measurements show a high electrical conductivity like other polybromides.


2020 ◽  
Author(s):  
Phil Keenan ◽  
Alaric smith ◽  
Peter Slater

<p>In this paper we examine the effects of doping phosphate into yttrium, ytterbium, and thulium doped BaPrO<sub>3</sub>. Through phosphate doping it is possible to achieve high levels of Y/Yb/Tm, and we show that it is possible to completely replace all the Pr with this co-doping strategy, albeit such phases contained small impurities. The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. Conductivity data indicated that these heavily Y/Yb/Tm doped samples, however, showed lower conductivities than reported for previously for low levels (10-20%) of Y/Yb doping. </p>


2020 ◽  
Author(s):  
Phil Keenan ◽  
Alaric smith ◽  
Peter Slater

<p>In this paper we examine the effects of doping phosphate into yttrium, ytterbium, and thulium doped BaPrO<sub>3</sub>. Through phosphate doping it is possible to achieve high levels of Y/Yb/Tm, and we show that it is possible to completely replace all the Pr with this co-doping strategy, albeit such phases contained small impurities. The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. Conductivity data indicated that these heavily Y/Yb/Tm doped samples, however, showed lower conductivities than reported for previously for low levels (10-20%) of Y/Yb doping. </p>


1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.


Author(s):  
E. López-Honorato ◽  
P. J. Meadows ◽  
J. Tan ◽  
Y. Xiang ◽  
P. Xiao

In this work we have deposited silicon carbide (SiC) at 1300°C with the addition of small amounts of propylene. The use of propylene and high concentrations of methyltrichlorosilane (9 vol %) allowed the deposition of superhard SiC coatings (42 GPa). The superhard SiC could result from the presence of a SiC–C solid solution, undetectable by X-ray diffraction but visible by Raman spectroscopy. Another sample obtained by the use of 50 vol % Argon, also showed the formation of SiC with good properties. The use of a flat substrate together with the particles showed the importance of carrying out the analysis on actual particles rather than in flat substrates. We show that it is possible to characterize the anisotropy of pyrolytic carbon by Raman spectroscopy.


2020 ◽  
Author(s):  
Sahar. Mokhtari ◽  
Anthony.W. Wren

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.


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