scholarly journals Impact of Acidity Profile on Nascent Polyaniline in the Modified Rapid Mixing Process—Material Electrical Conductivity and Morphological Study

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5108
Author(s):  
Sylwia Golba ◽  
Magdalena Popczyk ◽  
Seweryn Miga ◽  
Justyna Jurek-Suliga ◽  
Maciej Zubko ◽  
...  

Polyaniline (PANI) was synthesized chemically with the modified rapid mixing protocol in the presence of sulfuric acid of various concentrations. A two-step synthetic procedure was utilized maintaining low-temperature conditions. Application of the modified rapid mixing protocol allowed obtaining a material with local ordering. A higher concentration of acid allowed obtaining a higher yield of the reaction. Structural characterization performed with Fourier-transform infrared (FTIR) analysis showed the vibration bands characteristic of the formation of the emeraldine salt in both products. Ultraviolet–visible light (UV–Vis) spectroscopy was used for the polaronic band and the p–p* band determination. The absorption result served to estimate the average oxidation level of PANI by comparison of the ratio of the absorbance of the polaronic band to that of the π–π* transition. The absorbance ratio index was higher for PANI synthesized in a more acidic solution, which showed a higher doping level for this polymer. For final powder products, particle size distributions were also estimated, proving that PANI (5.0 M) is characterized by a larger number of small particles; however, these particles can more easily agglomerate and form larger structures. The X-ray diffraction (XRD) patterns revealed an equilibrium between the amorphous and semicrystalline phase in the doped PANI. A higher electrical conductivity value was measured for polymer synthesized in a higher acid concentration. The time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis showed that the molecular composition of the polymers was the same; hence, the difference in properties was a result of local ordering.

2001 ◽  
Vol 692 ◽  
Author(s):  
K. S. Huh ◽  
D. K. Hwang ◽  
K. H. Bang ◽  
M. K. Hong ◽  
D. H. Lee ◽  
...  

AbstractA series of ZnO thin films with various deposition temperatures were prepared on (100) GaAs substrates by radio-frequency magnetron sputtering using ZnO target. The ZnO films were studied by field emission scanning electron microscope(FESEM), x-ray diffraction(XRD), photoluminescence(PL), cathodoluminescence(CL), and Hall measurements. The structural, optical, and electrical properties of the films were discussed as a function of the deposition temperature. With increasing temperature, the compressive stress in the films was released and their crystalline and optical properties were improved. From the depth profile of As measured by secondary ion mass spectrometry(SIMS), As doping was confirmed, and, in order to activate As dopant atoms, post-annealing treatment was performed. After annealing treatment, electrical and optical properties of the films were changed.


Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 723 ◽  
Author(s):  
Anna Marzec ◽  
Bolesław Szadkowski

In this study, we produced a new organic-inorganic hybrid pigment based on a natural chromophore. Lawsone was selected as the active organic compound and incorporated into aluminum-magnesium hydroxycarbonate (LH). The hydroxynaphthoquinone derivative lawsone (Lawsonia inermis L.) is a naturally occurring dye, which is commonly used as a colorant because of its nontoxicity and biological functions. The structure and stability of the hybrid colorant were investigated using 27-Al solid-state nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), secondary ion mass spectrometry (TOF-SIMS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and UV-Vis spectroscopy. TOF-SIMS and 27Al NMR spectroscopy revealed interactions between the dye molecules and metal ions present in the LH host, confirming successful formation of an LH-based hybrid (LH/lawsone). In the next part of the study, we examined the effect of the hybrid pigment on the mechanical and thermal properties of ethylene-norbornene (EN) materials, as well as the aging resistance of the colored composites to irradiation across the full solar spectrum. Dynamic mechanical analysis (DMA) and the results of tensile break tests revealed that the EN+LH/lawsone composite had significantly better resistance to solar irradiation in comparison to EN and EN with an unmodified carrier.


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.


Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 190-196 ◽  
Author(s):  
V. A. Mu’izayanti ◽  
H. Sutrisno

Abstract The AgCl-sensitized TiO2 (TiO2@AgCl) has been prepared from the precursor of TiO2-rutile type which on its surface adsorb chloride anion (Cl-) and various amounts of silver using AgNO3 as starting material: AgNO3/(AgNO3+TiO2) mass ratio of 0.00, 1.14, 3.25, 6.38 and 10.32%. Reflux under alkaline condition was the employed technique. All samples were characterized by X-ray diffraction (XRD) and diffuse reflectance UV-vis spectroscopy. The sample without the addition of AgNO3 was analyzed by scanning electron microscope and surface area analyzer. The morphology of the sample showed a distribution of microspheres of approximately 0.5 to 1.0 µm and the specific surface area was 68 m2/g. XRD patterns indicated that the sample without the addition of AgNO3 contained two types of TiO2: rutile (major) and anatase (minor), whereas the samples with the addition of AgNO3 consisted of one phase of AgCl and two types of TiO2: rutile and anatase. The bandgaps of the samples were in the range of 2.97 to 3.24 eV, which were very close to the bandgap of intrinsic TiO2 powder. The presence of 0.8, 2.6 and 4.4 wt% of AgCl in each sample resulted in an additional bandgap in visible light region of 1.90, 1.94 and 2.26 eV, respectively, whereas the presence of 9.4 wt% of AgCl in the sample resulted in two bandgaps in visible light region of 1.98 and 1.88 eV.


2009 ◽  
Vol 289-292 ◽  
pp. 541-550 ◽  
Author(s):  
Jerzy Jedlinski ◽  
Zbigniew Żurek ◽  
Martah Homa ◽  
G. Smoła ◽  
J. Camra

The oxidation mechanism of FeCrAl (+RE), RE: reactive elements: Y and Hf) thin foils was studied at temperatures ranging from 1093 K to 1173 K in SO2+1%O2 atmosphere. Materials were subjected to isothermal and thermal cycling exposures as well as to the so-called two-stage-oxidation. In the latter, an oxygen isotope 18O2 was used as a tracer. Starting materials and scales were characterized using Grazing Angle X-Ray Diffraction (GA-XRD), EDX, SEM, XPS and High Spatial Resolution Secondary Ion Mass Spectrometry (HSR-SIMS). The obtained results showed within the studied range of exposure conditions the scales on all the studied alloys grow via outward mechanism typical for transient oxides and not for the -Al2O3 which is consistent with phase composition results and scale morphology and/or microstructure. It was also found that ‘as received’ foils are not bare metals but complex oxide-on-metal systems resulting from their manufacturing procedure. The obtained results are discussed in terms of the diffusion-related transport properties of the scale and of the scale phase composition.


2017 ◽  
Vol 751 ◽  
pp. 825-830 ◽  
Author(s):  
Phuri Kalnaowakul ◽  
Tonghathai Phairatana ◽  
Aphichart Rodchanarowan

In this study, the photocatalytic properties and morphology of TiO2, ZnO, Ag-graphene-zinc oxide (Ag-G-ZnO) and Ag-graphene-titanium dioxide (Ag-G-TiO2) nanocomposite were compared. The Ag-G-ZnO and Ag-G-TiO2 nanocomposite were successfully prepared by thermal decomposition of colloidal solution. These prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy and photocatalytic activities. The results from XRD patterns show that Ag-G-TiO2 composites and the Ag-G-ZnO nanocomposites were in the form of fcc and hcp crystal structure, respectively. The SEM images show that at calcination of 500 °C for 3 h, the composite thin film of Ag-G-ZnO and Ag-G-TiO2 were homogenous. In the case of the photocatalytic experiments using methylene blue dye (MB) under UV irradiation, the order of the photocatalytic activities from high to low performances are Ag-G-ZnO, Ag-G-TiO2, ZnO and TiO2, respectively.


1998 ◽  
Vol 537 ◽  
Author(s):  
M.D. McCluskey ◽  
L.T. Romano ◽  
B.S. Krusor ◽  
D. Hofstetter ◽  
D.P. Bour ◽  
...  

AbstractInterdiffusion of In and Ga is observed in InGaN multiple-quantum-well superlattices for annealing temperatures of 1250 to 1400°C. Hydrostatic pressures of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN and GaN. In as-grown material, x-ray diffraction spectra show InGaN superlattice peaks up to the fourth order. After annealing at 1400°C for 15 min, only the zero-order InGaN peak is observed, a result of compositional disordering of the superlattice. Composition profiles from secondary ion mass spectrometry indicate significant diffusion of Mg from the p-type GaN layer into the quantum well region. This Mg diffusion may lead to an enhancement of superlattice disordering. For annealing temperatures between 1250 and 1300°C, a blue shift of the InGaN spontaneous emission peak is observed, consistent with interdiffusion of In and Ga in the quantum-well region.


2015 ◽  
Vol 08 (03) ◽  
pp. 1540012 ◽  
Author(s):  
Jia-Hu Ouyang ◽  
Cheng Zhu ◽  
Zhan-Guo Liu ◽  
Zhe Ren ◽  
Lin Jing

( Nd 0.7 Yb 0.3)2 Zr 2 O 7 and (( Nd 0.7 Yb 0.3)1-x Sm x)2 Zr 2 O 7 (0 < x ≤ 0.25) ceramics have been synthesized by pressureless sintering by tailoring the chemical compositions. Microstructure and electrical conductivity of (( Nd 0.7 Yb 0.3)1-x Sm x)2 Zr 2 O 7 were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and AC impedance spectroscopy. ( Nd 0.7 Yb 0.3)2 Zr 2 O 7 ceramic exhibits a mixed crystal structure of defect fluorite and pyrochlore. After doping with Sm 3+ cations, the structure changes from a mixed type of ( Nd 0.7 Yb 0.3)2 Zr 2 O 7 to a single pyrochlore type of (( Nd 0.7 Yb 0.3)1-x Sm x)2 Zr 2 O 7, as the addition of Sm 3+ reduces the difference in ionic radius between Nd 3+ and Yb 3+. However, (( Nd 0.7 Yb 0.3)1-x Sm x)2 Zr 2 O 7 ceramics contain the localized short-range disorder despite the structural order overall in the pyrochlore. The measured total conductivities of (( Nd 0.7 Yb 0.3)1-x Sm x)2 Zr 2 O 7 obey the Arrhenius relation. Doping of Sm 3+ enhances the electrical conductivity of ( Nd 0.7 Yb 0.3)2 Zr 2 O 7 ceramic significantly, which is closely related to the variations in the concentration of oxygen vacancies at 48f sites, relatively low activation energy and high pre-exponential factor caused by the long-range order and short-range disorder.


2006 ◽  
Vol 70 (4) ◽  
pp. 405-418 ◽  
Author(s):  
F. Cámara ◽  
L. Ottolini ◽  
B. Devouard ◽  
L. A. J. Garvie ◽  
F. C. Hawthorne

AbstractSazhinite-(La) is a new mineral from the Aris phonolite, Windhoek, Namibia. It occurs in vesicles within the phonolite, together with other species crystallized from late-stage hydrothermal fluids: natrolite, aegirine, microcline, apophyllite, sphalerite, analcime, fluorite, villiaumite, hydroxylapatite, galena, makatite, quartz, eudialyte, kanemite, tuperssuatsiaite and korobitsynite. Sazhinite-(La) forms small euhedral crystals up to 1 mm long and 0.4 mm wide, elongated along [001] and flattened on (010), exhibiting the forms {h0l}, {100} and {001}. It has good cleavage parallel to {010} and {001}. Twinning was not observed. Crystals are brittle with a Mohs hardness of 3, creamy white with a white streak, vitreous to pearly lustre, and translucent to transparent. In plane-polarized light, crystals are colourless with a = Z, b = Y, c = X. It is biaxial positive with α = 1.524, β = 1.528, γ = 1.544, all ±0.002, 2Vz(obs) = 46(1)°, and 2Vz(calc.) = 53.6°.Sazhmite-(La) is orthorhombic Pmm2, a = 7.415(2), b = 15.515(3), c = 7.164(1) Å, and V = 824.2 Å3. One crystal was studied by X-ray diffraction, electron microprobe and secondary ion mass spectrometry (SIMS) microanalysis, leading to the average composition (Na2.87K0.02Sr0.01)Σ2.90 [La0.41Ce0.35Pr0.02Nd0.04(Sm,Gd,Dy,Er,Yb)Σ0.01Th0.09U0.01Y0.01Zr0.01Ca0.08Li0.01]Σ1.04 (S15.87S0.06B0.01) (O14.86F0.14).(H2O)2.Weighted full-matrix least-squares refinement on 3369 reflections yielded Rall = 3.8%. The structure is built of corrugated [Si6O15]6- layers linked by [7]-coordinated REE and R4+ cations. This framework leaves channels that contain three [5]- and [6]-coordinated Na cations per formula unit that compensate for the residual charge on the silicate layers. The SIMS analyses confirm a Na content of 3 atoms per formula unit, leading to an ideal formula of Na3LaSi6O15(H2O)2. The third Na atom is bonded to H2O groups and therefore the total content of both Na and H2O may be reduced to 2 and 1 per formula, respectively. The depletion in Na allows for the entrance of high-charge cations such as Th4+.


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