scholarly journals Synthesis of Colloidal Au Nanoparticles through Ultrasonic Spray Pyrolysis and Their Use in the Preparation of Polyacrylate-AuNPs’ Composites

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3775 ◽  
Author(s):  
Doris Golub ◽  
Andrej Ivanič ◽  
Peter Majerič ◽  
Hanuma Reddy Tiyyagura ◽  
Ivan Anžel ◽  
...  

Colloidal gold nanoparticles (AuNPs) were prepared from two different liquid precursors (gold (III) acetate and gold (III) chloride), using the Ultrasonic Spray Pyrolysis (USP) process. The STEM characterisation showed that the AuNPs from gold chloride are spherical, with average diameters of 57.2 and 69.4 nm, while the AuNPs from gold acetate are ellipsoidal, with average diameters of 84.2 and 134.3 nm, according to Dynamic Light Scattering (DLS) measurements. UV/VIS spectroscopy revealed the maximum absorbance band of AuNPs between 532 and 560 nm, which indicates a stable state. Colloidal AuNPs were used as starting material and were mixed together with acrylic acid (AA) and acrylamide (Am) for the free radical polymerization of polyacrylate-AuNPs’ composites, with the purpose of using them for temporary cavity fillings in the dental industry. SEM characterisation of polyacrylate-AuNPs’ composites revealed a uniform distribution of AuNPs through the polymer matrix, revealing that the AuNPs remained stable during the polymerization process. The density measurements revealed that colloidal AuNPs increase the densities of the prepared polyacrylate-AuNPs’ composites; the densities were increased up to 40% in comparison with the densities of the control samples. A compressive test showed that polyacrylate-AuNPs’ composites exhibited lower compressive strength compared to the control samples, while their toughness increased. At 50% compression deformation some of the samples fracture, suggesting that incorporation of colloidal AuNPs do not improve their compressive strength, but increase their toughness significantly. This increased toughness is the measured property which makes prepared polyacrylate-AuNPs potentially useful in dentistry.

2020 ◽  
Vol 63 ◽  
pp. 10-30
Author(s):  
Sabrina Iaiche ◽  
Chahra Boukaous ◽  
David Alamarguy ◽  
Abdelkader Djelloul ◽  
Djamel Hamana

A complex ZnO/ZnAl2O4 heterostructures thin films on glass and Si (111) substrates have been successively obtained by a soft ultrasonic spray pyrolysis (USP) method deposition using the Zn/Al molar ratios concentrations of 0.07/0.13 and 0.1/0.1, respectively. According to (XRD) an ordered zinc oxide (ZnO) and zinc aluminate (ZnAl2O4) structures deposited onto glass from the air annealing at 500 °C during 2 hours was observed and confirmed by the (EDX), (FTIR) and Raman spectroscopy techniques. The estimated crystallites size and stress values of ZnO and ZnAl2O4 in the ZnO/ZnAl2O4/glass film were 19 nm/0.469 GPa and 11 nm/-0.292 GPa, respectively. The lower Zn/Al molar ratio around 0.035/0.06 produced only ZnO as a single phase, suggesting the Al insufficient quantity. The Si (100) substrate with 0.07 Zn molarity conducted to the Zn2SiO4/ZnO/ZnAl2O4 composite. The Raman integrated intensity bands of ZnO and ZnAl2O4 increases with increasing Zn to Al molar ratio (0.1/0.1 comparatively to 0.07/0.13). The ZnO&ZnAl2O4 crystallinity enhances as Zn molarity increases. The ZnO films in the composites grow with (002) texture. The TC(hkl) value indicated that ZnAl2O4 in the ZnO/ZnAl2O4/glass layer is polycrystalline preferentially oriented along the (311) plane. Spinel ZnAl2O4 oxide onto Si (111) substrate grown according to the (220) orientation. Crystallites are larger in ZnO/ZnAl2O4/Si than in ZnO/ZnAl2O4/glass. The ZnO/ZnAl2O4 film onto glass substrate is transparent in the visible and near infrared regions and sensitive to UV absorption, as characterized by UV-Vis spectroscopy. The ZnO and ZnAl2O4Egvalues in the ZnO/ZnAl2O4/glass composite were 3.25 and 3.88 eV, respectively.


2011 ◽  
Vol 197-198 ◽  
pp. 208-214
Author(s):  
Xiao Shan Tang ◽  
Da Li

Nitrogen-doped titanium oxide (TiO2-xNx) films were prepared by an improved ultrasonic spray pyrolysis device with buty1 titanate as the titanium source and ammonia as the nitrogen source. X-ray diffraction technique, scanning electronic microscope and UV-VIS spectroscopy were applied to study the microstructure, surface morphology and optical properties of the resulting films. The XRD peak intensity of the as-prepared films decreased with the increasing of nitrogen content and increased with the increasing of temperature, which indicates that the N doping introduced defects or strain in the TiO2film. The SEM results indicate that all the samples have a nano-sized uniform surface. The smallest band gap and best hydrophobicity are obtained at the nitrogen concentration of 4 at. % and deposited at 400°C. The blood compatibility of TiO2-xNxthin films was observed through platelet adhesion. The experiments results show that the amount of thrombus on the TiO2-xNxthin films is much less than that of pyrolytic carbon. The experimental results show that the nano-sized TiO2-xNxthin films will be a new kind of promising materials applied to artificial heart valve and endovascula stent.


2018 ◽  
Vol 15 (2) ◽  
pp. 147-156
Author(s):  
Rebeka Rudolf ◽  
Urban Ferčec ◽  
Mohammed Shariq

Background: This review provides a closer look at recent work in the field of fireworks manufacture, which could see the replacement of micron-sized particles with their nano-scaled counterparts. Moreover, we also discuss micron-sized particles as well as nanoparticles (NPs) from K, Fe, Al, Ti, Ba, etc., that are produced in the atmosphere as a result of these fireworks. One of the possible technological substitutes for fireworks is presented in detail, i.e., the use of ultrasonic spray pyrolysis (USP) technology. Method: We searched Google, Web of Science and PubMed for a literature survey of fireworks and their products: firecrackers, micron-sized and nanoparticles. Moreover, we used some of our own knowledge and experimental data to strengthen the possibility of simulating the synthesis of firework products on the laboratory scale. Results: The use of nano reactants and oxidisers has seen a substantial increase in the sound efficiency and a decrease in the amount of chemicals used, making fireworks more eco-friendly. The application of Al- and Ti-based nano flash powder in the size range from 35 nm to 50 μm resulted in a significant improvement in the ignition properties of the fireworks. Under changing aerodynamic conditions, it is difficult to collect them as samples for real-time monitoring, needed for their characterization or the testing of their harmfulness under laboratory conditions. As a result, NPs below 100 nm in the surroundings could be easily inhaled into the lungs and cause more pulmonary and respiratory problems than micron-sized particles. USP produces nanoparticles in the laboratory that could replace the conventional micron-sized firecracker raw materials, or nanoparticles that are similar to those formed by fireworks. It will also help to identify the physiochemical properties of the airborne particulates in order to understand and evaluate their impact. </P><P> This review could be valuable for a controlled economic synthesis through USP, and in the use of nanopowders in pyrotechnology that could reduce pollution to a great extent, thus contributing to the growth and good practise of the fireworks industry. With respect to the USP synthesis, we have also discussed in detail the physical (size, shape) and chemical (composition) characteristics of Al2O3 and TiO2 NPs from different precursors and their temperature ranges. An in-depth explanation for a comparative analysis for the formation mechanism of nanoparticles through both fireworks and USP is presented in the final section. We can produce nanoparticles in the laboratory with ultrasonic spray pyrolysis that have similar properties to those produced from fireworks and can then be used for further testing.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Inti Zumeta-Dubé ◽  
José Manuel García Rangel ◽  
Jorge Roque ◽  
Issis Claudette Romero-Ibarra ◽  
Mario Fidel García Sánchez

AbstractThe strong facet-dependent performance of glass-supported CeO2 thin films in different applications (catalysis, smart windows, etc.) has been the target of diverse fundamental and technological approaches. However, the design of accurate, cost-effective and scalable methods with the potential for large-area coverage that produce highly textured glass-supported CeO2 thin films remains a technological challenge. In the present work, it is demonstrated that under proper tuning conditions, the ultrasonic spray pyrolysis technique enables one to obtain glass-supported polycrystalline CeO2 films with noticeable texture along both the (100) and (111) directions, as well as with randomly oriented crystallites (no texture). The influence of flow rates, solution molarity, and substrate temperature on the texture and morphological characteristics, as well as optical absorption and Raman response of the deposited films, is evaluated. The obtained results are discussed on the basis of the combined dependence of the CeO2-exposed surfaces on the thermodynamic stability of the corresponding facets and the reaction kinetics, which modulate the crystallite growth direction.


2021 ◽  
Vol 44 (2) ◽  
Author(s):  
Ovier Obregon ◽  
José A Luna-Lopez ◽  
Pedro Rosales ◽  
Mario Moreno ◽  
Abdu Orduña-Diaz ◽  
...  

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