توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Adsorption of Polyethylene glycol with Various Molecular Weight on the Zinc Oxide Nanoparticle
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۴
Adsorption of polyethylene glycol (PEG) with various molecular weight and concentration on the surface of zinc oxide nanoparticle has been investigated. Adsorption of PEG was accomplished on the surface of ZnO particle mainly via –OH group through hydrogen bonding. Using Brookfield rotary viscometer, the thickness of the adsorbed polymer layer on zinc oxide particles was calculated on the basis of suspension viscosity via the extended Einstein equation. Increase in polymer molecular weight and concentration leads to increase in thickness of adsorbed layer on the inorganic particle.<\div>

۲Studying the adsorption of PEG and PVA on the Zinc oxide nanoparticles
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۸
Zinc oxide (ZnO) nanoparticles, a member of Wurtzite family, are one of the most important nanostructures. ZnO has got three advantages Comparing to other oxide. First, it is a semi–conductive substance with a band gap 3.37 eV and the high excitation energy of 60 meV. It also has a emission near the ultraviolet. Second, it is piezoelectric and is frequently used in sensors and reducers. Third, it is biodegradable and non–poisonous. Aggregation is common problem that occurs during the formation of these particles. One of the methods to overcome this problem is to coat the particles by various materials. Polymer coating is an effective way for modifying the particles surface. Polymer adsorption by nanoparticles improves the stability of the suspension against aggregation. In this study, PEG and PVA are used in order to prevent ZnO nanoparticles from aggregation, and also important and effective factors of polymer adsorption such as molecular weight are discussed. The adsorption process is analyzed by IR, the size and the structure of ZnO nanoparticles by XRD, the amount of molar mass of the adsorbed polymer by TGA, and finally, the aggregation and accumulation of the nanoparticles by SEM.<\div>

۳Synthesize and Characterization of Tin Oxide Nanowire Using Vapor–Liquid–Solid Technique
اطلاعات انتشار: سومین کنفرانس نانوساختارها، سال
تعداد صفحات: ۴
SnO2 nanowires have been successfully synthesized on silicon substrates using Vapor–Liquid–Solid (VLS) method. We employed SnO powder as the starting material (located in the hottest point of the furnace), and a thin layer of Au (with the thickness of 5 and 12nm) as the catalyst. The nanowire growth carried out in a horizontal tube furnace at the temperature of 900 C. The morphology and microstructure of nanowires are characterized by means of scanning electron microscopy (SEM) and X–ray diffraction pattern. The SEM images reveal that no nanowire was grown on the substrate without a gold catalyst, while SnO2 nanowires were grown on the substrates that were coated by Au. The diameter of nanowires that have catalyst with thickness of 5nm is about 50–100 nm while those that were grown on 12nm thick catalyst have a diameter between 80–300nm, indicating that the diameter of nanowires depends on the catalyst thickness. The effect of distance between substrate and powder source (SnO) in the furnace is also investigated and the result shows that the nanowires grown on the substrates close to the powder source are island shapes, while those grown on the substrates far from the SnO powder source are in the form of continuous thin film, resulting that the substrate temperature effects the nanowire structure. The X–ray diffraction patterns indicate that the structure of SnO2 nanowire is in the form of tetragonal with lattice constant of a=b=0.443nm and c=0.372nm.<\div>
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