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العنوان
Preparation and Spectroscopic Analyses of Nano Metal Oxides /
المؤلف
Abdalla, Hend Ahmed Mohamed Ezzat.
هيئة الاعداد
باحث / هند أحمد محمد عزت عبد الله
مشرف / نادرة عبد اللطيف ندا
مشرف / مدحت أحمد عبد الخالق إبراهيم
مشرف / اسامة محمد محمود عثمان
مشرف / معروف مروان حجازى
تاريخ النشر
2021.
عدد الصفحات
284 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
الفيزياء والفلك (المتنوعة)
تاريخ الإجازة
1/1/2021
مكان الإجازة
جامعة عين شمس - كلية البنات - الفيزياء
الفهرس
Only 14 pages are availabe for public view

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Abstract

As nanotechnology has grown rapidly in recent years, the research of nanocomposites has become progressively important to produce new materials for sophisticated technologies. Nanocomposites are the best approach to follow the requirements of multifunctional materials, since they are not only the flexible material type, but also have a high degree of integrated interaction. It is also predicted that nanocomposites would have a significant effect on the global economy and industry. The key point is that several of manufacturing fields such as optical and electrical, chemical and transportation industries.
The present research is implemented to using molecular modeling to simulate the interactions among the polymer matrix and MOs that provide the experimental work. The proposed study is designed to the preparation of MO using chemical processes, such as the process of precipitation. MOs are characterized and then functionalized to be used in space applications using a natural polymer matrix that MO may improve its electronic, optical properties and thermal stability.
To simulate the interactions between the polymer matrix and MOs, three theoretical models were considered. Calculations were carried out using DFT at B3LYP level with LANL2DZ basis set.
 The first model simulates and studies NP interactions with MOs such as ZnO and CuO, such as Cel, Cs and NaAlg, to improve NP electronic properties and thermal properties. The first model results indicates that:
• CuO interacted with Cel and Cs was the most efficient MO, while NaAlg reported non-significant changes.
• Therefore, new nanocomposites with high electronic properties and thermal stability were developed by enhancing Cel or Cs with MO to be used in electronic devices and sensing applications, such as humidity sensors.
 GO is therefore a promising electronic material that provides more enhancements to the NP/MO, simulating and studying GO interactions with NP/MO nanocomposite to enhance electronic properties and thermal stability in the second model that:
• Electronic properties showed an increase in GO/Cel/OCu and GO/Cs/OZn improvements.
• Calculations of thermal properties ensured that GO improved physical NP/MO, thermal stability and reactivity.
• Resulting in the current GO/NP/MO structure of materials having significant properties, especially GO/Cel/MO and GO/Cs/MO, while GO/NaAlg/MO did not make significant changes.
• It can be concluded from all the data that, because of the combination of high carrier mobility, active sites and reactivity, the investigated combination of NP/MO/GO offers excellent optoelectronic applications.
 Significantly, it could be found from the assignments of the third model of Cs/ZnO/GO interactions that:
• The studied hybridization of Cs/ZnO/GO in an adsorbing mechanism via the O of the carboxyl group COOH of GO which greatly improves electronic properties and thermal stability.
• Hybridization of Cs/ZnO/GO offers appropriate applications as a corrosion inhibitor due to a combination of high carrier mobility, low surrounding field responsiveness and thermal stability.
For experimental work, Synthesized ZnO with the precipitation method and GO with the Hummers method were studied using various techniques to validate the nanoscale preparation of ZnO and GO.
After that, preparation of Cs and Cs/ZnO composite films were prepared using casting method with different concentrations of ZnO as 10, 20, 30, 40 and 50% and Cs/ZnO/GO hybrid composite with two different methods as casting and one pot method were verified using:
 FTIR and NMR spectroscopy which confirmed that the interaction occurs through NH2 function group of Cs with ZnO and the O of the carboxyl group COOH of GO as recommended in theoretical model.
 Also, SEM Cs/ZnO and Cs/ZnO/GO prepared by one pot hybrid method, there is small white rode shape and other agglomerate on Cs surface which regarded that there are many interactions between Cs, ZnO and GO edges.
Optical properties were studied using UV-Vis. spectroscopy and calculations which revealed that:
 The optical properties increased with increasing the filler ZnO concentration, values of direct and indirect band gap energy are decreased compared to pure Cs and it has a lower value for Cs doped with ZnO and GO and Cs/ ZnO /GO prepared one pot hybrid method is the lowest value of indirect and direct optical band gap.
 Cs doped with both ZnO and GO give higher value of Eu compared to other sample that is mean that it has higher degree disorder and has high conductivity which confirm theoretical model.
Furthermore, for thermal behaviour study all prepared samples of Cs, Cs/ZnO with differing degrees of doping and Cs/ZnO/GO composites with two separate ways were subjected to TGA analysis that the result indicated that:
 Cs/ZnO nanocomposite and Cs/ZnO/GO hybrid composite decomposition temperature were more enhanced in comparison with Cs.
 Cs/ZnO nanocomposite and Cs/ZnO/GO hybrid composite had higher residual mass percentages relative to Cs due to the rise in temperature.
 In addition, certain improvements in the degradation behavior of composites are found relative to the Cs which could be seen to decrease the degradation of Cs with increasing the filler and the highest percentage was one pot nanocomposite for Cs/ZnO/GO.
 Cs/ZnO/ GO one pot nanocomposite exhibits significant enhancement in thermal stability compared to Cs which confirm theoretical model.
Finally, Cs/ZnO/ GO prepared by one pot hybrid composite method that is best method for preparing Cs/ZnO/GO hybrid composite. The shape and size of the nanomaterials has a great influence on the electrical and optical properties. The preparation of Cs / ZnO / GO by one pot hybrid composite method produces a compound with optical, electrical, and thermal stability properties that can be used as optoelectronic and corrosion inhibition material which can be used for space applications.