الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Nanofibers are one form of nanostructures that have received a growing interest as a result of their unique properties and wide potential applications. Electrospinning is one of the methods used in the fabrication of nanofibers. Electrospinning technique is superior compared to other techniques used; due to its simplicity.
This study provides a complete understanding of the electrospinning process and the parameters affecting it through analytical and experimental study of the process. Fabrication of nanofibers from polymer solution is carried out at different operating conditions. A theoretical model (Discrete Bead Model) is implemented to simulate the jet path and study the parameters that affect the electrospinning process and the resulting nanofibers. Bending instability initiation is explained using Earn Shaw theorem.
One of the crucial factors in the electrospinning process that affects the formation of nanofibers, is electric field distribution and uniformity. Uniform electric field distribution produces finer and more homogeneous fibers. Different configurations for the electrospinning setup leads to formation of nanofiber mat with advanced characteristics that can be useful for different applications. Also, many configurations can be useful in terms of rate of productivity, deposition area and operation time.
It is desired to study the effect of electric field uniformity on the produced fibers. FEM (Finite Element Method) is used to analyze the electric field profile for different electrodes including disc, cylinder and cone electrodes; through COMSOL Multiphysics software. A comparison between different electrodes is performed according to their electric field strength and uniformity. The proposed electrodes were manufactured and tested experimentally. Their effect on controllability of the process which is defined as the possibility of fibers deposition at a small spot is examined. The resulting nanofiber mat is analyzed using SEM (Scanning Electron Microscope). IMAGEJ; an image analysis software is used to analyze the resulting images from SEM and determine the diameters distributions of the resulting fibers. The electrodes are compared according to their deposition area, resulting fibers homogeneity, fibers diameter distributions and thickness of the fiber mat.
To the best of my knowledge, the cone hasn’t been previously studied as a potential electrode in the electrospinning process. The disc electrode was used in multi jet electrospinning and the analysis included experimental results and the study of uniformity criteria but didn’t include any modeling attempts. The cylinder electrode was previously used in the electrospinning setup as an auxiliary electrode connected to a spinning nozzle.