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McMaster University

1. Abdalla, Ahmed Mohamed Sayed Ahmed. SYNTHESIS AND CHARACTERIZATION OF MAGNETIC CARBON NANOTUBES.

Degree: PhD, 2017, McMaster University

The superior properties of carbon nanotubes (CNTs) are best manifest in bulk materials when the CNTs are organized in tandem and embedded in a continuous matrix. Decorating the CNTs with magnetic nanoparticles (MNPs) facilitates their expedient organization with a magnetic field. One of the most convenient methods for their decoration is to first treat the CNTs with oxidative acids, and then coprecipitated MNPs in situ. This method results magnetized CNTs that are covalently functionalized with the MNPs. The associated destruction in the CNTs required running a comparative study of this protocol to identify the influence of the acid treatment on the decoration of multiwalled CNTs (MWNTs). Further, we explore means to tune the physical properties of these magnetized CNTs (mMWNTs) by varying the (1) MNP material composition, and (2) MNP:MWNT (w/w) magnetization weight ratio (γ). The resulted composite materials (mMWNTs) are utilized to synthesize a novel and hitherto unreported class of colloidal suspensions (MCCs) for which the dispersed phase, which consists of MWNTs decorated with MNPs, is both magnetoresponsive and electrically conductive. Synthesis of the dispersed phase merges processes for producing ferrofluids and mMWNTs. Later, these MCCs are adapted and engineered to produce a biological ink containing MWNTs that are twice functionalized, first with MNPs and thereafter with the anti-c-Myc monoclonal antibodies (Abs). The ink is pipetted and dynamically self-organized by an external magnetic field into a dense electrically conducting sensor strip that measures the decrease in current when a sample containing c-Myc antigens (Ags) is deposited on it. On the other side, a nondestructive methods to magnetize MWNTs and provide a means to remotely manipulate them is through the electroless deposition of magnetic nickel nanoparticles on their surfaces. The noncovalent bonds between Ni nanoparticles and MWNTs produce a Ni-MWNT hybrid material (NiCH) that is electrically conductive and has an enhanced magnetic susceptibility and elastic modulus. Raising γ (Ni:MWNT weight ratios) increases the coating layer thickness, which influences the NiCH magnetic properties and tunes its elastic modulus. The NiCH was used to fabricate Ni-MWNT macrostructures and tune their morphologies by changing the direction of an applied magnetic field. Leveraging the hydrophilic Ni-MWNT outer surface, a water-based conductive ink was created and used to print a conductive path that had an electrical resistivity of 5.9 Ωm, illustrating the potential of this material for printing electronic circuits. Further, the NiCHs are introduced into an epoxy matrix at low 0.25-1% volume fractions and aligned along the direction of an applied magnetic field, which produces anisotropic bulk properties. However, nanoparticles aligned in perpendicular directions in sequential layers result in an effectively isotropic composite material. Furthermore, the subsequent annealing of the NiCH in the presence of air oxidizes nickel to nickel oxide whereas carbon is… Advisors/Committee Members: Puri, Ishwar K., Engineering Physics.

Subjects/Keywords: Carbon nanotubes; Functionalization; Nanofluid; Magnetic nanoparticles; Electroless deposition; Co-precipitation; Bioinks; Biosensors; Nickel oxide nanotubes; Supercapacitor

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APA (6th Edition):

Abdalla, A. M. S. A. (2017). SYNTHESIS AND CHARACTERIZATION OF MAGNETIC CARBON NANOTUBES. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/21958

Chicago Manual of Style (16th Edition):

Abdalla, Ahmed Mohamed Sayed Ahmed. “SYNTHESIS AND CHARACTERIZATION OF MAGNETIC CARBON NANOTUBES.” 2017. Doctoral Dissertation, McMaster University. Accessed October 23, 2017. http://hdl.handle.net/11375/21958.

MLA Handbook (7th Edition):

Abdalla, Ahmed Mohamed Sayed Ahmed. “SYNTHESIS AND CHARACTERIZATION OF MAGNETIC CARBON NANOTUBES.” 2017. Web. 23 Oct 2017.

Vancouver:

Abdalla AMSA. SYNTHESIS AND CHARACTERIZATION OF MAGNETIC CARBON NANOTUBES. [Internet] [Doctoral dissertation]. McMaster University; 2017. [cited 2017 Oct 23]. Available from: http://hdl.handle.net/11375/21958.

Council of Science Editors:

Abdalla AMSA. SYNTHESIS AND CHARACTERIZATION OF MAGNETIC CARBON NANOTUBES. [Doctoral Dissertation]. McMaster University; 2017. Available from: http://hdl.handle.net/11375/21958

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