Development and implementation of nanoscale materials in engineering applications

Collins, Michael

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https://hdl.handle.net/2142/49356 Copy

Description

Title

Development and implementation of nanoscale materials in engineering applications

Author(s)

Collins, Michael

Issue Date

2014-05-30T16:39:49Z

Director of Research (if dissertation) or Advisor (if thesis)

• Jones, Barclay G.
• Marsh, Charles P.

Department of Study

Nuclear, Plasma, & Rad Engr

Discipline

Nuclear, Plasma, Radiolgc Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Nanoparticles
• Quantum Dot
• Cadmium Selenide/ Zinc Sulfide
• Pressure
• Carbon buckminsterfullerene
• Wettability
• Hydrophobicity
• Organosilane
• Nanostructure

Abstract

Nanoparticles used in two unique ways are examined for the purposes of utilizing their unique characteristics for specific applications. The first of the nanoparticles examined, Cadmium Selenide/ Zinc Sulfide core/shell Quantum Dots with an expected emission peak of 640nm, were studied for the purpose of creating a non-invasive stress gauge. The Quantum Dots observed had Gaussian fitted emission peak shifts when exposed to a 5mW 405nm laser and pressures ranging from 0-100MPa. The emission peak shifts experienced appeared near linear over the ranges of 5-100MPa with an average wavelength shift of -1.5nm per 100MPa. The Quantum Dot emission peak to control emission intensity ratio shifted over this range of pressures but the methods of measuring the intensity are highly variant and require more refinement prior to application. Though the induced emission peak shift is large enough to be detectable at high pressures (>100MPa), the error of the emission peak calculation is +/-0.045nm and there is an issue of gradual emission peak shift over time. Further study of Quantum Dot as a stress gauge requires higher control of the declining emissions with respect to time but gives rise to the notion of using Quantum Dots as an environmental exposure or erosion detector for coatings. The second of the nanoparticles tested was the carbon buckminsterfullerene (C60) in an attempt to create a hydrophobic nanostructured surface. The experiment designed is a procedure by which C60 is attached to a SiO2 surface via the organosilane, N1-[3-(trimethoxysilyl)-propyl]diethylenetriamine. The surface made was exposed to contact angle measurement and X-ray photoelectron spectroscopy (XPS) to determine the status of the functionalization. Contact angle measurement confirmed the existence of a change in the surface chemistry but no hydrophobic surfaces were created as all surfaces had contact angles in the range of 36-67°. The functionalization was further characterized by XPS and it was found that the C60 molecules were hydroxyl and carboxyl functionalized using the plasma process developed. XPS also showed a tangible change in the relationship between carbon and nitrogen after the SiO2 is functionalized with the organosilane and then later with the C60. The change in the C60 attached surface is not enough to state that functionalization had occurred and additional improvements to the procedure are suggested to allow for confirmation. Of the suggestions to improve the procedure, two in particular are of importance. The first of which is that the C60 are still functionalized with hydroxyls reducing the hydrophobicity of the surface and a possible defunctionalization procedure is identified which does not affect the amide bonds but reduces the hydroxyls. The second is the possibility of using larger particles to make detection easier in XPS or other forms of microscopy, as well as improving the amount of bonds and the functionality of the surface.

Graduation Semester

2014-05

Permalink

http://hdl.handle.net/2142/49356

Copyright and License Information

Copyright 2014 Michael Collins

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