Date of Award

2017

Degree Type

Thesis

Degree Name

Master of Science in Chemical Engineering

Department

Chemical and Biomedical Engineering

First Advisor

Wirth, Christopher

Subject Headings

Chemical Engineering

Abstract

Single and multi-walled carbon nanotubes (SWCNT & MWCNT) have been studied over the past three decades because of their excellent properties, including their mechanical strength and large electrical and thermal conductivities. Incorporating CNTs into phases necessary for use in consumer or industrial products has been challenging because of strong attractive interactions, heterogeneity, and lack of separation techniques for these nanomaterials. Moreover, there are further challenges incorporating CNTs into multiphase materials because of the many remaining open questions regarding the properties of an interface with CNTs adsorbed or nearby. In the present work, the mechanics and microstructure of a water/air interface laden with industrial grade MWCNTs was studied. Specifically, the properties of an interface laden with MWCNTs that were systematically modified via oxidation in nitric acid were measured. The duration of oxidation was varied, and the surface pressure of the nanotube laden interfaces was measured via a Langmuir-Blodgett trough and microbalance. The elasticity and film relaxation times for MWCNTs with varying extents of oxidation were measured and compared. Data suggests that film elasticity increased with increased surface oxidation. However, these measurements also revealed that elasticity increased with compression number, suggesting that surface oxidation may have had only an indirect effect on elasticity. Additionally, MWCNT films were observed with an optical microscope and SEM. Micrographs showed evidence of buckling in the films at low modification times. These data together suggest that the films densify at higher modification times, pulling together due to capillary interactions brought on by stronger adsorption to the interface.

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