Block copolymer-templated iron oxide nanoparticles for bimodal growth of multi-walled carbon nanotubes

Since their discovery carbon nanotubes (CNTs) have sparked great interest due to their exceptional mechanical, electrical, and thermal properties. These properties make carbon nanotubes desirable for numerous applications including: nanoelectronics, high-strength composites, energy storage, superhydrophobic surfaces, sensors, and biomaterial interfaces. Bulk synthesis of carbon nanotubes with controlled physical features, i.e. length, diameter, multiwalled vs. single walled, carbon nanotube chirality, etc. is necessary to make full use of carbon nanotubes exceptional properties in commercial aspects. Typical carbon nanotube synthesis processes use chemical vapor deposition (CVD), arc-discharge, and laser ablation. Synthesizing carbon nanotubes via CVD typically involves depositing a thin metal film on a silicon substrate, and heating the substrate so that the thin metal film dewets and forms metallic nanoparticles. A hydrocarbon gas is then flowed over the nanoparticles to initiate carbon nanotube growth. Though these thin metal film catalysts are easy to prepare, they offer poor control over nanoparticle diameters and areal density. It has been shown that physical properties of carbon nanotubes, such as diameter and uniformity of growth, are directly related to the diameter of the catalyst nanoparticle, and that chirality of the carbon nanotube is inversely related to the catalyst nanoparticle diameter. Therefore, fully exploiting the unique properties of carbon nanotubes requires an understanding of how to control catalyst nanoparticle diameters, and thereby carbon nanotube physical characteristics. Bennett et al demonstrated that controllability of nanoparticle diameters is possible using a simple poly(styrene-b-acrylic acid) (PS-b-PAA) amphiphilic block copolymer. The amphiphilic PS-b-PAA block copolymer forms micelles, when dissolved in toluene, with anionic carboxylic acid groups available from the PAA.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Yazzie, Kyle E

Advisor dc:contributor.advisor

• Robert E. Cohen.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/43205

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/43205