Process variables controlling consistency of carbon nanotube forest growth
Name
890130256-MIT.pdf
Description
Full printable version
Size
3.68 MB
Format
Adobe PDF
Checksum (MD5)
33ccc8882e0992a6e2a826c32ff29215
Author(s)
Vincent, Hanna Megumi
Advisor(s)
Brian L. Wardle and Carl V. Thompson.
Date Issued
2014
Publisher
Massachusetts Institute of Technology
Abstract
Aligned arrays of carbon nanotubes (A-CNTs), called CNT forests, are the precursor for controlled-morphology macroscopic nanocomposites and nanoengineered composites due to theirscale-dependent, tunable physicall properties. Applications include polymer and ceramic matrix nanocomposites (PNCs and CMNCs), nanostiching as laminate interply reinforcement, as well as in supercapacitors, MEMS devices and electrodes for ion actuators and sensors. A key component of manufacturing materials comprised of A-CNTs is controlling the morphology and geometry of the CNT forest. Current laboratory findings show significant variability in CNT forest growth characteristics, and an experimental study was conducted to better understand and control for the observd process variations. An exploratory investigation of growth parameters allowed for a local optimization of growth temperature and hydrocarbon flow rates, as well as an acceptable range of sample placement in the CVD furnace to achieve ~1mm tall CNT forests. Results from this investigation led to the conclusion that the significant inconsistencies between consecutive growths must be due to factors out of direct control, mainly humidity. A new system is being developed to better control for and monitor water in the furnace. A second investigation focused on post growth cool down effects, and the possible shortening (deforestation) of CNTs at high temperatures without a renewing source of the carbon precursor. Deforestation conditions did not lead to CNT shortening.
Description
Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 337-39).
Subjects
Materials Science and Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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