Document Type

Honors Thesis

Publication Date

Spring 2015

Abstract

The synthesis, characterization and application of carbon nanotubes (CNTs) have received substantial attention in recent years, particularly in the field of polymer nanomaterial composites (PNCs). CNTs possess impressive thermal, electrical and mechanical properties, and PNCs incorporating them have shown multitude increases in these same properties with relatively low percolation thresholds [1]. Electrospinning is an effective and tunable materials synthesis platform for the manufacture of micro and nanofibers that has shown particular promise in the fields of carbon nanotube PNC processing due to the favorable isotropic alignment CNTs undergo due to the electrospinning process [2]. CNT alignment has been shown to increase the thermal, electrical and mechanical properties of carbon nanotube PNCs significantly compared to unaligned anisotropic materials [3]. Electrospinning is being explored as a manufacturing platform for micro and nanoelectromechanical systems, sensors, biomedical materials, filtration and catalysis. Carbon Nanotube PNCs are being widely explored for applications in these areas as well [4], [5]. The most pressing processing challenges for CNT doped PNCs is prevention of CNT bundling and agglomeration. This work explores the synthesis via electrospinning of well dispersed CNT doped PNC nanofibers with enhanced electrical properties using poly (vinyl alcohol) (PVA). Previous work has accomplished increased conductivity of PVA thin films and anisotropic electrospun fiber mats, but none have explored the conductivity of individual and aligned electrospun micro and nano fibers of PVA with CNTs [6]. The electrical and optical properties of these aligned individual and bundled nanowire assemblies are being investigated. Polymer doping was performed with both pristine and chemically modified carbon nanotubes. A comparison of the pristine and chemically modified nanotubes and their effects on the conductivity and dispersability is underway, as well as variations on the chemical modification parameters. A four-point source meter unit protocol for conductivity measurements is being developed and utilized for the measurement of PNC products. At the time of writing this report, conductivity was not achieved in any CNT doped PVA products. These conductive fibers are being explored and developed as a sensor, actuator, and optoelectronic device technology platform. Through surface modification, doping and other semiconductor fabrication techniques with various metals, polymers and nanomaterials, specific phenomena will be targeted and utilized for device function.

Comments

Research Advisors:

Dr. Jack Skinner Montana Tech Department of General Engineering

Dr. Katie Hailer Montana Tech Department of Chemistry

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