Characterization of electrical conductivity of carbon fiber/epoxy composites with conductive AFM and scanning microwave impedance microscopy

This thesis investigates the electrical conductivity of IM7 carbon fibers using two Atomic Force Microscope (AFM) –based techniques: Conductive AFM (C-AFM) and Scanning Microwave Impedance Microscopy (sMIM). Unidirectional IM7/977-3 carbon fiber/epoxy laminates were manufactured and examined with these two techniques. C-AFM was used to measure the bulk resistivity of IM7 fibers at (1.9 ± 1.1) x 10-3 Ω∗cm. Given that the uncertainty of these measurements is rather large, implementation of calibration experiments is needed. sMIM experiments revealed large nano-scale spatial variations in the axial and transverse conductances of IM7 fibers. Attempts were made to quantify sMIM results through construction of experimental and computational calibration curves, but neither of these efforts was successful in yielding conductivity measurements that agreed with the measurements made with C-AFM or the manufacturer specification. Refinements to the computational methodology such as improved material property inputs and better isolation of the sMIM signal could yield promising future results for sMIM characterization of conductivity.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• McKenzie, Andrew B.

Contributors dc:contributor

• White, Scott

• Carbon fibers
• Composites
• Electrical conductivity
• Atomic Force Microscopy
• Conductive Atomic Force Microscopy (AFM)
• Scanning Microwave Impedance Microscopy

Statement dc:rights

• Copyright 2015 Andrew McKenzie

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/88098

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/88098