| Summary: | 碩士 === 東海大學 === 電機工程學系 === 101 === Since 1991, Carbon nanotubes (CNTs) have been caused a worldwide wave of research interests because of its unique characteristics about optical, electrical and magnetic, but dielectric property of CNTs have rarely been reported because of so tiny to be measured by traditional method.
In this study, we use multi-walled carbon nanotubes (MWCNTs) and make CNTs to suspension, and then filtrate the suspension to form a bulk macroscopic material called Buckypaper (BP). The experiment has two parts, one is doping different weight percentages of alumina powders by dispersing Al2O3 into the CNT suspension, and the other is coating different metal-oxide (Al, Ba, Cu and Mg) on the surface of buckypaper to modify the property of buckypaper. The structural and morphological analysis was carried out by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). From the observed XRD results, we detect the presence of -phase of alumina particles dispersed in the networks of MWCNTs. It is also confirmed through SEM images for different weight percentages.
For discussing the dielectric property variation of buckypaper, we use the standard test fixture and non-contacting method to measure the dielectric constant in the frequency range from 10 KHz to 10 MHz. The results show that the value of dielectric constant of undoped buckypaper is 4. 20% alumina doped buckypaper is 12, found three times of pure buckypaper. After coating 0.01M magnesium oxide, it becomes 19, 4 times of undoped buckypaper. From the result, no matter with low concentration of mixed alumina or coating metal-oxide could create high permittivity of buckypaper.
|
|---|
