Browsing by Author "Saravanan, L."

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Dielectric property determination of hybrid Al2O3-filled MWCNT buckypaper by the rectangular cavity perturbation technique
(2015-04-01)
Miao, Hsin-Yuan
;
Liu, Jih-Hsin
;
Saravanan, L.
;
Tsao, Che-Wei
;
Pan, Jui-Wen
This study investigated the complex dielectric permittivity of freestanding multiwalled carbon nanotube buckypaper (MWCNT-BP) and a synthesized hybrid alumina-filled buckypaper (Al2O3-BP) composite with different alumina loadings (5-30 wt%). The non-destructive microwave transmission technique for complex permittivity determination involving cavity perturbation was employed to characterize a set of Al2O3-BP sheets. This was done by filling a rectangular cavity resonator with a standard dielectric Teflon sample and then performing permittivity measurements for the buckypaper (BP) samples in the X-band frequency range (7-12 GHz). Field-emission scanning electron microscopy (FESEM) was used to analyze the morphology of the MWCNT-BP and the alumina-loaded BP composites. DC electrical resistivity measurements clearly demonstrated conductor-insulator transition. The effect of alumina loadings on the dielectric properties of the synthesized hybrid Al2O3-BP sheet is discussed.
Microwave Absorption Properties of Silver Doped MWCNT Buckypaper
(2013)
Tsao, Che-Wei
;
Saravanan, L.
;
Liu, Jih-Hsin
;
Miao, Hsin-Yuan
;
Wang, Li-Chih
Microwave absorbing property of composites containing Ag nanoparticles filled multiwalled carbon nanotube buckypaper (Ag-BP) has been investigated. Buckypaper doped with silver was prepared by direct dispersion and filtration method. From the low temperature resistivity measurement it was found that increasing doping level decreases the electrical conductivity of the buckypaper. 30 wt. % and 40 wt. % of Ag-BP samples shows the maximum transmission coefficient, with very high conductivity. The results demonstrate that microwave absorption of Ag-BP was attributed only due to the dielectric loss rather than other losses. The absorption peak frequency of the Ag/MWCNTs-BP can be controlled easily in the presence of Ag nanoparticles into the CNT mats.