The Low Temperature Resistance Test of Buckypaper and Its Microwave Application

Since 1991, carbon nanotubes (CNTs) have been caused a worldwide wave of research interests because of its excellent characteristics of physical and chemical. In this study, with the idea of bottom up, we filtrated the suspension of CNTs and make it as a sheet-like bulk material, so called random buckypaper (RBP); that makes plenty of CNTs as an isotropic bulk material, and this allows the applications of CNTs in macro-scale achieve. Besides, in order to vary the property of RBP, we added a vortex power to disturb the suspension when filtration, that makes the direction of tube body align along the circumference, and it becomes as an alignment BP (ABP).According to testing, RBP possesses the features of lightweight, sheet-like, robust, high specific surface area, and 78% porosity. Under four probes resistivity test, it shows that the resistivity of ABP along the vortex direction (horizontally) is decreased when vortex speed increased. The results were opposite when the direction is perpendicular. And, after low temperature resistance test, RBP and ABP both show the negative temperature effect phenomenon. It was assumed that BP is a semimetal material with great conductivity ability. Thus, it was considered to be an excellent material for microwave application (multi-band absorption). It would be possible for BP to make a same revolution in material history as semiconductor did (to replace ferroalloy), because of its precedence electrical properties.