Thermal and Electrical Transport Measurements of Single-Walled Carbon Nanotube Strands
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Thermal and Electrical Transport Measurements of Single-Walled Carbon Nanotube Strands Diana-Andra Borca-Tasciuc1, Yann LeBon2, Claire Nanot2, Gang Chen3, 1, Theodorian BorcaTasciuc4,*, Anyuan Cao5, Robert Vajtai5 and Pulikel M. Ajayan5 1
Mechanical and Aerospace Engineering Department, University of California at Los Angeles Los Angeles, CA 90095, U.S.A. 2 ENSMA, Futuroscope, France 3 Mechanical Engineering Department, Massachusetts Institute of Technology Cambridge, MA 02139, U.S.A. 4 Mechanical and Aerospace Engineering Department, Rensselaer Polytechnic Institute Troy, NY 12180, U.S.A. 5 Department of Materials Science and Engineering, Rensselaer Polytechnic Institute Troy, NY 12180, U.S.A.
ABSTRACT
This work reports temperature dependent thermal and electrical properties characterization of long (mm size) single-walled carbon nanotube strands. Electrical properties are measured using a 4-probe method. Thermal conductivity and specific heat capacity are determined using an AC driven, self-heating method. Normalized values of resistivity, thermal conductivity, specific heat, thermal diffusivity, and the temperature coefficient of resistance are reported. The trends observed in the temperature dependent properties are comparable with previously published data on multi-walled carbon nanotube strands measured with a similar technique.
INTRODUCTION
Thermal and electrical properties of carbon nanotubes (CNT) are of high interest for a variety of applications ranging from nanoelectronics and nanoelectromechanical systems to nanocomposites for thermal management. Previous investigations include theoretical predictions [1], and more recently, experimental studies on the electric and thermal transport properties of carbon nanotube materials including, multiwalled CNT strands and arrays, individual multiwalled tubes, and single walled carbon nanotube mats. [2,3,4,5]. This work reports temperature dependent thermal and electrical properties characterization of a SWCNT strand of ~2 mm length, in the 80-300K temperature range. Electrical conductivity is measured using a 4-probe method. Normalized resistivity is found to increase as ambient temperature is decreased. Temperature coefficient of resistance approaches a constant value as temperature is raised. Thermal conductivity, thermal diffusivity, and specific heat are determined using an AC driven, self-heating method [6]. Normalized thermal conductivity and specific heat *
Corresponding author. Electronic address: [email protected].
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increase linearly with temperature. The results have comparable trends with previously published data on MWCNT [2] characterized with a similar technique. SAMPLE
SWCNT samples have been synthesized with an arc discharge method [7]. Catalyst powders (mixture of Nickel, Yttrium and graphite of 0.7/0.25/0.17g) were put inside a 3 mm dia. 4” deep hole drilled into a 6 mm diameter graphite rod cathode. The arc discharge was performed for about 15 min. under a constant current of 100 A at 400 torr He atmosphere. The SWCNT bundl
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