Chemically driven carbon-nanotube-guided thermopower waves

Abstract

Theoretical calculations predict that by coupling an exothermic chemical reaction with a nanotube or nanowire possessing a high axial thermal conductivity, a self-propagating reactive wave can be driven along its length. Herein, such waves are realized using a 7-nm cyclotrimethylene trinitramine annular shell around a multiwalled carbon nanotube and are amplified by more than 10[superscript 4] times the bulk value, propagating faster than 2 m s[superscript −1], with an effective thermal conductivity of 1.28±0.2 kW m[superscript −1] K[superscript −1] at 2,860 K. This wave produces a concomitant electrical pulse of disproportionately high specific power, as large as 7 kW kg[superscript −1], which we identify as a thermopower wave. Thermally excited carriers flow in the direction of the propagating reaction with a specific power that scales inversely with system size. The reaction also evolves an anisotropic pressure wave of high total impulse per mass (300 N s kg[superscript −1]). Such waves of high power density may find uses as unique energy sources.United States. Air Force Office of Scientific ResearchNational Science Foundation (U.S.) (Career Award)National Science Foundation (U.S.)ILJU Academy and Culture FoundationKorea (South). Ministry of Education & Human Resources Development (MOEHRD) (KRF-2006-214-D00117