Chemically Driven, Carbon Nanotube-Guided Thermopower Waves

Coupling an exothermic chemical reaction with a nanotube or nanowire possessing high axial

thermal conductivity creates a self propagating reactive wave along its length. Such waves are

realized using a 7 nm cyclotrimethylene-trinitramine (TNA) annular shell around a multi-walled

carbon nanotube and are amplified by more than 100 times the bulk TNA value, propagating more

than 3 m/s, with an effective thermal conductivity of 1.00 ± 0.35 kW/m/K at 2860 K. This wave

produces a concomitant electrical pulse of disproportionately high specific power, as large as 7

kW/kg, that we identify as a thermopower wave. The specific power of such thermopower waves

demonstrates an unusual inverse scaling with system size, highlighting their utility as sub-micron

and nano-sized pulse power sources. The reaction also produces an anisotropic pressure wave of

exceedingly high total impulse per mass of 300 N-s/kg and specific impulse per total mass (5.5

s/µg) having applications to micro-propulsion and actuators.