Excess thermopower and the theory of thermopower waves.

Self-propagating exothermic chemical reactions can generate electrical pulses when guided along a conductive conduit such as a carbon nanotube. However, these thermopower waves are not described by an existing theory to explain the origin of power generation or why its magnitude exceeds the predictions of the Seebeck effect. In this work, we present a quantitative theory that describes the electrical dynamics of thermopower waves, showing that they produce an excess thermopower additive to the Seebeck prediction.

ZnO based thermopower wave sources.

Exothermic chemical reactions of nitrocellulose are coupled onto thermoelectric zinc oxide (ZnO) layers to generate self-propagating thermopower waves resulting in highly oscillatory voltage output of the order of 500 mV. The peak specific power obtained from ZnO based sources is approximately 0.5 kW kg(-1).

Wavefront velocity oscillations of carbon-nanotube-guided thermopower waves: nanoscale alternating current sources.

The nonlinear coupling between exothermic chemical reactions and a nanowire or nanotube with large axial heat conduction results in a self-propagating thermal wave guided along the nanoconduit. The resulting reaction wave induces a concomitant thermopower wave of high power density (>7 kW/kg), resulting in an electrical current along the same direction. We develop the theory of such waves and analyze them experimentally, showing that for certain values of the chemical reaction kinetics and thermal parameters, oscillating wavefront velocities are possible.

Chemically driven carbon-nanotube-guided thermopower waves.

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(4) times the bulk value, propagating faster than 2 m s(-1), with an effective thermal conductivity of 1.28+/-0.

Modelling the increase in anisotropic reaction rates in metal nanoparticle oxidation using carbon nanotubes as thermal conduits.

Nanostructured energetic materials are attracting attention for their faster reaction rates compared to materials with micron-scale particles. We numerically solve the coupled energy balances for a carbon nanotube with an annular coating of reactive metal, such that coupling to thermal transport in the nanotube accelerates reaction in the annulus. For the case of Zr metal, the nanotube increases the velocity of the reaction front in the direction of the nanotube length from 530 to 5100 mm s(-1).