Tailoring Carbon Nanotube Density for Modulating Electro-to-HeatConversion in Phase Change Composites.

We report a carbon nanotube array-encapsulatedphase change compositein which the nanotube distribution (or areal density) could be tailoredby uniaxial compression. The n-eicosane (C20) wasinfiltrated into the porous array to make a highly conductive nanocompositewhile maintaining the nanotube dispersion and connection among thematrix with controlled nanotube areal density determined by the compressivestrains along the lateral direction. The resulting electrically conductivecomposites can store heat at driven voltages as low as 1 V at fastspeed with high electro-to-heat conversion efficiencies. Increasingthe nanotube density is shown to significantly improve the polymercrystallinity and reduce the voltage for inducing the phase changeprocess. Our results indicate that well-organized nanostructures suchas the nanotube array are promising candidates to build high-performancephase change composites with simplified manufacturing process andmodulated structure and properties. [ABSTRACT FROM AUTHOR]