Polymers are intrinsically poor thermal conductors, which is ideal for good thermoelectric behavior, but low electrical conductivity (s) and thermopower (S) have excluded them as feasible candidates for thermoelectric applications.  By adding single-walled carbon nanotubes to a polymer emulsion, we demonstrate that polymer nanocomposites can exhibit true thermoelectric behavior (i.e., generate electricity via a thermal gradient).  These 'segregated network' nanocomposites exhibit electrical conductivity as high as 200,000 S/m and maintain a reasonable S (35 � 50 �V/K).  This high electrical conductivity can be obtained while maintaining low thermal conductivity, which is very close to the intrinsic thermal conductivity of the polymer (k ~ 0.2 W/m�K).  Calculated thermoelectric figures of merit (ZT = S2sT/k) are as high as 0.35 for these composites, making them competitive with inorganic semiconductors at room temperature, but work to increase S is ongoing. These composites are lightweight and relatively flexible when compared with traditional semiconductor thermoelectrics (e.g., bismuth telluride).  Additionally, these water-based systems can be applied like a paint, which should further improve their usefulness in harnessing waste heat from a variety of sources (e.g., exhaust manifolds or the human body).

Thermoelectric polymer nanocomposites

244th National Meeting (2012)

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