Conjugated polymers possess a unique combination of electrical and optical properties similar to those of metal and inorganic semiconductors, but also exhibit the attractive properties associated with conventional polymers. The utility of these polymers as thermal interface material in semiconductor devices, photoactive materials in light emitting diodes and solar cell and as substrates for sensing depends largely on (i) the directional carrier mobility through the polymer, (ii) the amount of surface area available to form interface with other photoactive, biological or chemical species (iii) the contact area and resistance between polymer and surfaces (metal electrode). Further, the alignment of polymer chains with enhanced molecular and supermolecular order at the nanoscale can reduce defects and improve the mechanical strength and thermal/electrical conductivity in the direction of alignment significantly. Herein, we report the template-assisted fabrication of conjugated polymer (polythiophene) nanostructures on metal foils and their application as thermal interface materials (TIMs). The polythiophene (Pth) nanostructures of varying diameters and length were grown potentiostatically using a three-electrode electrochemical cell.  The current-time profiles for Pth growth in nanopores, indicate that, the formation of polymer nanostructures occurs by instantaneous nucleation and subsequent two-dimensional growth. The length and morphology of nanostructures were controlled by the monomer concentration, applied potential and the total charge passed through the electrochemical cell. A photoacoustic (PA) technique was used to measure the thermal resistances of Pth nanotube arrays dry-adhered to different substrates to form the interfaces. The total thermal resistance of a typical (~ 200 nm diameter) Pth nanotube interfaces are comparable to soldered joints.

Electrochemical synthesis of vertically aligned polythiophene nanostructures on metal foils for thermal interface applications

243rd National Meeting (2012)

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