Thermal conductivity is an important property for polymers, as it often affects product reliability (for example, electronics packaging), functionality (for example, thermal interface materials) and/or manufacturing cost. However, polymer thermal conductivities primarily fall within a relatively narrow range (0.1-0.5 W m(-1) K(-1)) and are largely unexplored. Here, we show that a blend of two polymers with high miscibility and appropriately chosen linker structure can yield a dense and homogeneously distributed thermal network. A sharp increase in cross-plane thermal conductivity is observed under these conditions, reaching over 1.5 W m(-1) K(-1) in typical spin-cast polymer blend films of nanoscale thickness, which is approximately an order of magnitude larger than that of other amorphous polymers.

High thermal conductivity in amorphous polymer films via ionization-induced chain extension and stiffening, and dense packing.

PEG-treated poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) exhibited an enhanced power factor with increased strain.

Thermoelectric properties of poly(3,4-ethylenedioxythiophene) doped by different amounts of poly(styrene sulfonate) (PSS) were tested under various humidity conditions. The thermoelectric power factor was found to increase with humidity, with a larger increase observed for samples with less PSS content. For these samples with low PSS content, the Seebeck coefficient and electrical conductivity were observed to simultaneously increase as humidity was increased. Thermal conductivity was observed to increase with increasing humidity for samples with low PSS content and decrease for samples with high PSS content. Measurements on thick films soaked by various polar solvents likewise showed an enhancement in power factor.