Thermal Conductivity of Self-Assembling Symmetric Block Copolymer Thin Films of Polystyrene-Block-Poly(methyl methacrylate)

The thermal conductivities of both disordered and self-assembled symmetric polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) copolymer films were measured using time-domain thermoreflectance (TDTR). The variation in out-of-plane thermal conductivity with changing block copolymer thickness is similar to that of PMMA polymer brushes and thick spun-cast films. The results suggest that the interfaces between the PS and PMMA, and reorganization of the PS and PMMA chains around these interfaces, do not significantly affect the thermal transport in these PS-b-PMMA films. However, for thin PS-b-PMMA films, the thermal boundary resistances at the sample interfaces limit the thermal transport.