Gold coating reduces thermal conductivity of oriented polypropylene fibers

Self-heating methods are widely used in thermal conductivity measurements of polymer fibers. In these methods, a thin metallic film needs to be coated on the fibers if the fibers are electrical insulators. In this paper, the thermal conductivities of oriented polypropylene (PP) fiber samples before and after gold coating were measured. The results show that the gold-coating process can reduce the thermal conductivity of oriented PP fibers by about 50%. Therefore, the self-heating methods are not appropriate for thermal conductivity measurements of insulative polymers. This finding is important to the research of thermal conductive polymers.