Low Thermal Conductivity and High Electrical Conductivity in PEDOT:PSS/DMSO Composite with Hollow Glass Microspheres

Advanced polymer materials that concurrently deliver high electrical and low thermal conductivity are vital for next-generation electronic and thermal-insulation technologies. While conventional strategies usually incorporate electrically conducting fillers into thermally insulating polymers, they often lead to an undesired increase in thermal conductivity due to enhanced lattice or electron transport. In this study, a PEDOT/PSS-based polymer composite system incorporating dimethyl sulfoxide (DMSO) and hollow glass microspheres (HGMs) is developed, and the thermal, electrical, and thermomechanical properties are examined. Thermal properties of the polymer film material were accurately measured using pump probe spectroscopy to determine the interfacial thermal transport between PEDOT:PSS and glass. By adding 2 vol % DMSO and 27 vol % HGM to PEDOT:PSS, a high electrical conductivity of 270 S cm–1 and a low thermal conductivity of 0.62 W m–1 K–1 were obtained. Our pump–probe measurements revealed that the interfacial thermal conductance (ITC) between the polymer matrix and the HGM is independent of the electrical properties of PEDOT:PSS. The experimental results showed excellent agreement with the theoretical modeling for both electrical and thermal conductivities. Furthermore, digital image correlation was employed to assess the temperature-dependent dimensional stability of the polymer composites under ambient conditions. This polymer-based composite, which is easy to process and has a unique combination of high electrical conductivity and low thermal conductivity, has considerable promise for use in electronic devices, sensors, and thermal insulation applications.