High-Efficiency Heat Dissipation Coating Implemented with Stepwise Thermally Conductive Pathway using Polymer-Nanocoated Thermal Filler

Recently, electronic devices have been rapidly integrated in accordance with trends toward miniaturization, thinness, high performance, and multifunctionality. Consequently, the thermal management design within these devices has become critical in maintaining stable performance. Effective heat dissipation technologies, particularly, thermally conductive pastes and coating films, are essential for this purpose. Efficient heat transfer and dissipation in these coating pastes depend on the dispersion of thermally conductive particles to form a uniform thermal network, thereby minimizing phonon scattering. Our study introduces a novel approach that applies a Parylene nanocoating method to the surfaces of thermally conductive filler particles, departing from existing studies that relied on dispersants for uniform dispersion. Consequently, when applying Parylene-nanocoated alumina particles as a filler, a similar or better uniform particle dispersibility was achieved than when using dispersion stabilizers. In addition, the thermal conductivity and diffusivity of the thermally conductive film when using Parylene-coated fillers were significantly enhanced, reaching up to 1.49 W m^-1 K^-1 and 6.2 × 10^-7 m² s^-1, respectively, compared to 0.83 W m^-1 K^-1 and 2.9 × 10^-7 m² s^-1 with the conventional method using dispersant, improving approximately 1.79 times. This could be attributed to the improved dispersibility of thermally conductive fillers and the efficiently configured heat pathway within the coated films, arising from the stepwise thermal conduction through the polymer binder (0.2 W m^-1 K^-1), coated Parylene (0.6 W m^-1 K^-1), and alumina (20 W m^-1 K^-1). These findings present a groundbreaking concept in high-performance thermally conductive coatings and are expected to become a core technology for practical industrial applications.