Excellent Anti-fouling Properties and High Thermal Conductivity of Superhydrophobic SiC/PU-Coated BNNS Composite Films

Owing to their excellent thermal conductivity (TC), boron nitride nanosheet (BNNS)-filled polymer composite films have aroused great interest in their use for heat dissipation in the electronics industry. However, the application of BNNS composite films is limited by their lack of hydrophobicity and non-fouling properties, as well as their low corrosion resistance, affecting their long-term stability in specific environments, such as high humidity environment, rainwater erosion, corrosion from pollutants, and dust pollution. In this work, a composite film with both superhydrophobicity and a high TC was constructed by spraying a silicon carbide (SiC) and polyurethane (PU) coating modified by perfluorooctylmethoxysilane (PFTMS) onto the surface of BNNS-filled polymer composite films. The PFTMS coupling agent not only improved the dispersibility of SiC in PU and the combination of SiC with PU, but also reduced the surface free energy of the film. The optimal mass ratio of SiC to PU for the SiC/PU composite coating was 1.2:1, resulting in superhydrophobic properties with a contact angle (CA) of 168.6 ± 1.3° and a rolling angle (RA) of 2.8 ± 1.2°. Meanwhile, SiC with higher TC also allowed the BNNS-filled composite films to maintain a high TC (32.3 W/m K). The composite films exhibited excellent TC and self-cleaning ability, as well as improved mechanical and chemical stability of the surface, which provides a strategy for enhancing the environmental adaptability of BNNS composite films and broadening their application scenarios. Graphical Abstract Superhydrophobic SiC/PU-coated BNNS composite films with excellent anti-fouling properties and high thermal conductivity