Effective surface passive heat dissipation and durable superhydrophobicity are highly desired for promoting more flexible applications of power-intensive energy systems of aluminum and aluminum-based composites. Herein, we developed a simple and universal approach to fabricate durable superhydrophobic composite coatings composed of hexamethyldisilazane-modified silicon carbide nanowires (HMDS-SiCNWs) and fluorosilicone (FSi) resin. The as-prepared superhydrophobic coating on aluminum substrates exhibited excellent water-repellent property, stain repellency, corrosion resistance, and outstanding mechanical durability, largely due to the hierarchical micro-/nanoscale structure and low surface energy created by HMDS-SiCNWs on the FSi resin matrix. The coatings maintained superhydrophobic after exposure to harsh conditions such as knife scraping, tape peeling, and immersing in boiled water and liquid nitrogen for 1 h. When functioned on an Al radiator for a constant 18 W heat source, such a coating can decrease the temperature by as much as 10 °C and improve the cooling efficiency by up to 10%. Therefore, the combined passive heat dissipation and superhydrophobic multifunctional coating shows promising application in heat exchange systems which are required to be exposed to harsh external environments.

The development of low loading fraction nanoscale reinforcements that can be used to improve the dielectric and thermal properties of a polymer remains a challenge by the reason of the insurmountable difficulties with exfoliation and dispersion of polymer nanocomposites. Here, we combined noodle‐like boron nitride nanoribbons (BNNRs) with epoxy resin (EP) by a facile in situ synthesis. The hydroxyl and amino on the BNNRs surface can not only improve dispersibility but also conduct the formation of EP with BNNRs by the in situ ring‐opening reaction. The thermal behavior, dielectric properties, and thermal conductivity of BNNRs/EP nanocomposites with different BNNRs contents were investigated. At an extremely low BNNRs loading fraction of 1 wt%, the thermal conductivity of the nanocomposite increased 48%, which is attributed to the long continuous heat conduction path formed by the strong integration of BNNRs and EP. In addition, the electrical breakdown strength increased from 95.58 to 159.17 kV·mm−1 as the BNNRs content increased, while the nanocomposites maintained acceptable dielectric properties. The results indicate the potential for BNNRs as a new class of nanofiller for dielectric polymers.

No abstract