Research progress on the mechanism and regulation of heat transport in solid-liquid interface such as engineering thermophysics

The thermal transport properties of the solid-liquid interface play a crucial role in the application of composite polymer materials, nanofluids, thermal management of electronic devices, and nanoparticle-assisted therapy. For example, the thermal conductivity of nanofluids may be much higher than the thermal conductivity of the corresponding liquid, so it is expected to be widely used in microelectronic devices, fuel cells, household refrigerators, air conditioning heat dissipation, chemical pharmaceuticals, automotive engines, hybrid vehicle thermal management, and boilers Flue gas cooling and other fields.

However, in nanofluids and other nanomaterials, the total surface area of ​​solid materials rapidly increases with the decrease of structural features, and the heat transport properties at the solid-liquid interface have a significant effect on the thermal transport properties of materials in practical applications. Therefore, the study of the interface heat transport mechanism and the regulation of the heat transport performance at the solid-liquid interface will play an important role in promoting the development of the above industries.

Based on the above background, recently, the Institute of Engineering Thermophysics, Chinese Academy of Sciences and the researchers of the University of Notre Dame have established a solid-liquid interface based on a femtosecond laser pump-probe experimental system. The thermal conductivity measurement system uses this system to measure the thermal conductance of a variety of solid and liquid materials. Solid materials include metallic aluminum and metallic gold. Liquid materials include water, alcohol, hexadecane, and paraffin.

Through the analysis of the solid-liquid interface thermal conductivity measurement results and the use of molecular dynamics simulation methods to calculate the thermal conductivity of the solid-liquid interface, the researchers conducted a systematic and detailed study of the mechanism and influencing factors of the solid-liquid interface heat transport, including solid The Influence of Liquid Interface Wettability and Molecular Vibration Dynamic Density Matching on the Heat Transport Performance of Solid - liquid Interface .

Based on experimental and theoretical guidance, researchers further tried to regulate the heat transfer properties of the solid-liquid interface. The researchers used molecularly autonomous techniques to prepare a series of self-assembled monolayers with similar molecular structures to liquid hexadecane on metallic gold surfaces, including thiol molecules with from 2 to 18 carbon atoms. These thiol molecules can form covalent bonds with metallic gold and have similar molecular dynamic density distribution with liquid hexadecane. Using this method, researchers have greatly improved the heat transport performance of the solid-liquid interface, and the interface thermal conductivity is maximized. Increase about 5 times. This method is expected to be applied to a wider range of industries and promote the practical application of micro/nano scale solid-liquid thermal management systems.

The above work was supported by the National Natural Science Foundation of China (No. 51336009). The research results have been published in Advanced Materials, an international magazine for materials science.

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