Performance enhancement of nanoscale heat pipe with hydrophilic/hydrophobic pattern

As one of the most efficient cooling methods, heat pipe has been widely used in many fields. Yet, with the development of miniaturized devices, the study on heat pipe should be pushed to the nanoscale as well. In this paper, Molecular Dynamics simulation is adopted for the study of nanoscale heat pipe. To enhance the performance, heat pipe's hot and cold surfaces are applied with the hydrophilic/hydrophobic pattern separately. Firstly, samples with a uniform wettability surface are compared to demonstrate the superiority of hydrophilic/hydrophobic pattern. Afterwards, the effect of hydrophilic/hydrophobic pattern on the hot surface and cold surface is investigated separately. When the hot surface has the pattern, its evaporation rate is found to be higher because of the combined effects of hydrophilic and hydrophobic areas. As for the cold surface, its condensation rate will not reduce too much after introducing the pattern because the temperature is also a key factor. Lastly, it is found that strengthening the condensation by constructing nanopillar on the cold surface will not necessarily enhance the performance because the nanostructures will hinder the liquid circulation. Obtained results validate the positive effect of hydrophilic/hydrophobic pattern, offering conducive suggestions for the design principle of nanoscale heat pipe. © 2023 Elsevier Ltd