The influences of interactions between copper plate and nano-water droplets on wettability with different solid–liquid potential parameters were studied, and the spread of droplets was compared and analyzed using the molecular dynamics method. The diameter of droplet spreading and the amount of water molecules adsorbed on the copper gradually increased with the potential parameters, whereas the absolute potential energy value between copper and water also increased. Negative potential energy represents the attraction force between solid atoms and liquid molecules, and the attraction grows stronger with the large absolute value of negative potential energy. The heat transfer performance of the wettability surface can be explained by analyzing the force of solid and liquid from the perspective of energy. These results are of great significance for establishing the wettability model of a smooth plate correctly and the design and manufacture of a special functional surface.

Boiling heat transfer on nanostructured surfaces presents great potential in cooling highly integrated microelectronic devices. Analysis of the factors affecting boiling heat transfer included the analysis of nanostructure and wettability, indicating that consideration of the influence of working liquid quantity is essential in finite spaces. Rapid boiling water films with various thicknesses placed on the same nanochannel copper plate were studied via molecular dynamics (MD) simulations. The simulation results reveal that the potential energy difference in the vapor–liquid coexisting region on the nanochannels was lower for thicker films, and the evaporation rate was lower. The effect of water film thickness on boiling heat transfer is closely related to the potential energy difference in the vapor–liquid coexisting region on the nanochannels. The heat transfer effect was the worst in case 1, where the water thickness was lower than the height of the nanochannels. This is because there is no guaranteed liquid replenishment at the nucleation points, although the potential energy difference was greatest in the vapor–liquid coexistence zone of case 1. Evaporation was the greatest in case 2, where the water film just covered the nanochannels because of the larger potential energy difference and sufficient liquid water replenishment. This study is of great significance for the analysis of the vapor–liquid flow mechanisms of micro/nanostructured surfaces and the improved design of thermal management equipment of micro/nano devices.

In this study, static contact angle measurement experiments were conducted on smooth copper surface and microchannel structure surfaces under different droplet sizes. The results showed that shallow processing will more easily lead to the deformation of the processed interface. And the wettability of the microchannel surfaces with the same width and different depth were obviously different. Moreover, the contact angles on three microchannel surfaces were almost the same when the size of droplet was 12μl duo to action of gravity. The optimal droplet size is 9μl to measure contact angle in this study.