Mechanism of Vapor-Liquid Phase Transition under Synergistic Effects of Nanoscale Potential Energy and Cavitation

Liquid evaporation at the nanoscale is significantly enhanced by microscopic effects, with its rate even exceeding the predicted upper limit of the classical HertzKnudsen equation. This property makes nanoscale liquid evaporation highly valuable for applications in solar-driven interfacial evaporation, electronics cooling, and microfluidics. However, existing research predominantly focuses on the influence of individual microscopic effects, leaving the synergistic mechanisms of multiple effects poorly understood. To deeply reveal the microscopic mechanism of liquid phase change at the nanoscale, this study employs liquid argon as a model system to systematically investigate the synergistic effect of potential energy and cavitation on its evaporation. Using molecular dynamics simulations, we studied the evaporation process of liquid argon within nanochannels characterized by different solid-liquid interaction strengths under identical temperature and time frames. The results indicate that an increase in the solid-liquid interaction strength reduces the average potential energy of liquid argon and increases the evaporation energy barrier, which theoretically should suppress evaporation. Nevertheless, the capillary pressure induced by the increased meniscus curvature leads to negative pressure within the liquid argon, triggering a cavitation effect. This cavitation generates bubbles inside the liquid argon, which significantly increases the evaporation surface area and consequently promotes evaporation. Furthermore, the meniscus-dominated evaporation mode is gradually weakened, while the contribution from cavitation bubbles becomes increasingly pronounced. This study demonstrates that the evaporation rates of liquid argon in the four nanochannels with different interaction strengths are 3.49×10⁻¹⁴ kg/s, 3.95×10⁻¹⁴ kg/s, 3.02×10⁻¹⁴ kg/s, and 2.44×10⁻¹⁴ kg/s, respectively. Therefore, it is concluded that the evaporation rate does not vary linearly with increasing solid-liquid interaction strength. Instead, the synergistic state between potential energy and the cavitation effect is optimized at a medium interaction strength, leading to a maximum evaporation rate.