Mechanical Flexibility Improves Thermal Conduction of Confined Liquid in Nanofluidics

Nanofluidics systems demonstrate the potential to address the thermal management challenge in nanoelectronics devices with extraordinary transport properties. However, the phonon features in different substrates have led to contradictory thermal transport properties of the confined liquid. Understanding the correlation between the thermal transport of nanoconfined liquid and substrate vibration is of critical importance. Herein, we demonstrate that the phonon resonance between the substrates and the confined water molecules can significantly enhance the thermal conductivity of the water. Detailed analyses reveal that the phonon resonance shortens the lifetime of hydrogen bonds, promotes the mobility of the water molecules, and enhances the thermal conductivity. Moreover, the effect of phonon resonance is more pronounced with a reduced channel size owing to stronger solid-liquid interactions. These results and findings offer a fundamental understanding of the thermal transport of the nanoconfined liquid and provide theoretical guidance for developing nanofluidics-based cooling strategies.