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Abstract The wetting characteristics of fluids play a crucial role in various fields of interface and surface science. Contact angle serves as a fundamental indicator of wetting behavior. However, accurate quantification of wetting phenomena even at the macroscale often poses challenges, particularly due to the hysteresis between receding and advancing contact angles. The complexity increases further at the nanoscale, where the significant volume of the interphase region causes ambiguity in defining the “dividing surface.” In this study, we use molecular dynamics simulations to investigate the wetting dynamics of a “cylindrical nanodroplet” and an argon nanofilm. Through analysis of microscopic density distribution maps and tension tensor distributions within the Gibbs framework, we identified equimolar and tension surfaces at both liquid-gas and liquid-solid interfaces. Our results show over 10% discrepancies between equilibrium contact angles calculated for equimolar surfaces and those based on tension surfaces in the case of the cylindrical nanodroplet. We observed a clear dependence of wetting contact angles on the cross-sectional radius of cylindrical droplets with a straight three-phase contact line. As the radius decreases, the differences between contact angles at equimolar and tension surfaces increase, while for larger droplets, these differences diminish and become negligible.

Abstract This paper investigates thermal transport in a nanocomposite system consisting of a porous silicon matrix filled with ionic liquid. Firstly, the thermal conductivity and heat capacity of two imidazolium and one ammonium ionic liquids were evaluated using the photoacoustic approach in piezoelectric configuration and differential scanning calorimetry, respectively. Then, the thermal transport properties of the composite system "ionic liquid confined inside porous silicon matrix" were investigated with the photoacoustic approach in gas-microphone configuration. The results demonstrated a significant enhancement of the thermal conductivity of the composite system when compared to the individual components, i.e. (i) more than two times for pristine porous silicon and (ii) more than eight times for ionic liquids. These results provide new paths for innovative solutions in the field of thermal management, particularly in the development of highly efficient energy storage devices.