The intrinsic contact angle is an essential wetting parameter between a liquid and a substrate and had long been regarded as an intrinsic interfacial property. Recent investigations showed that the intrinsic contact angles depend on substrate curvatures. However, the reported trends were contradictory, and the underlying physics has not been revealed. This paper presents a molecular perspective to understand the intrinsic nature of the curvature effect on the contact angles. Molecular dynamics simulations quantitatively validate the theoretical model without fitting. This general molecular interaction model provides a unified curvature effect on different fluids that the contact angle decreases on a concave substrate and increases on a convex substrate. This curvature effect is amplified on a more wettable substrate and enlarged by a longer-range molecular interaction. We anticipate that the new understanding of nanoscale wetting will give new insights into the design of nano-flow systems and stable superhydrophobic surfaces.

固有接触角是液体和基材之间的基本润湿参数，长期以来一直被认为是一种固有的界面特性。最近的研究表明，固有接触角取决于基材曲率。然而，报告的趋势是矛盾的，潜在的物理原理尚未揭示。本文提出了一个分子视角来理解曲率对接触角影响的内在本质。分子动力学模拟无需拟合即可定量验证理论模型。这种通用的分子相互作用模型对不同的流体提供了统一的曲率效应，即接触角在凹基板上减小，在凸基板上增大。这种曲率效应在更易润湿的基材上被放大，并被更远距离的分子相互作用放大。我们预计，对纳米级润湿的新理解将为纳米流动系统和稳定的超疏水表面的设计提供新的见解。