利用多體耗散粒子動力學法模擬雙成分互溶的奈米液滴在平滑表面上的濕潤行為。研究中發現楊式方程式僅可以使用於純物質的奈米液滴，而利用在雙成分液滴時，楊式方程式會失效。發現在雙成分系統下，實際測量奈米液滴的接觸角會大於利用楊式方程式所預測的楊式接觸角。隨著組成成分越接近純物質，其誤差值會逐漸下降。另外，若雙成分之間的互溶性增加，其誤差值也會隨之下降。失效的楊式方程式與奈米液滴及奈米薄膜的尺寸效應有關係，隨著奈米液滴的半徑增加，實際的接觸角則會下降並趨近於宏觀系統中的楊式接觸角。相同的，界面張力也會隨著奈米薄膜的厚度增加而下降，並趨近於宏觀系統的定值。在奈米系統下，尺寸效應所影響的界面組成造成的界面張力改變，是造成雙成分系統下，楊式方程式失效的原因。;The wetting behavior of a nanodroplet containing two miscible liquids on a smooth substrate is explored by many-body dissipative particle dynamics simulations. It is found that Young’s equation is valid for nanodroplets of pure fluids but fails for binary nanodroplets. The actual contact angle (CA) is always larger than the Young’s CA, and their difference is getting smaller as the composition approaches pure fluids or the compatibility of the mixture is increased. The failure of Young’s equation is closely associated with the size-dependent behavior in binary nanodroplets and nanofilms. As the nanodroplet size is increased, the actual CA is found to decline but approaches a constant expected in macroscopic systems. Similarly, as the nanofilm thickness is increased, surface tension decreases and reaches its macroscopic value. The change of surface tension is attributed to the size-dependent surface composition, which is responsible for the failure of Young’s equation.
