本研究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，此奈米液滴是由部分潤濕液及完全潤濕液所組成。隨著改變不同的混合物組成，可以確定奈米液滴的三種潤濕狀態：(I)完全潤濕，(II)部分潤濕伴隨有限前驅膜，以及(III)部分潤濕。雙成分液滴在狀態(I)中總是自發性擴散，而在狀態(III)中其接觸角隨著組成單調變化。然而，在狀態(II)中，無論組成如何改變，接觸角皆保持不變。此時的液滴形態呈現荷包蛋狀(球帽外環繞有限前驅膜)，透過組成分析發現在蛋白及蛋黃區內皆維持特定組成。儘管兩種液體之間的親和力很強，但在狀態(II)中，總有一些完全潤濕液會從球帽中逸出至前驅膜，即所謂的滲漏現象。此外這種非典型現象伴隨著球帽和前驅膜之間的化學勢平衡。與滲透平衡類似，凡得瓦分離壓力在前驅膜中提供了額外的貢獻。最後，探討了部分潤濕液的分子大小和兩種液體之間的親和力對洩漏現象的影響。;The wetting behavior of a nanodroplet which is a binary homogeneous mixture of partial and total wetting liquids on a smooth substrate is investigated by many-body dissipative particle dynamics. Dependent on the mixture composition, three wetting states of the nanodroplet can be identified: (I) total wetting, (II) partial wetting with precursor film, and (III) partial wetting. The binary droplet always spreads spontaneously in regime (I), while its contact angle (CA) changes with the composition monotonously in regime (III). However, in regime (II), the CA remains a constant regardless of the composition. The droplet morphology exhibits the fried-egg shape, a spherical cap surrounded by a precursor film. The compositions in both regions are unaltered in plateau regime. Although the affinity between the two liquids is strong, some of the total wetting liquid always escape from spherical cap to precursor film in regime (II), so-called leak-out phenomenon. Moreover, this atypical phenomenon accompanied by an equilibrium of chemical potential between the spherical cap and the precursor film. Similar to the osmotic equilibrium, the van der Waals disjoining pressure provides an extra contribution in the thin precursor film. Finally, the influences of the molecular size of the partial wetting liquid and the affinity between the two liquids on the leak-out phenomenon are examined.
