The extended thin-film region adjacent to the contact line is crucial in heat transfer because of its capability to enhance heat transfer and its critical role in wetting dynamics. The present investigation focused on the study of advancing contact line morphology induced by water vapor condensation. The condensation was at low rates with the advancing velocities <60 nm/s. Two modes of atomic force microscopy were utilized to measure the morphology of a liquid film with the nanometer resolution. The results indicated that the profile of the film went straight down to the apparent contact line when viewed in a sub-micron window, which is in contrast to nonvolatile cases, such as glycerol and silicon oil, which would have a convex nanobending around 20 nm from the substrate surface due to the local dynamic friction. Furthermore, a precursor nanofilm was detected beyond the contact line during condensation, and nanodroplets hundreds of nanometers in height were sitting on the nanofilm, representing the structure of the advancing contact line, and being adjacent to the condensation plays an essential role in contact line dynamics.

中文翻译：

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冷凝过程中前进接触线附近薄液膜的纳米级形态

与接触线相邻的扩展薄膜区域在传热中至关重要，因为它具有增强传热的能力及其在润湿动力学中的关键作用。本研究的重点是研究由水蒸气冷凝引起的前进接触线形态。凝结速度低，前进速度 <60 nm/s。两种模式的原子力显微镜被用来测量具有纳米分辨率的液膜的形态。结果表明，当在亚微米窗口中观察时，薄膜的轮廓直接下降到明显的接触线，这与甘油和硅油等非挥发性情况形成对比，后者在 20 nm 左右具有凸起的纳米弯曲由于局部动摩擦而从基材表面脱离。此外，