- 學位論文
水在磷烯奈米通道的毛細作用：表面結構的影響
Water Wicking in 2-dimensional Phosphorene Nanochannel: Effect of Surface Texture
摘要
我們將運用分子動力學方法，探索水在由二維磷烯製成的納米通道中的毛細動力學行為。首先，我們研究在奈米尺度下水滴在磷烯薄片上的部分濕潤行為，發現水滴在開始潤濕後，其潤濕面積(A)和內能(△E)遵循冪定律，潤濕面積與時間的二分之一次方成正比，內能則與時間的負二分之一次方成正比。此外，在受限奈米管道內的水栓模擬中測量拉普拉斯壓力(Laplace pressure)和平衡接觸角(equilibrium contact angle)，確認楊-拉普拉斯方程(Young-Laplace equation)在納米尺度上的適用性。在毛細管模擬實驗中，對於寬度為多層(N)磷烯薄片的通道中，觀察水自發得浸潤行為，並發現滲透長度和內能變化都與時間的二分之一次方成正比。然而，在狹窄的奈米通道(N = 2 ~ 5)中，滲透速率取決於管壁的表面結構(拱橋狀和鋸齒狀)。隨著板寬增加，這種影響效應逐漸減弱。我們觀察到除了N = 1之外，隨著板寬寬度增加，滲透速率隨之下降，這與Washburn’s equation預測方向相互矛盾。與由光滑的石墨烯製作而成的奈米通道相比，磷烯基通道的滲透速率較低。但是，隨著通道寬度增加，這種差異逐漸減小，這結果表示表面粗糙度對於較大的通道寬度影響變得不那麼顯著。
並列摘要
The imbibition dynamics of water in a nanochannel made of the two-dimensional phosphorene is explored using Molecular Dynamics. The partial wetting behavior of water nanodroplets on phosphorene sheets is examined first. The initial spreading of the wetted area (A) and internal energy (△E) are found to follow the power law, A ~ t1/2 and △E ~ -t1/2. Additionally, the Laplace pressure and equilibrium contact angle, determined from water plugs confined within nanoslits, verify the applicability of the Young-Laplace equation at the nanoscale. For water wicking in channels with a width of N layers of phosphorene sheets, the rate of change of both the penetration length and internal energy is proportional to t1/2. However, the imbibition rate in narrow nanoslits (N = 2 ~ 5) depends on the orientation (armchair and zigzag) of walls. This effect gradually diminishes as N increases. It was observed that, except for N = 1, the imbibition rate decreases with increasing channel width, which contradicts the prediction of Washburn’s equation. Compared to smooth graphene-based channels, the imbibition rate is lower in phosphorene-based channels. Nonetheless, this difference decreases as the channel width increases, suggesting that the impact of surface roughness becomes less pronounced with larger channel widths.