Mattia D, Bau H H, Gogotsi Y
Materials Science and Engineering Department and A.J. Drexel Nanotechnology Institute, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, USA.
Langmuir. 2006 Feb 14;22(4):1789-94. doi: 10.1021/la0518288.
The handling, dispersion, manipulation, and functionalization of carbon nanotubes and nanopipes often require the use of solvents. Therefore, a good understanding of the wetting properties of the carbon nanotubes is needed. Such knowledge is also essential for the design of nanotube-based nanofluidic devices, which hold the promise of revolutionizing chemical analysis, separation, drug delivery, filtration, and sensing. In this work, we investigated the wetting behavior of individual nanopipes produced by the chemical vapor deposition (CVD) of carbon in porous alumina templates and of thin carbon films produced by the same technique. The carbon pipes and films have the same chemistry and structure as determined by Raman and infrared spectroscopies and, when similarly treated, demonstrate the same qualitative wetting behavior, as determined by optical microscopy. Thus, measurements conducted on the carbon film surface are relevant to the nanopipes. In the case of the nanopipes, filling with various liquids was monitored. Contact angle experiments with both polar (water, glycerol, ethylene glycol, ethanol, tetra-hydro furan, and 2-propanol alcohol) and nonpolar liquids (cyclohexane, hexadecane, poly(dimethylsiloxane), and a fluoro-silicone) were conducted on films using the sessile drop method. The contact angles on the CVD carbon films ranged from 0 to 79 degrees. The exposure of the carbon films to a NaOH solution, typically used to dissolve the alumina template, led to a significant decrease of the contact angle, especially in the case of polar liquids.
碳纳米管和纳米管的处理、分散、操控及功能化通常需要使用溶剂。因此，需要深入了解碳纳米管的润湿性。此类知识对于基于纳米管的纳米流体装置的设计也至关重要，这类装置有望彻底改变化学分析、分离、药物递送、过滤及传感等领域。在本研究中，我们研究了通过在多孔氧化铝模板中进行碳的化学气相沉积（CVD）制备的单个纳米管以及通过相同技术制备的碳薄膜的润湿行为。通过拉曼光谱和红外光谱确定，碳管和碳膜具有相同的化学组成和结构，并且在经过类似处理时，通过光学显微镜确定它们表现出相同的定性润湿行为。因此，在碳膜表面进行的测量与纳米管相关。对于纳米管，监测了其用各种液体填充的情况。使用静滴法在碳膜上对极性液体（水、甘油、乙二醇、乙醇、四氢呋喃和异丙醇）和非极性液体（环己烷、十六烷、聚二甲基硅氧烷和氟硅氧烷）进行了接触角实验。CVD碳膜上的接触角范围为0至79度。将碳膜暴露于通常用于溶解氧化铝模板的NaOH溶液中会导致接触角显著减小，尤其是对于极性液体而言。
