固液界面纳米气泡生成及性质研究

发布时间：2018-03-18 14:26

本文选题：原子力显微镜　切入点：纳米气泡　出处：《上海师范大学》2012年硕士论文　论文类型：学位论文

【摘要】：溶液中存在着纳米气泡的提出源于研究两个疏水固体浸入水中时存在着的长程引力。而最先获得的纳米气泡的图像来自于扫描电镜，称为原子力显微镜的轻敲模式（在不断振动的悬臂上粘附着一个传统的AFM探针并浸入水中对样品进行扫描），因为AFM的接触模式探针与样品间的作用力太大而不适合对软的物质进行成像。从那以后，纳米气泡在各个领域引起了广泛关注。为了用AFM对纳米气泡进行成像，通常使用较为平整的基底，包括：高序热解石墨（HOPG），，云母，金，聚苯乙烯薄膜，以及修饰过的硅。而为了在这些基底上产生纳米气泡，应用了以下方法：直接浸渍法，两种溶剂替换以及快速加热，电化学法等。其中，醇水替换被广泛应用并被证明是能在不同的基底上产生大量纳米气泡的重复性好的方法。同样，也能使用其它有机溶剂与水替换来产生纳米气泡。然而，有机溶剂与水的替换存在着一些局限性，比如：这种方法不能应用在一些重要的可溶于有机溶剂的基底上，例如有机涂料或生物膜。在纳米气泡的研究中一个重要的问题是如何在一定的基底上生成足够多的纳米气泡。醇水替换能够生成纳米气泡是因为乙醇中含有的溶解气体比水中的溶解气体多。然而这一机制是否也适用于水与含溶解气体低于水的液体替换却并不知道，如水与盐溶液的替换。在本论文中，主要在HOPG表面应用不同浓度的盐溶液来替换水，发现水-盐水替换确实能生成纳米气泡。即使与水替换的盐的浓度低到0.15M也同样能生成纳米气泡，且得到的纳米气泡随所使用的盐浓度的增加而增加。当所用的盐的浓度高于2.00M时，所得以的纳米气泡的密度基本保持不变。且纳米气泡的一些性质，如能够合并，接触角为164°左右等性质与其他研究者所到的纳米气泡的性质一致。实验还证实了纳米气泡能存在于乙醇中，之前认为纳米气泡只能存在于水中。此外，还发现把新解离的HOPG在空气中搁置一段时间后浸入水中就能产生纳米气泡，气泡的量随搁置时间的增加而增加。此外，还应用同步辐射的软X射线对纳米气泡进行了研究，其结果证实存在纳米气泡。
[Abstract]:The existence of nano-bubbles in the solution is derived from the study of the long-range gravity of two hydrophobic solids when they are immersed in water, and the first images of the nano-bubbles are obtained from the scanning electron microscope (SEM). A tap mode called an atomic force microscope (attached to a traditional AFM probe on a vibrating cantilever and immersed in water to scan the sample because the force between the probe and the sample in the AFM contact mode is too great to feel comfortable). Imaging of soft matter. From then on, Nanobubbles have attracted wide attention in various fields. For the purpose of imaging nano-bubbles with AFM, a relatively flat substrate is usually used, including high-order pyrolytic graphite HOPG, mica, gold, polystyrene films, and modified silicon. The following methods were used: direct impregnation, two solvent substitution, rapid heating, electrochemical methods, etc., Alcohol water substitution is widely used and has been shown to be a reproducible method for producing large numbers of nanometer bubbles on different substrates. Similarly, other organic solvents and water can be used to produce nano bubbles. There are some limitations in the substitution of organic solvents with water. For example, this method cannot be applied to some important solvent-soluble substrates, such as organic coatings or biofilms. An important problem in the study of nano-bubbles is how to generate enough nano-bubbles on a certain substrate. The substitution of alcohol and water can produce nano-bubbles because the dissolved gas in ethanol is more than the dissolved gas in water. However, it is not known whether this mechanism also applies to the substitution of water with liquids containing dissolved gases below water. In this paper, different concentrations of salt solution are used to replace water on the surface of HOPG. It has been found that water-salt replacement does produce nano bubbles. Even if the concentration of salt replaced by water is as low as 0. 15m, it can also form nano bubbles. When the concentration of salt used is higher than 2.00m, the density of the resulting nano-bubble remains basically unchanged, and some properties of the nano-bubble, such as being able to merge, are obtained. The contact angle of 164 掳is the same as that of other nano-bubbles. The experiment also confirmed that nano-bubbles can exist in ethanol, which was previously thought to exist only in water. In addition, it was also found that the newly dissociated HOPG can be used in the air for a period of time and then immersed in water to produce nano-bubbles. The amount of bubble increases with the increase of shelving time. In addition, the synchrotron radiation soft X-ray is used to study the nano-bubble, and the results show that there are nano-bubbles.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.08

【相似文献】