特殊浸润性纳米材料的制备及其在水下液滴输运中的应用

发布时间：2018-07-21 09:51

【摘要】：微液滴的操控因具有分析精确度高、环境污染小等优点而在微化学反应、生物分析、可控药物释放、无损液滴输运及纳米材料合成等方面得到广泛的应用。但现有的操控方式存在液滴的操控设备制造成本高、操作方式不灵活以及液滴自身的挥发等诸多问题,因此限制了微液滴操控技术的发展。针对上述问题,本研究利用超疏水或水下超疏油纳米材料对油滴进行吸附或包裹,然后分别利用磁、热、光等手段实现油滴在水中非接触的可控输运,并且利用这种油滴输运方式实现了水中不同种类有机试剂的高效快速混合与反应。本论文的研究成果将在水中微化学反应、微量成分分析等方面具有重要的应用前景。以聚苯乙烯(PS)微/纳米球作为模板,通过自组装和高温烧结制备三维多孔磁性Fe(Co或Ni)/C的复合材料。所得纳米复合材料无需低表面能物质处理而具有超疏水超亲油特性,能够快速的吸附水面不同种类油。在磁场的控制下,吸附了油的复合材料可以在水中自由输运,将水面的油带到水下,与水下的油滴接触,由此来实现水中不同密度有机物的有效混合。被吸附的油还能够在磁场控制下从水中移除,从而达到了油水混合物有效分离的目的。由于Fe(Co或Ni)/C复合材料具有较好的耐酸碱性,因此可以使这种磁控油滴输运方式适用于多种水环境。为了实现水下油滴向水上的垂直输运,本论文采用具有温度响应特性的Si O2(Fe_3O_4或PS)-PNIPAm纳米材料作为油滴输运工具。室温下,将纳米颗粒包裹在水下油滴表面形成一层紧密的包裹层。这层包裹的纳米颗粒能够使油滴与基底进行有效隔离,避免了因与基底的接触而对油滴带来的污染与损失。另外,这层包裹层能够有效的密封住通过调节水温而在油滴内产生的气泡。通过控制油滴内气泡体积的大小,实现了油滴向水上的可控输运,同时还实现了油滴在水中的多次往返运动。除此以外,利用具有磁性的Fe_3O_4-PNIPAm纳米材料还能够实现对液滴输运方向的调控。通过这种温控输运方式,本论文实现了在无外界作用力控制下水下的油滴(CHCl_3、CH_2Cl_2或CCl_4)与水面油滴(十二烷等)的有效混合。为了更加精确地控制液滴在水下的输运过程,采用具有光热转换特性的Fe_3O_4@聚多巴胺(PDA)核壳结构纳米材料对油滴进行包裹。该纳米材料是在碱性条件下将多巴胺聚合在Fe_3O_4纳米颗粒表面而得到。对包裹层进行近红外激光照射后,可通过控制近红外激光的照射条件,调节包裹油滴内气泡体积来达到液滴从水下向水上可控性输运的目的。这种利用激光来控制的液滴输运,可以实现液滴在水中的悬停、多次往返等操作。另外,在磁场作用下,油滴表面Fe_3O_4@PDA包裹层可以被可逆的打开与关闭,从而实现了水下油滴组成和体积的调控。这种光控的液滴操作方式将为水下智能微反应器的操作提供一种新颖简便的方法。
[Abstract]:Microdroplet manipulation has been widely used in micro-chemical reaction, biological analysis, controlled drug release, non-destructive droplet transport and synthesis of nanomaterials due to its advantages of high analytical accuracy and low environmental pollution. But there are many problems such as high manufacturing cost of droplet control equipment, inflexible operation mode and volatilization of droplet itself, which limit the development of micro-droplet control technology. In order to solve the above problems, the oil droplets were adsorbed or encapsulated by superhydrophobic or underwater super-hydrophobic nano-materials, and then the controllable transport of oil droplets in water was realized by magnetic, thermal and optical means, respectively. The oil droplet transport method was used to realize the efficient and rapid mixing and reaction of different kinds of organic reagents in water. The research results of this paper will have an important application prospect in micro chemical reaction and micro component analysis in water. Three dimensional porous magnetic Fe (Co or Ni) / C composites were prepared by self-assembly and high temperature sintering with polystyrene (PS) microspheres as template. The obtained nanocomposites have the characteristics of super hydrophobic and super oil-lipophilic without the treatment of low surface energy materials and can rapidly adsorb different kinds of oil on the water surface. Under the control of magnetic field, the oil-adsorbed composite can be transported freely in the water, and the oil on the water can be brought into contact with the oil droplets under the water, thus realizing the effective mixing of organic matter of different densities in the water. The adsorbed oil can also be removed from the water under the control of magnetic field, thus achieving the purpose of effective separation of oil and water mixtures. Because Fe (Co or Ni) / C composites have good acid and alkali resistance, this magnetically controlled oil droplet transport method can be used in many water environments. In order to realize the vertical transport of oil droplets to water, Sio _ 2 (Fe _ 3O _ 4 or PS) -PNIPAm nanomaterials with temperature response characteristics are used as oil droplet transport tools in this paper. At room temperature, nanoparticles are encapsulated on the surface of underwater oil droplets to form a close coating. The coated nanoparticles can effectively isolate the oil droplets from the substrate and avoid the pollution and loss of the oil droplets caused by contact with the substrate. In addition, this layer can effectively seal the oil droplet by adjusting the temperature of the bubble. By controlling the size of the bubble volume in the oil droplet, the controllable transport of the oil droplet to the water is realized, and the multiple round-trip movement of the oil drop in the water is also realized. In addition, the magnetic Fe3O4-PNIPAm nanomaterials can also be used to regulate the transport direction of droplets. In this paper, the effective mixing of CHCl3CHS2Cl2 or CCl4 and surface oil droplets (dodecane, etc.) under the control of no external force has been realized through this temperature-controlled transport mode. In order to control the transport process of droplets under water more accurately, the oil droplets were encapsulated with Fe3OStack4 @ PDA-Core-shell structure nanomaterials with photothermal conversion characteristics. The nanomaterials were prepared by polymerizing dopamine on the surface of Fe _ 3O _ s _ 4 nanoparticles under alkaline conditions. After the coating layer was irradiated by near infrared laser, the bubble volume in the package oil droplet could be adjusted by controlling the irradiation condition of the near infrared laser to achieve the purpose of the controllable transport of the liquid drop from the underwater to the water. This kind of droplet transport controlled by laser can realize the hovering of droplets in water and the operation of multiple round trips and so on. In addition, under the action of magnetic field, the envelope layer of the oil droplet surface can be reversible opened and closed, thus realizing the regulation of the composition and volume of the oil droplet under water. This light-controlled liquid droplet operation mode will provide a novel and simple method for the operation of underwater intelligent microreactor.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1

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