Production and Characterization of Block Carbon Nanotubes

碳纳米管独特的力学和电学性质使其在许多重要的当前和潜在的应用中得到了应用。其中许多应用依赖于纳米管外表面的化学官能化来改变其性质。所有以前的方法都涉及整个纳米管的功能化。在这里，我们正在建立商业可扩展的程序来修饰纳米管的片段，从而产生被称为块状纳米管的东西。由于缺乏大批量的制造技术，阻碍了块状纳米管的大规模生产。我们将展示嵌段纳米管在各种应用中的潜力，如聚合物回收、石油回收和生物质燃料生产。包括微电子、太阳能和生物材料在内的其他应用也可能受到影响。该研究项目将涉及代表性不足的群体的参与，主要是美洲原住民。将创建一个独特的博客来记录研究生在该项目中的工作经历，并向广大公众展示科学家的人性化面孔。通过展示这项研究是如何从头到尾进行的，该博客有望刺激学生在STEM学科中从事职业生涯。我们计划以商业可扩展的方式合成块纳米管；例如，两块纳米管将具有纳米管的一部分具有一种化学成分，另一部分具有第二种化学成分。将开发两种可扩展的方法来制造块状纳米管。在一种情况下，碳纳米管将被用作界面稳定剂(例如Pickering乳剂)，并且只有位于颗粒外部的管部件将被功能化。在另一种情况下，在含有浸渍了纳米管生长催化剂的平板的沸腾床中的合成条件将随着管的生长而改变以改变表面化学。前者要研究的基本方面包括管子长度与液滴大小的关系以及改进前的管子化学；对于后者，基本方面包括反应条件和原料气组成。通过透射电子显微镜和原子力显微镜来表征纳米管表面化学的空间变化。我们将测试这些管子作为聚合物/聚合物和油/水系统的界面稳定剂，以及在较高温度和压力下用作两相催化剂载体。

The unique mechanical and electronic properties of carbon nanotubes result in their use in many important current and potential applications. Many of these applications rely on the chemical functionalization of the outer surface of the nanotubes to modify their properties. All previous methods involved functionalization of the entire nanotube. Here, we are establishing commercially-scalable procedures to modify segments of the nanotube resulting in what are referred to as block nanotubes. The lack of a large-volume manufacturing technique has prevented the realization of mass production of block nanotubes. We will demonstrate the potential for block nanotubes to be used in various applications such as polymer recycling, oil recovery, and biomass fuel production. Other applications including microelectronics, solar energy and biomaterials could also be impacted. The research project will involve participation of underrepresented groups, primarily Native Americans. A unique blog will be created to document graduate students' experiences working on the project and present a human face of scientists to the broad public. By presenting how the research is carried out from "start-to-finish," the blog is expected to stimulate students into undertaking a career in STEM disciplines.We plan to synthesize block nanotubes in a commercially-scalable fashion; for example a diblock nanotube would have one fraction of the nanotube with one chemistry and the other fraction with a second chemistry. Two scalable methods to manufacture block nanotubes will be developed. In one case, carbon nanotubes will be used as interfacial stabilizers (e.g. Pickering emulsions) and only those tube parts on the outside of the particles will be functionalized. In the other case, synthesis conditions in a fluidized bed containing flat surfaces impregnated with nanotube growth catalyst will be altered to change the surface chemistry as the tubes grow. Fundamental aspects to be studied in the former include tube length relative to droplet size and tube chemistry prior to modification; for the latter, fundamental aspects include reaction conditions and feed gas composition. Characterizing the spatial variation of nanotube surface chemistry will be performed via transmission electron microscopy and atomic force microscopy. We will test these tubes as interfacial stabilizers in polymer/polymer and oil/water systems, as well as biphasic catalyst supports under higher temperatures and pressures.