Development and Study of Self-Assembled Microthermometers

远程访问的微温度计对于测量和研究各种热传递过程非常有兴趣，包括生物技术，微反应器，微流体，环境研究等。目前，各种染料、颜料、微胶囊染料和液晶被用于绘制散装流体中的温度。所有这些染料和微粒都有严重的局限性：要么温度敏感性很小，要么工作温度范围太窄，它们可能污染使用它们的介质，而且/或者温度信号可能与介质化学可能发生的变化产生的信号混淆。在这里，我们建议开发一种新型的胶体荧光二氧化硅颗粒，它将能够“测量”环境的温度，并且不会出现上述问题。温度将作为粒子荧光的函数得到。为了制造这样的粒子，我们建议使用最近发现的自组装微米尺寸的纳米多孔二氧化硅胶体。荧光分子将被封装在这些粒子的圆柱形纳米通道内。这种粒子/探测器可用于研究液体和环境中的温度和输运现象。荧光染料在纳米通道有效的一维受限几何中的光学行为的研究也是一个基本的兴趣。除了增强了温度敏感性外，我们的初步研究表明，一些荧光染料的封装导致了相当高的荧光，例如，比最近报道的嵌入量子点的类似大小的聚合物颗粒的荧光高170-300倍。这使得这些粒子成为有史以来合成的最亮的荧光珠。因此，所提出的微型温度计将很容易追踪。智力价值：这项研究的发现将导致新型超亮荧光粒子的发展和理解，这种荧光粒子将用作微米尺寸的温度计。每个这样的温度计都可以通过测量这些粒子发出的荧光来远程访问。荧光染料的光学行为在一个有限的明确的几何纳米通道将被研究。我们将研究包封染料后温度敏感性增强的性质。这将允许开发灵敏度，可重复性和稳定性优化的微型温度计。更广泛的影响：微温度计将用于研究和工业应用，这些应用需要研究大量透明介质中的温度分布和流动。预计这项研究将对社会产生重大影响。粒子的视觉外观和迷人的内部结构将有助于赢得公众演讲和吸引人的出版物。这项研究的结果将通过互联网、专业出版物、通俗文学传播，并将在包括学生会议在内的会议上发表。这将通过向他们展示科学研究所能提供的真正的兴趣和兴奋，帮助更多的美国学生接触科学。变革性质：拟议的微型温度计有望用于各种各样的应用：作为“智能灰尘”，用于绘制温度场，以优化热流，最大限度地减少建筑物，办公室，工厂的能量损失，优化能耗制造过程等；作为固体中的温度标签，为固体表面带来高能光束（如激光）相互作用的基本理解。此外，由于外部是二氧化硅，这些颗粒在生物学上是良性的，因此它们可以用于需要可视化器官和材料温度分布的生物医学应用。最后，微型温度计将用于研究亚微米范围内的传热，这对能量转换，生物技术，微电子和生化检测具有持续的重要性。

CBET-0755704SokolovRemotely accessed microthermometers are of great interest for measuring / studying various thermal transport processes, including biotechnology, microreactors, microfluidics, environmental study, etc. At the present time, various dyes, pigments, microencapsulated dyes, and liquid crystals are used to map the temperature in bulk fluid. All these dyes and particulates have serious limitations: either rather small temperature sensitivity or too narrow working range of temperatures, they can contaminate the medium in which they are being used, and/or the temperature signal can be confused with the signals from a possible change of the medium chemistry.Here we propose to develop a novel class of colloidal fluorescent silica particles which will be able to "measure" the temperature of the environment, and which will be free from the problems listed above. The temperature will be obtained as a function of the fluorescence of the particles. To make such particles, we propose to use recently discovered self-assembled micron-sized nanoporous silica colloids. Fluorescent molecules will be encapsulated inside the cylindrical nanochannels of those particles. Such particles/detectors can be used to study temperature and transport phenomena in both liquids and the ambient environment. The study of the optical behavior of fluorescent dyes in effectively one-dimensional confined geometries of nanochannels is also of fundamental interest. Apart from the enhanced temperature sensitivity, our preliminary study shows that encapsulation of some fluorescent dyes results in a rather high fluorescence, which is, for example, 170-300 times higher than fluorescence of similar-sized polymeric particles with embedded quantum dots reported recently. This makes these particles the brightest fluorescent beads ever synthesized. Thus, the proposed microthermometers will be easily traceable.Intellectual Merit: findings of this study will result in the development and understanding of novel ultra-bright fluorescent particles that will act as thermometers of micron size. Each such thermometer will be remotely accessible by measuring the fluorescent light radiated by these particles. Optical behavior of fluorescent dyes in a confined well-defined geometry of nanochannels will be studied. We will study the nature of the enhancement in temperature sensitivity after encapsulating the dyes. This will allow development of the micro-thermometers optimized for sensitivity, repeatability, and stability.Broader impact: Microthermometers will be used for both research and industrial applications which require studying temperature distributions and flows in a bulk of transparent media. The proposed research is expected to have a high impact on society. Great visual appearance of the particles and fascinating internal structure will help to make winning public presentations and attractive publications. The results of this research will be disseminated over the Internet, professional publications, popular literature, and will be presented at conferences, including student conferences. This will help to bring more American students to science by showing them the real interest and excitement that scientific research can provide.Transformative nature: The proposed microthermometers are expected to be used in a broad variety of applications: as "smart dust" for mapping temperature fields to optimize the heat flows to minimize energy losses in buildings, offices, factories, optimizing energy-consuming manufacturing processes, etc; as temperature tags in solids to bring fundamental understanding of the interaction of energetic beams, such as lasers, for the solid surfaces. Furthermore, being silica on the outside, these particles will be biologically benign, so they can be used in biomedical applications that require visualization of the temperature distributions in organs and materials. Finally, the microthermometers will be used to study heat transfer at the scales down to the submicron range, which is of continuing importance to energy conversion, biotechnology, microelectronics, and biochemical detection.