GOALI: Generation, Characterization, and Modeling of Structure and Properties of Polymer Blend Nano- and Microparticles

9982077Otaigbe这个GOALI奖，由Div.材料研究局和数学和物理科学局多学科活动办公室的研究领域是纳米科学。 当聚合物被限制在一个分子大小的小液滴或分子聚集体中时，新的动力学行为出现了。 溶剂蒸发在足够短的时间尺度上发生以阻止相分离，产生在分子尺寸内均匀的干燥纯聚合物或聚合物共混物微粒。 这种能力允许简单地通过调节溶液中聚合物的相对重量分数来生产具有可调性质（例如折射率）的球形聚合物合金微粒。 这项研究将开发一种方法，用于生成聚合物和聚合物共混物微粒，并用于探测聚合物微米和纳米颗粒的结构，形态和其他特性。 使用仪器开发的探测单荧光分子在亚微米液滴，该提案将证明，几乎任意大小和组成的聚合物颗粒可以制成窄尺寸分散。 虽然这项研究的重点是聚合物系统，但微粒发生器可以很容易地适应制造小的有机和无机颗粒（以及混合系统）。 一些光学方法，如夫琅和费衍射，荧光，和传统的相差显微镜将被用来探测固定在二维基板上的聚合物颗粒或悬浮在空间中使用三维四极（保罗）陷阱。 光学衍射方法将提供一个独特的外观（现在用常规方法如电子束显微镜是不可能的）在几毫秒的测量时间表内测量聚合物颗粒内部，使其对在线生产应用具有吸引力。所获得的知识将用于解决相分离，从溶液中的本体不混溶组分生产许多技术上相关和科学上令人感兴趣的均相聚合物共混物的主要障碍。 聚合物微粒的应用领域的实例包括聚合物共混物或合金、用于药物递送系统的生物材料、电光和发光器件、聚合物粉末喷涂、以及复合材料中和聚合物支撑的多相催化中无机纤维的聚合物粉末浸渍。

9982077OtaigbeThis GOALI award, jointly supported by the Div. of Materials Research and the Office of Multidisciplinary Activities of the Directorate for Mathematical and Physical Sciences, is in the area of nanoscience. New dynamic behavior emerges when polymers are confined in a small droplet of solution the size of a molecule or in molecular aggregates. Solvent evaporation takes place on a time scale short enough to frustrate phase separation, producing dry pure polymer or polymer blend microparticles that are homogeneous within molecular dimensions. This capability allows production of spherical polymer alloy microparticles with tunable properties (such as refractive index) simply by adjusting the relative weight fractions of the polymers in solution. This research will develop a methodology for generating polymer and polymer blend microparticles and for probing the structure, morphology, and other characteristics of the polymer micro- and nanoparticles. Using instrumentation developed for probing single fluorescent molecules in submicrometer droplets, the proposal will demonstrate that polymer particles of nearly arbitrary size and composition can be made with narrow size dispersion. While the focus of this research is on polymeric systems, the microparticle generator can be easily adapted to make small organic and inorganic particles (and hybrid systems). A number of optical methodologies such as Fraunhofer diffraction, fluorescence, and conventional phase-contrast microscopy will be used to probe polymer particles immobilized on two-dimensional subrstrates or levitated in space using a three-dimensional quadrupole (Paul) trap. The optical diffraction method will provide a unique look (not possible now with conventional methods such as electron-beam microscopy) inside a polymer particle in a measurement time schale of a few milliseconds, making it attractive to in-line production applications.The knowledge gained will be useful in addressing phase separation, the primary barrier to producing many technologically relevant and scientifically interesting homogeneous polymer blends from bulk-immiscible components in solution. Examples of application areas of the polymer microparticles include polymer blends or alloys, biomaterials for drug delivery systems, electro-optic and luminescent devices, polymer powder spray coating, and polymer powder impregnation of inorganic fibers in composites and in polymer-supported heterogeneous catalysis.