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

[9982077]该奖项由材料研究部和数学与物理科学理事会多学科活动办公室联合支持，涉及纳米科学领域。当聚合物被限制在一个分子大小的小液滴溶液或分子聚集体中时，新的动态行为就出现了。溶剂蒸发在足够短的时间尺度上进行，以阻碍相分离，产生干的纯聚合物或聚合物混合微粒，这些微粒在分子尺寸上是均匀的。这种能力允许生产具有可调性能的球形聚合物合金微颗粒（如折射率），只需调整溶液中聚合物的相对重量分数。本研究将开发一种生成聚合物和聚合物混合微粒的方法，并用于探测聚合物微粒和纳米粒子的结构、形态和其他特征。利用用于探测亚微米液滴中单个荧光分子的仪器，该提案将证明几乎任意大小和组成的聚合物颗粒可以用窄尺寸分散。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于制造小的有机和无机粒子（和混合系统）。许多光学方法，如弗劳恩霍夫衍射、荧光和传统的相对比显微镜，将用于探测固定在二维底物上或使用三维四极（保罗）陷阱悬浮在空间中的聚合物颗粒。光学衍射方法将在几毫秒的测量时间内提供聚合物颗粒内部的独特外观（现在使用电子束显微镜等传统方法是不可能的），使其对在线生产应用具有吸引力。所获得的知识将有助于解决相分离问题，这是从溶液中的大块不混相组分中生产许多技术相关和科学上有趣的均相聚合物混合物的主要障碍。聚合物微粒的应用领域包括聚合物共混物或合金、用于药物输送系统的生物材料、电光和发光装置、聚合物粉末喷涂涂层、复合材料和聚合物支持的非均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.