NER: Large Scale Synthesis and Assembly of Micro- and Nanoparticles with Dipolar Charge and Anisotropic Shape

摘要CTS-0403462O。具有特定方向相互作用的微米和纳米尺寸的聚合物颗粒可以组装成先进的“智能”材料和消费品，但此类颗粒迄今还不容易获得。本文推广了两种大规模合成具有各向异性电荷或形状的新型聚合物粒子的新技术。第一类粒子将具有永久性偶极和/或四极矩。合成技术是基于乳液和微乳液在恒定或交变电场存在下的聚合(或固化)。这些粒子将表现出偶极-偶极相互作用，这将使它们在方向上自组装成具有远程取向的结构。将制造的第二类新颗粒是圆柱形聚合物微棒。PI已经发现了一种可扩展的工艺，通过剪切和“干燥”聚合物溶液中的乳化液滴来制造这种圆柱形颗粒。不同长宽比的胶体棒的制备将允许控制它们的取向、熵和诱导的偶极相互作用。这些各向异性粒子将用于组装各种先进材料，如离子和pH敏感凝胶、胶体液晶、具有特殊对称性的光子晶体和电流变流体。扩展了两个原始的概念，用于制造具有基本新颖的性质和相互作用的新的粒子类别。水中电各向异性粒子之间的方向相关的非DLVO表面力可能会引起广泛的学术和工业研究人员的兴趣。对这些粒子的接触可能会带来对非DLVO作用力的新的基本见解。棒状粒子使得对新的熵自组织现象的基础研究成为可能。通过对这些粒子进行工程组装，将形成新型的微结构和纳米结构。这些结构包括来自粒子而不是分子的“胶体”液晶，具有新对称性的光子晶体，强相互作用的水基电流变流体，以及粒子在其环境变化中组装或分解的材料。该项目将首次实现大规模、高效和廉价地制造具有各向异性形状和/或定向相互作用的胶体颗粒。还计划开展本科生研究项目，为工业科学家开设外展课程，以及开展国内和国际合作。由此产生的新材料和技术的潜在受益者包括化学、制药和生物医学行业，以及制造显示器、光电子和光电子设备的公司。一些可能的应用是在价值数百万美元的工业中，例如用胶体液晶取代显示器中的分子液晶，以及开发具有更高粘度和更好光学性能的新型聚合物“乳胶”涂料。光子晶体和水基电流变液可以在新兴的高科技中得到应用。还可以制造用于医疗应用的新型“智能”离子敏感或生物分子敏感凝胶。这将导致纳米级的可扩展和高效的制造过程。

AbstractCTS-0403462O. Velev, North Carolina State UniversityMicro- and nanometer sized polymer particles possessing specific directional interactions can be assembled into advanced "smart" materials and consumer products, however such particles are not readily available to date. Two new techniques for large-scale synthesis of novel classes of polymer particles with anisotropic charge or shape are extended here. The first class of particles will have permanent dipolar and/or quadrupolar moments. The synthesis technique is based on polymerization (or solidification) of emulsions and microemulsions in the presence of constant or alternating electric field. These particles will exhibit dipole-dipole interactions that will make them directionally self-assemble into structures with long-range orientation. The second new class of particles that will be fabricated are cylindrical polymer microrods. The PI has discovered a scalable process for making such cylindrical particles by shearing and "drying" of emulsified droplets from polymer solution. Fabrication of colloid rods of different aspect ratios will allow controlling their orientational, entropic and induced dipolar interactions. These anisotropic particles will be used for the assembly of a variety of advanced materials such as ion- and pH sensitive gels, colloidal liquid crystals, photonic crystals of uncommon symmetry and electrorheological fluids.Intellectual merit of the proposed activity. Two original concepts for fabrication of new classes of particles with fundamentally novel properties and interactions are extended. The orientation dependent non-DLVO surface forces between electrically anisotropic particles in water could be of interest to a wide community of academic and industrial researchers. Access to these particles could lead to new fundamental insights into non-DLVO forces. The rod-like particles make possible fundamental research in new phenomena of entropic self-organization. New types of micro- and nanostructures will be formed by engineered assembly of these particles. These structures include "colloidal" liquid crystals from particles instead of molecules, photonic crystals with novel symmetries, strongly interacting water-based electrorheological fluids and materials where the particles assemble or disassemble in response to changes in their environment.Broader impacts resulting from the proposed activity. This project will for the first time allow the large-scale, efficient and inexpensive fabrication of colloidal particles with anisotropic shape and/or directional interactions. Undergraduate student research projects, an outreach course for industrial scientists, and national and international collaborations are also planned. Potential beneficiaries of the resulting novel materials and technologies include the chemical, pharmaceutical and biomedical industries, and companies making displays, photonics and optoelectronic devices. Some possible applications are in multi-million dollar industries, such as replacing the molecular liquid crystals in displays with colloidal liquid crystals, and developing new polymer "latex" paints with higher viscosity and better optical properties. Photonic crystals and water-based electrorheological fluids could find application in emerging high technologies. Novel "smart" ion-sensitive or biomolecule-sensitive gels for medical applications could also be fabricated. This will lead to scalable and efficient manufacturing processes at the nanoscale.