Experimental and Theoretical Investigations of Electrostatic Interactions and Ordering in Highly Charged Colloidal Assemblies

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”化学系的分析和表面化学（ASC）项目支持匹兹堡大学的Sanford A. Asher教授和Rob Coalson教授的研究项目。Asher教授的小组正在进行实验研究，而Coalson小组正在从理论上研究静电相互作用如何决定形成光子晶体材料的晶体胶体阵列（CCA）的自组装和结构顺序。该项目将研究高电荷、单分散胶体粒子的高浓度、低盐悬浮液中静电相互作用的性质。该项目的实验部分旨在揭示基本静电相互作用的形式，通过使用胶体探针原子力显微镜对集中的、高电荷的胶体粒子分散体进行静电相互作用的直接测量。本工作通过监测CCA的光衍射，研究了电荷诱导这些粒子自组装成fcc CCA阵列。这些实验结果将通过模拟高浓度、高电荷粒子分散的胶体粒子相互作用的理论计算来合理化。这个项目将导致对强相互作用胶体和大分子中的静电相互作用的基本理解。这些相互作用在生物和材料系统中无处不在。此外，加深理解将推动纳米科学和纳米技术的进步，特别是在通过电荷诱导自组装自下而上制造光子晶体材料方面。参与该项目的研究生和博士后研究人员将被培养成为学术科学、政府研究实验室和工业领域的创新研究人员和领导者。通过这个研究项目，Asher教授和Coalson教授将为本科生提供研究培训，并为大匹兹堡社区的各级学生提供丰富的机会。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." The Analytical and Surface Chemistry (ASC) program of the Division of Chemistry supports the research program of Professor Sanford A. Asher and Professor Rob Coalson of the University of Pittsburgh. Prof. Asher's group is experimentally investigating and the Coalson group is theoretically investigating how electrostatic interactions determine the self assembly and structural ordering of Crystalline Colloidal Arrays (CCA) which form photonic crystal materials. The project will investigate the nature of electrostatic interactions in highly concentrated, low salt suspensions of highly charged, monodisperse colloidal particles. The experimental part of the project aims at unveiling the form of the fundamental electrostatic interactions by direct measurements of electrostatic interactions using Colloidal Probe Atomic Force Microscopy on concentrated, highly charged colloidal particle dispersions. This work examines the charge induced self-assembly of these particles into an fcc CCA array by monitoring light diffraction from the CCA. These experimental results will be rationalized by theoretical calculations that model colloidal particle interactions in high concentration, highly charged particle dispersions. This project will lead to a fundamental understanding of electrostatic interactions in strongly interacting colloids and macromolecules. These interactions are ubiquitous in biological and material systems. Moreover, an increased understanding will enable advances in nanoscience and nanotechnology, especially in the bottom-up fabrication of photonic crystal materials through charge induced self-assembly. The graduate students and postdoctoral researchers who work on this project will be trained to become innovative researchers and leaders in academic science, government research laboratories and in industry. Through this research project, Prof. Asher and Prof. Coalson will provide research training for undergraduate students as well as enrichment opportunities for students of all levels in the greater Pittsburgh community.