In-situ Monitoring and Active Controls of Individual Nucleation and Crystal Growth through Nanoscale Mass Transport

本项目由美国国家科学基金化学分部化学测量与成像项目资助。佐治亚州立大学的王刚利教授和他的团队成员开发了新的分析方法，以更高的时间和空间分辨率提供了早期成核和随后晶体生长的知识。高质量的单晶具有良好的化学、物理和机械性能，在化工、制药和材料等行业的实际应用中具有优异的性能。缺乏有效的方法来测量和主动控制结晶过程已经限制了基础研究和实际应用的进展。原位测量动态过程从而主动控制晶体形成的能力有望建立急需的高通量和高效率结晶技术。更广泛的影响表明，提出的目标是推进结晶的范式。来自亚特兰大大都会弱势群体和背景不利的学生通过赠款活动获得第一手知识和经验。本提案的总体目标是建立一种结合光学成像的电分析方法，能够对单核形成和单晶生长进行现场监测和主动控制。分析平台正在开发优化的纳米结构和表面功能，以在空间上限制单个细胞核在最早阶段（分子组装）的形成和生长。单晶核形成和生长的动力学，由目标分子在核周围的局部运输所控制，通过编程电位波形外部控制。主动控制质量输运是传统结晶方法中采用的被动扩散机制的另一个优点。由于传输和组装过程与离子电流信号以及光学性质的变化有关，因此可以进行现场监测和调整，以定制单个事件的成核和生长动力学。

This project is funded by the Chemical Measurement and Imaging program of Chemistry Division at the National Science Foundation. Professor Gangli Wang and his group members at Georgia State University develop new analytical methods providing knowledge of early-stage nucleation and subsequent crystal growth at greater time and spatial resolutions than is otherwise possible. High quality single crystals display chemical, physical, and mechanical properties, and have superb performance in practical applications in chemical, pharmaceutical and materials industries. Lack of capable methods to measure and to actively control the crystallization process has been a limit on the advance of fundamental research as well as practical applications. The capability to measure the dynamic process in-situ and thus to actively control crystal formation is expected to establish much-needed high throughput and high efficiency crystallization technology. The broader impacts are demonstrated in that the proposed aims advance the paradigm of crystallization. Students from underrepresented groups and from disadvantageous backgrounds in metro Atlanta gain first-hand knowledge and experiences through the grant activities. The overarching goal of this proposal is to establish an electroanalytical methodology combined with optical imaging that enables in-situ monitoring and active controls of single nucleus formation and single crystal growth. Analytical platforms are being developed with optimized nanostructures and surface functionalities to spatially confine the formation and growth of a single nucleus at the earliest stage (molecular assembly) one at a time. The kinetics of a single crystal nucleus formation and growth, governed by local transport of the target molecules around the nucleus, are controlled externally via a programmed potential waveform. Active control of mass transport is another superior advantage over the passive diffusion mechanism adopted in conventional crystallization methods. Because the transport and assembly processes are associated with changes in ionic current signals as well as optical properties, in-situ monitoring and adjustments are performed to tailor the nucleation and growth kinetics of individual events.