SGER: Spontaneous Formation of Ordered Structures from a Capillary-Held Solution

美国国家科学基金会-化学和运输系统颗粒和多相过程计划(1415年)提案编号：0730611主要研究员：林志群隶属：爱荷华州立大学提案标题：SGER：从毛细管持有的溶液自发形成有序结构智力价值通过固体基质上的液滴不可逆溶剂蒸发非挥发性溶质的动态自组装被广泛认为是一种非光刻方法，可自发形成复杂的大规模结构。然而，蒸发液滴内部的流动不稳定性往往会导致非平衡和不规则的耗散结构，如对流模式、指进不稳定性等。因此，要充分利用蒸发作为一种简单的工具来获得有序的二维结构，就需要对流动不稳定性和蒸发过程进行精细的控制。这项研究的目的是探索一种简单的一步法，以精确可控的方式生产微结构和纳米结构材料，而不需要光刻技术和外部磁场。提出了两个具体目标。首先，通过控制受限几何形状(即毛细管持有的溶液)中含有非挥发性溶质的蒸发液滴的流动，创建具有前所未有的规律性的有序结构。第二，理解耐人寻味结构的形成机制。我们打算用均聚物生产高度规则的结构。这项研究的智力价值体现在创新性研究中，该研究利用受限几何结构作为独特的环境来控制蒸发液滴内的流动，进而以前所未有的规律性一步调节有序结构的形成，用于光学、电子、组织工程和纳米技术。更广泛的影响拟议工作的更广泛影响包括在研究生和本科生层面加强纳米科学教育。暑期纳米材料研究将招募女本科生，从而加强未被充分代表的群体对该项目的参与。在这个项目中产生的知识可能会导致创造光学、微电子和光电子设备，由于聚合物构建块的周期性排列，这些设备显示出新的功能，从而将基本的科学发现转化为有益于社会的技术。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)Proposal Number: 0730611 Principal Investigator: Lin, Zhiqun Affiliation: Iowa State University Proposal Title: SGER: Spontaneous Formation of Ordered Structures from a Capillary-Held solution Intellectual MeritDynamic self-assembly of nonvolatile solutes through irreversible solvent evaporation of a drop from a solid substrate is widely recognized as a nonlithography route for the spontaneous formation of complex, large-scale structures. The flow instabilities within the evaporating droplet, however, often result in nonequilibrium and irregular dissipative structures, e.g., convection patterns, fingering instabilities, and so on. Therefore, to fully utilize evaporation as a simple tool for achieving well-ordered 2D structures, it requires delicate control over flow instabilities and evaporation process. The aim of the proposed research is to explore a simple, one-step method for producing micro- and nanostructured materials in a precisely controllable manner, dispensing with the need for lithography techniques and external fields. Two specific objectives are proposed. First, creating ordered structures with unprecedented regularity by controlling the flow of an evaporating droplet containing nonvolatile solutes in restricted geometries (i.e., a capillary-held solution). Second, understanding the mechanism of the formation of intriguing structures. We intend to produce highly regular structures with homopolymers. The intellectual merit of the proposed research is manifested in the innovative studies of exploiting restricted geometries as unique environments for controlling the flow within an evaporating droplet, which, in turn, regulate the ordered structure formation in one-step with unprecedented regularity for use in optics, electronics, tissue engineering, and nanotechnology. Broader ImpactsThe broader impacts of the proposed work include stronger nanoscience education at the graduate and undergraduate levels. Female undergraduate students will be recruited for summer nanomaterials research, thus strengthening the involvement of an underrepresented groups in the project. Knowledge generated in this project may lead to the creation of optical, microelectronic, and optoelectronic devices that exhibit novel functions due to the periodic arrangement of polymeric building blocks, thus transitioning fundamental scientific discoveries into useful technologies that benefit society.