Collaborative Research: Dual-droplet Electrohydrodynamic Printing of 2D Nanosheets

合作研究：二维纳米片的双液滴电流体动力打印

基本信息

批准号：
1635729
负责人：
Tse Nga Ng
金额：
$ 5万
依托单位：
University of California-San Diego
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-10-01 至 2018-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635729&HistoricalAwards=false
关键词：
Collaborative Research Dual droplet Electrohydrodynamic

项目摘要

Atomically thin, 2D nanosheets are promising components for next-generation electronics. However, there is a lack of scalable manufacturing processes to fully showcase the superior properties of nanosheet materials. Specifically, no currently available technique has the requisite placement accuracy and topology control to build aligned stacks of unwrinkled nanosheets. This award supports fundamental research on a novel dual-droplet electrohydrodynamic printing process. Research results can enable the development of a unique additive manufacturing platform for patterning nanosheets, as well as other anisotropic colloidal particles (e.g., nanowires, and quantum dots). Such technology is crucial for US to stay competitive in manufacturing and bring forth novel applications of nanosheets in high-performance printed electronics, sensors, actuators, and energy devices. The new dual-droplet electrohydrodynamic printing process involves first depositing a support droplet which acts as a Langmuir-Blodgett trough, followed by a wetting droplet containing colloidal 2D nanosheets. Assembly of the 2D nanosheets will occur as the support droplet evaporates. The research objectives are (1) to understand the effects of solvent surface tensionand volume ratio of the support and wetting droplets on the spreading of the wetting droplet over the support droplet; (2) to understand the effects of nanosheet size and concentration, and substrate wetting properties on the alignment of nanosheets; and (3) to establish the structure-property relationships of the deposited nanosheets. Graphene and Molybdenum disulfide nanosheets will be used in this study. To achieve the first objective, the dual-droplet printing experiments will be conducted. Solvent surface tension will be varied between 30-50 mN/m by changing solvent composition, and volume ratio will be varied from 1 to 100 by changing the driving voltage and pulse width for both support and wetting droplets. The temporal change of spreading area will be measured by high-speed photography with a few tens of microseconds resolution. The second objective will be achieved by both experimental study and computer simulation. For dual-droplet printing experiments, nanosheet size will be varied between 0.2-10 µm in mean diameter, nanosheet concentration in the wetting droplet between 0.01-1 mg/mL, and the receding contact angle of the support droplet will be varied from about 0° with a pinned contact line up to ~90° with a depinned contact line. The nanosheet alignment in the assembly will be analyzed by microscopy characterization. A model of Lagrangian particle tracking will be created for prediction of nanosheet alignment, where molecular dynamics simulation will compute nanosheet dynamics under the evaporation-induced flow. Simulation predictions will be verified by experimental results in terms of nanosheet orientation and alignment. To achieve the third objective, the structure (in terms of topological roughness, sheet-to-sheet alignment, gaps or overlaps between nanosheets) of the deposited nanosheet assembly will be measured using electron microscopy and atomic force microscopy, and the property (conductivity) will be measured using four-point probe.

原子上的薄，2D纳米片是下一代电子产品的组件。但是，缺乏可扩展的制造工艺来充分展示纳米片材料的出色特性。具体而言，目前没有技术具有必要的放置准确性和拓扑控制来构建一堆无忧的纳米片。该奖项支持有关新型双滴滴电水动力印刷过程的基本研究。研究结果可以使开发一个独特的添加剂制造平台，用于构图纳米片以及其他各向异性胶体颗粒（例如纳米线和量子点）。对于我们来说，这种技术在制造业中保持竞争力至关重要，并在高性能印刷的电子，传感器，执行器和能源设备中提出纳米片的新颖应用。新型的双抽水电水动力印刷过程涉及首先沉积的液滴，该液滴充当Langmuir-Blodgett槽，然后是含有Coloidal 2d纳米片的润湿液滴。当支撑液滴蒸发时，将发生2D纳米片的组装。研究目标是（1）了解溶液表面张力和支撑液滴的体积比对润湿液滴在支撑液滴上的扩散的影响；（2）了解纳米片的大小和浓度以及底物润湿特性对纳米片对齐的影响；（3）建立沉积纳米片的结构特性关系。在这项研究中，将使用石墨烯和钼纳米片。为了实现第一个目标，将进行双浪漫打印实验。通过更改溶剂的组成，溶剂表面张力将在30-50 mn/m之间变化，并且通过更改支撑液和润湿液滴的驾驶电压和脉冲宽度，体积比将从1到100变化。扩散区域的暂时变化将通过高速摄影，并以几十微秒的分辨率来衡量。第二个目标将通过实验研究和计算机模拟来实现。对于双抽动打印实验，纳米片的尺寸将在平均直径0.2-10 µm之间变化，润湿液滴的纳米片浓度在0.01-1-1 mg/mL之间，支撑液滴的退缩接触角将与约90°接触的固定接触量大约0°而变化。组件中的纳米片对齐将通过显微镜表征分析。将创建一个Lagrangian粒子跟踪的模型，以预测纳米片对齐，其中分子动力学模拟将在经济引起的流动下计算纳米片动力学。模拟预测将通过实验结果来验证纳米片的方向和比对。为了实现第三个目标，将使用电子显微镜和原子力显微镜测量沉积纳米片组件的结构（就拓扑粗糙度，板间比对，纳米片之间的间隙或重叠），并使用四点探测测量特性（电导率）。