Conformation and Alignment Control in Scalable Graphene Film Processing

该项目的重点是在液相加工过程中石墨烯动力学的表征和控制。石墨烯具有出色的机械、热和电气性能，具有广泛的电子和航空航天应用。然而，构象（内部构型）和排列（取向）对石墨烯基薄膜的实际性质具有强烈的影响。该项目将模拟与薄膜加工过程中石墨烯动力学的实验研究相结合。采用了两种方法：（1）利用布朗动力学/粒子跟踪模拟来模拟各种膜处理流程期间的石墨烯构象。该技术在预先计算的动态流场中模拟石墨烯构象作为空间和时间的函数。(2)实验上利用相同的流来生产导电石墨烯基薄膜和石墨烯/聚合物复合膜。加工流类型和强度的影响被量化的宏观膜性能和纳米级石墨烯的构象和排列。石墨烯构象被量化为稳定剂类型和超声能量的函数。如果成功，这些新的模拟和实验将填补工程界的关键需求，为溶液中石墨烯形态的预测、表征和控制提供基础科学见解。模拟和实验确定了加工参数空间，其中流动力促进了给定应用所需的微观结构和性能;例如，拉伸流动力可以促进薄膜中的透明性和导电性的平坦、对齐的石墨烯构象。这项工作对工业加工技术具有广泛的影响，包括（1）用于电子产品的透明导电薄膜的喷墨印刷和卷对卷涂布，以及（2）用于增强和传感的多功能纳米复合材料涂层。 这些研究任务将与研究生和本科生教育相结合，重点是课程开发和独立的本科生研究培训，以及为本科生和K-12学生开展的外联活动。

This project focuses on the characterization and control of graphene dynamics during liquid-phase processing. Graphene has outstanding mechanical, thermal, and electrical properties with a wide range of electronic and aerospace applications. However, conformation (internal configuration) and alignment (orientation) have a strong influence on the practical properties of graphene-based films. This project combines simulations with experimental studies of graphene dynamics during film processing. Two approaches are utilized: (1) Brownian Dynamics/Particle Tracking simulations are utilized to model graphene conformation during various film processing flows. This technique simulates graphene conformation as a function of space and time in a pre-computed dynamic flow field. (2) The same flows are experimentally utilized to produce conductive graphene-based thin films and graphene/polymer composite films. The effects of processing flow type and strength are quantified on both macroscopic film properties and nanoscale graphene conformation and alignment. Graphene conformation is quantified as a function of stabilizer type and sonication energy. If successful, these novel simulations and experiments will fill a critical need in the engineering community to provide fundamental scientific insight into the prediction, characterization, and control of graphene morphology in solution. The simulations and experiments identify the processing parameter space where flow forces promote the desired microstructure and properties for a given application; for instance, extensional flow forces can promote a flat, aligned graphene conformation for transparency and conductivity in thin films. This work has broad impacts for industrial processing techniques including (1) inkjet printing and roll-to-roll coating of transparent, conductive, thin films for use in electronics and (2) multifunctional nanocomposite coatings for reinforcement and sensing. These research tasks will be integrated with graduate and undergraduate education, with a heavy emphasis on curriculum development and independent undergraduate research training, in addition to outreach activities for undergraduates and K-12 students.