CAREER: A Few Layer Thin, Graphene-Based Membranes: Nanostructure Understanding, Permeation Mechanisms and Separation Applications

[1451887]南卡罗莱纳大学哥伦比亚分校。本研究的目标是合理设计几层薄（厚度为3nm）的石墨烯基膜，了解其纳米结构和渗透机制，并研究其对各种混合物进行选择性、高通量分离的潜力。该研究有望对混合物分离产生重大的科学和技术影响，并具有革命性的膜分离技术的巨大潜力。如果成功，这种具有可调材料性能、膜纳米结构和结构缺陷尺寸的新一代超薄膜将广泛应用于高通量混合物分离，包括气体分离、液体混合物分离和纳滤等，从而大大降低分离中的能量成本。预计本研究可作为合理设计具有可调膜性能的超薄石墨烯基膜的模型。此外，对石墨烯基涂层沉积和涂层纳米结构的基本理解和知识可能对光电应用产生潜在影响，例如触摸屏和有机发光二极管（oled），储能和光伏电池。合理设计和优化纳米结构的超薄膜具有实现高效、高通量混合物分离的巨大潜力。提出的研究将集中在制备、纳米结构澄清和几层薄石墨烯基膜的分离研究上。提出的研究目标是i)应用液相沉积工艺来可控地沉积几层薄的石墨烯基膜；Ii)阐明制备膜的纳米结构，并将沉积参数与所得到的纳米结构联系起来；Iii)了解分子通过几层薄膜的渗透机制，研究各种蚀刻工艺对孔径的控制；iv)探索几种薄层石墨烯基膜对各种气体和液体混合物的分离潜力。我们将通过真空过滤、浸涂和铸造蒸发的方法在合适的多孔基板上沉积具有可控性能的氧化石墨烯（GO）薄片；采用宏观和微观技术来表征沉积的薄涂层/膜的纳米结构；通过气体、蒸汽和液体渗透，探索氧化石墨烯和还原氧化石墨烯（rGO）的分子运输途径，包括层间间距和结构缺陷；研究了加压气体渗透、渗透蒸发和液体过滤对混合物的分离。该计划建议通过提高STEM领域所有学生的教育水平，将研究和教育结合起来，特别强调在这一人口中保留少数民族学生。PI利用南加州大学现有的一些项目来提供组织结构，并为各种活动提供资源。具体来说，PI计划(1)在研究领域建立一个专题研究生班，(2)尝试招募一名GEM学者作为博士导师，(3)每年接待2名URM本科生研究人员，(4)参加南加州大学组织的K-12外展活动，并与一所少数民族高中建立持续的关系，其中PI每年将访问4次。

1451887YuUniversity of Sourth Carolina at ColumbiaThe goal of this proposed research is to rationally design few layer thin (thickness 3 nm), graphene-based membranes, understand their nanostructures and permeation mechanisms, and study their potential for selective, high flux separation of a wide range of mixtures. This proposed research is expected to have great scientific as well as technological impact on mixture separations and has great potential to revolutionize separation using membrane technology. If successful, this new generation ultrathin membranes with tunable material properties, membrane nanostructures, and structural defects sizes will have wide applications for high throughput mixture separations, including gas separation, liquid mixture separation, and nanofiltration, etc., and thus greatly reduce energy cost in separations. It is anticipated that this study could serve as a model for the rational design of ultrathin, graphene-based membranes with tunable membrane performance. In addition, the obtained fundamental understanding and knowledge on graphene-based coating deposition and coating nanostructures may have potential impact on optoelectronics applications, such as touch screens and organic light emitting diodes (OLEDs), energy storage, and photovoltaic cells. Ultrathin membranes with rationally designed and optimized nanostructures have great potential to achieve effective mixture separation with high throughput. The proposed research will focus on fabrication, nanostructure clarification, and separation study of a few layer thin, graphene-based membranes. The objectives of the proposed research are i) applying liquid phase deposition processes to controllably deposit a few layer thin, graphene-based membranes; ii) elucidating the nanostructures of fabricated membranes and correlating the deposition parameters with the resulting nanostructures; iii) understanding permeation mechanisms of molecules through the a few layer thin membranes and investigating various etching processes on controlling pore sizes; and iv) exploring the separation potential of a few layer thin, graphene-based membranes for various gas and liquid mixtures. We will deposit graphene oxide (GO) flakes with controlled properties on appropriate porous substrates by vacuum filtration, dip-coating, and casting-evaporation; employ both macroscopic and microscopic techniques to characterize the nanostructures of deposited thin coatings/membranes; explore molecular transport pathways through GO and reduced GO (rGO), including interlayer spacing and structural defects, by gas, vapor and liquid permeation; study the separation of mixtures by pressurized gas permeation, pervaporation and liquid filtration. The PI proposes the integration of research and education through advancement of the education of all students in the STEM fields with special emphasis on enhancing retention of minority students in this population. The PI has leveraged a number of existing programs at USC to provide organizational structure and to resource the various activities. Specifically, the PI plans(1) the development of a special topics graduate class in the study area, (2) try to recruit a GEM scholar as a PhD mentee, (3) host 2 URM undergraduate researchers per year, (4) participate in K-12 outreach organized by USC and develop a continuous relationship with one minority serving high school that will include 4 visits from the PI each year.