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

这项研究的目标是合理地设计几层薄(厚度3 nm)的石墨烯基膜，了解它们的纳米结构和渗透机制，并研究它们对各种混合物进行选择性高通量分离的潜力。这项研究有望对混合物分离产生重大的科学和技术影响，并具有革新膜分离技术的巨大潜力。如果成功，这种材料性质、膜纳米结构和结构缺陷尺寸可调的新一代超薄膜将在包括气体分离、液体混合物分离和纳滤等在内的高通量混合物分离中得到广泛应用，从而大大降低分离的能源成本。本研究可望为合理设计具有可调膜性能的超薄石墨烯基膜提供参考。此外，在基于石墨烯的涂层沉积和涂层纳米结构方面获得的基础知识可能会对光电应用产生潜在的影响，如触摸屏和有机发光二极管(OLED)、能量存储和光伏电池。合理设计和优化纳米结构的超薄膜具有实现高效、高通量分离混合物的巨大潜力。拟开展的研究将集中在几层石墨烯薄膜的制备、纳米结构的澄清和分离研究上。拟议研究的目标是：i)应用液相沉积工艺可控地沉积几层基于石墨烯的薄膜；ii)阐明所制备的膜的纳米结构并将沉积参数与所得到的纳米结构相关联；iii)了解分子通过几层薄膜的渗透机制并研究各种控制孔径的刻蚀工艺；以及iv)探索几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、浸渍涂层和浇铸蒸发在适当的多孔衬底上沉积性能可控的氧化石墨烯(GO)薄片；利用宏观和微观技术表征沉积的薄膜/膜的纳米结构；探索通过GO和还原GO(RGO)通过气体、蒸汽和液体渗透的分子传输途径，包括层间距和结构缺陷；研究加压气体渗透、渗透汽化和液体过滤分离混合物。国际学生联合会建议通过促进STEM领域的所有学生的教育，将研究和教育结合起来，特别强调加强少数民族学生在这一群体中的留存。PI利用了南加州大学的一些现有计划来提供组织结构并为各种活动提供资源。具体地说，国际扶轮计划(1)在研究区域发展一个专题研究生班，(2)尝试招募一名宝石学者作为博士导师，(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，并与一所少数族裔服务的高中发展持续的关系，其中包括国际扶轮每年访问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.