The 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.
