Program Director's Recommendation Center for Membrane Applied Science and Technology (MAST) Proposal # 1230142 Zhang
This proposal seeks funding for the Center for Membrane Applied Science and Technology (MAST) at the University of Colorado site. Funding Requests for Fundamental Research are authorized by an NSF approved solicitation, NSF 11-570. The solicitation invites I/UCRCs to submit proposals for support of industry-defined fundamental research.
Membrane technology represents one of the most effective, energy-saving approaches for several separation processes, including ultra-filtration (UF), reverse osmosis (RO), pervaporation (PV), and gas separation. Membrane materials play a pivotal role in determining process effectiveness. Therefore, development of new membrane materials with outstanding separation characteristics is vital to sustain and expand the growth of membrane separation technology. In response to this research opportunity, preparation of a novel class of polymeric membranes integrated with structure-tunable, three dimensional (3-D) well-defined, shape-persistent molecular cages is proposed. These cage-integrated porous membranes are expected to not only significantly enhance the permeability of certain target molecules, but also enable efficiently encoding both dimensional (pore size/distribution) and functional information (guest recognition, sensing, catalysis, etc.) into the final membranes in a modular fashion. The performance of these membranes in separation of CO2/N2, water/alcohol, and olefin/paraffin will be investigated.
The proposed cage-integrated membranes will open completely new directions for fabricating novel defect-free, composite polymeric membranes that can be used for a number of industrially and environmentally important separations, such as CO2/N2, water/ethanol or paraffin/olefin. The proposed work will be a platform for providing new opportunities for outreach, education, and minority involvement on multiple levels. This interdisciplinary research will provide all students, both graduate and undergraduate, exposure to both fields. More than five undergraduate students will be involved in the research plan while special attention will be given to recruit students from minorities and underrepresented groups. The results from the proposed work will be disseminated in professional conferences and journals, via an interactive website, and also integrated into both undergraduate and graduate courses.
In this NSF IIP project, we successfully demonstrated a series of microporous polymer frameworks (PPFs) with novel [3 + 4] structure motif can be constructed through dynamic imine chemistry. The BET surface area of these PPFs is up to 1740 m2 g–1. Owing to the narrow pore size distribution and electron-rich pore surface, PPFs exhibit exceptionally high H2 uptake of up to 2.75 wt % (77 K and 1 bar), C2H2 uptake of 17.9 wt % (273 K and 1 bar), and CO2 uptake of 26.7 wt % (273 K and 1 bar). Moreover, PPFs show a good CO2/N2 adsorption ideal selectivity (up to 20.4/1), as well as CO2/CH4 selectivity (up to 11.0/1), at 273 K and 1 bar. The gas adsorption properties strongly depend on the building block size and functionalities. Introduction of the hydroxyl functional group to the building block design significantly increased the C2H2 uptake of the framework. Collectively, size and functional group dependent characteristics along with the relatively low cost for large-scale manufacturing of these porous polymers open a possibility for tailoring properties and preparing organic porous polymers highly competitive in gas storage and separation applications. Preliminary results on the membrane fabrication and study showed the promise of integrating organic cage molecules into polymer membranes to enhance their permeability and selectivity. We have also shown that porous polymer networks prepared through alkyne metathesis consistently displayed higher specific surface area and higher thermal stability compared to those networks prepared through Sonogashira cross-coupling under similar reaction conditions at various temperatures. Although the networks prepared through alkyne metathesis are amorphous at this stage, it is conceivable that such a dynamic covalent approach could generate ordered materials in the future. Lastly, we also reported a readily accessible silver(I) coordinated phenanthroline-based polymer, which shows high adsorption selectivity of ethylene over ethane at ambient temperature and pressure. Both the polymer structure and the silver(I) complexation account for the high gas uptake and high selectivity in ethylene/ethane adsorption. The PI and his research team on this project gave five invited talks at international and national conferences, eight invited talks at universities, two invited talks at companies, and four contributed poster presentations at a regional or national conference on progress in this cage- and framework-based porous materials project. The PI has mentored one high school student in the lab research; served as a judge at the Regional Science Fair; organized a special symposium on "Design and Applications of Organic and Metal-Organic Porous Materials", 244th ACS National Meeting, Philadelphia, PA, August 2012; and served as Guest Editor for the special issue on "Porous Polymers" that will be published on the Polymers journal in 2014.
