GOALI: Molecular Modeling of Confined Nano-Phases and Novel Nano-Porous Materials

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Project AbstractGOALI: Molecular Modeling of Confined Nano-Phases and Novel Nano-Porous Materials (CTS-0626031)Keith Gubbins, North Carolina State Univ.; Matthias Thommes, Quantachrome, Instruments, Inc.This is a GOALI project involving university-industry collaboration between researchers at North Carolina State University (NCSU) and at Quantachrome Instruments, a leading maker of instruments for characterizing nano-structured materials. The aim of this project is to develop and apply atomistic simulation methods to obtain realistic atomic models of several new classes of synthetic nanoporous materials, and to use these to investigate confined phases within these materials and to assist in optimization of the materials for specific applications. The materials to be studied are templated mesoporous silicas, and the recently reported mesoporous carbons (CMKs), carbide-derived carbons and periodic mesoporous organosilicas (PMOs). These materials hold great promise for applications in microelectronics (mesoporous silicas), as electrodes in fuel cells, batteries and supercapacitors (mesoporous carbons, carbide-derived carbons), hydrogen storage (carbide-derived carbons), as catalytic and chromatographic supports (organosilicas), as sensors and in environmental remediation (organosilicas). Accurate and realistic atomic models of these materials are essential to the development of optimal material designs for these applications. Preparation of these materials and experimental studies of adsorption on them will be performed by researchers at Quantachrome Instruments, and this data will be provided to the NCSU researchers. Quantachrome scientists will also offer advice on directions for the modeling work carried out at NCSU. The NCSU researchers have already developed realistic models of templated mesoporous silica materials, which form the starting point in the synthesis of mesoporous carbons, and will develop Monte Carlo (MC) simulation methods that mimic the synthesis of these carbons within the silica, followed by silica removal and relaxation. Both lattice and off-lattice MC methods will be developed to model the organosilicas. MC and molecular dynamics simulations will be carried out to study adsorption and diffusion in these materials.Intellectual Merit. Because these novel materials are not crystalline, a combination of atomistic simulation and experiment provides the best route to developing realistic atomic models of them. Existing models of such materials assume over-simplified pore geometries (slit or cylinder shaped) and are inadequate for predicting the behavior of adsorbed phases. The realistic models that are being developed will make possible fundamental investigations of the influence of confinement and nature of the material on adsorption, phase changes, reactions and diffusion. PMOs offer the possibility to tune the chemistry of the pore walls to obtain a range of interactions from hydrophilic to hydrophobic, while the CMKs combine desirable features of carbons (conductivity, mechanical and thermal stability) with those of silicas (large pores, regular pore structure).Broader Impact. Improved understanding of the behavior of nano-phases confined within these novel nano-porous materials will impact a broad range of technologies, and is essential to the design of new biological and chemical sensors, nano-reactors, hydrogen storage media, electrodes for fuel cells and batteries, and nano-structured catalysts. Graduate and undergraduate students working on this project will learn modern multi-scale modeling methods, and will gain experience of international cooperative research through our active collaborations in this area with researchers in France, Germany, Poland, China and Hong Kong. Graduate students from under-represented groups will be recruited from colleges and universities in North Carolina with whom NCSU has established ties and programs.