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Modeling of Hybrid Materials

Modeling of Hybrid Materials. Alessandro Patti Complex Systems Department of Chemical Engineering, URV Tarragona Supervisor: Flor R. Siperstein. Summary. Hybrid materials Monte Carlo simulations Aims of the project and applications Simulation method First results Next steps.

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Modeling of Hybrid Materials

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  1. Modeling of Hybrid Materials Alessandro Patti Complex Systems Department of Chemical Engineering, URV Tarragona Supervisor: Flor R. Siperstein

  2. Summary • Hybrid materials • Monte Carlo simulations • Aims of the project and applications • Simulation method • First results • Next steps Key words: MC simulations, self-assembly, phase diagrams, mesoporous materials Alessandro Patti Modelling of Hybrid Materials

  3. Hydrophobic tail Hydrophilic head Hybrid materials Surfactant Micelle + Inorganic precursor Synthesis mechanisms: 1. LC templating 2. Ion exchange Organic-inorganic structured material Alessandro Patti Modelling of Hybrid Materials

  4. Mesoporous materials Removal of the organic matter: mesoporous matrix Pore size: 2 nm < d < 50 nm Material properties: Optical Mechanical Chemical { • Optics • Electronics • Membranes • Catalysis • Sensors Main applications Alessandro Patti Modelling of Hybrid Materials

  5. Objective Generation of Random Configurations Calculation of macroscopic properties from microscopic properties Use of Random Number Importance Sampling Markov Chain Metropolis Algorithm Approximations Averaging Method Periodic Boundary Condition Minimum Image Convention Neighborhood List Ensemble Averages NVT Ensemble NPT Ensemble mPT Ensemble Monte Carlo Simulations Alessandro Patti Modelling of Hybrid Materials

  6. Monte Carlo Simulations Start Generate initial configuration Random Number Generator Calculate Energy PBC and MIC Loop Ncycles Trial Move Acceptance Criteria Importance Sampling Calculate Summation of Properties End Average Properties Alessandro Patti Modelling of Hybrid Materials

  7. Aims of the project This research project will try to: model and understand at a molecular level the formation and properties of self-assembled hybrid materials determine the phase behavior of ordered mesoporous metal oxides using surfactants as structure directing agents predict the material's final structure and the mechanism for the transformation of spherical micelles into ordered liquid crystals phases determine the equilibrium of the surfactant-inorganic structures, the regions in the phase diagram where they are observed and the stability of different phases Alessandro Patti Modelling of Hybrid Materials

  8. Inorganic component: silica, 2 connected sites in the box Surfactant: H4T4 - 8 connected sites in the lattice box 3D lattice MC simulations in the N,V,T ensemble Coordination number: 26 Effective interaction Simulation method Solvent: water, empty sites Moves: reptation, bias, partial regrowth Alessandro Patti Modelling of Hybrid Materials

  9. Results Partial miscibility L = 24*24*100 T* = 8.0 Nsurf = 1000 Ninorg = 2000 N = 3•109 Alessandro Patti Modelling of Hybrid Materials

  10. Results – Phase diagrams Partial miscibility T* = 8.0 Alessandro Patti Modelling of Hybrid Materials

  11. Conclusions Monte Carlo simulations are used to study the formation and properties of self-assembled hybrid materials A lattice model is used to represent the organic and the inorganic components Phase separation and aggregation properties are studied in terms of equilibrium and stability of the final structures Alessandro Patti Modelling of Hybrid Materials

  12. Its shape and location determine the different liquid crystal phases that can be formed Next steps Immiscibility gap?? Alessandro Patti Modelling of Hybrid Materials

  13. References • Phase Separation and Liquid Crystal Self-Assembly in Surfactant-Inorganic- • Solvent Systems, Flor R. Siperstein and Keith E. Gubbins, Langmuir 2003, 19, 2049- • 2057 • Chemical Strategies To Design Textured Materials: from Microporous and • Mesoporous Oxides to Nanonetworks and Hierarchical Structures, Galo J. de A. • A. Soler-Illia, Clement Sanchez, Benedicte Lebeau and Joel Patarin, Chem. Rev. • 2002, 102, 4093-4138 • Ternary Oil-Water-Amphiphile Systems: Self-Assembly and Phase Equilibria • S.Y. Kim, A. Z. Panagiotopoulos and M. A. Floriano, Molec. Phys., 100, 2213-20, • 2002 Alessandro Patti Modelling of Hybrid Materials

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