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Confining Liquid Crystals to Nanoporous Molecular Sieves by Ligia Frunza NIMP, Bucharest - Magurele Bucharest

National Institute of Materials Physics Bucharest-Magurele Romania. Confining Liquid Crystals to Nanoporous Molecular Sieves by Ligia Frunza NIMP, Bucharest - Magurele Bucharest, January 27 2004. L. Frunza. Outline. Introduction confining effects

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Confining Liquid Crystals to Nanoporous Molecular Sieves by Ligia Frunza NIMP, Bucharest - Magurele Bucharest

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  1. National Institute of Materials Physics Bucharest-Magurele Romania Confining Liquid Crystals to Nanoporous Molecular Sieves by Ligia Frunza NIMP, Bucharest- Magurele Bucharest, January 27 2004 L. Frunza

  2. Outline • Introduction • confining effects • aim of the investigations • Experimental • materials (molecular sieves & confining organics) • methods of investigation • Results : dielectric spectroscopy • DSC, DTA, TG • FTIR • optical microscopy/CCV • Co-operations: bilateral • FP6 • resources to collaborate L. Frunza

  3. Source of confining effects: Changes of confined material: size restriction polydispersity connectivity confining topology + surface effects physical properties chemical properties • Introduction Confining effects L. Frunza

  4. Introduction • Aim of the investigations • Molecular sieves Nanoporous materials offering arrays of pores and cavities with known geometry Substitution in their framework may lead to a variety of guest- host interactions New structures are continuously synthesized • Confined matter: liquid crystals • different other organics • Studies aimed to investigate influence of the confinement on phase transitions (LC behavior) thermal stabilization anchoring mode of the molecules at the surface of the molecular sieves location of the organic molecules in the loaded samples inside the pores and/or cavities on the outer surface of the grains / agglomerates • Potential applications of composites based on molecular sieves • microlasers, sensors, biology (by functionalization), catalysts… L. Frunza

  5. Experimental • Molecular sieves. AlMCM-41, AlSBA-15, SiNMS-F Synthesis: NIMP(INCDFM) partners L. Frunza

  6. Experimental • Confined matter L. Frunza

  7. Experimental • Investigation methods • IR & UV-vis spectroscopy in situ • Broadband dielectric spectroscopy (partners) • Thermal analysis (partners) differential thermal analysis (DTA) differential scanning calorimetry (DSC) Optical microscopy /CCV camera Luminescence / thermoluminescence Others thermogravimetry (partners) X-ray diffraction electron microscopy nitrogen absorption meas. (partners) L. Frunza

  8. Results • Confinement of liquid crystals Bulk 8CB A.Schoenhals, H.-L.Zubowa, R.Fricke, S.Frunza, L.Frunza, R.Moldovan, Cryst. Res. Technol. 34, 1309 (1999) L. Frunza

  9. Results • Confinement of liquid crystals Empty molecular sieves L. Frunza, S. Frunza, A. Schönhals, et al., J. Non-cryst. Solids, 307-310 (2002) 503. L. Frunza, H. Kosslick, A. Schönhals, et al. , Proceedings SPIE-4799 (2002) 230. L. Frunza, S. Frunza, A. Schönhals, et al., Stud. Surf. Sci. Catal. 142 (2002) 1323.   L. Frunza, H. Kosslick, S. Frunza, et al J. Phys. Chem B. 106 (2002) 9191. L. Frunza

  10. 1 2 3 1) Bulk 8CB 2) 8CB(A)/AlMCM-41 3) 8CB(B)/AlMCM-41 T = 360 K • Results • Confinement of liquid crystals Loaded molecular sieves • Two relaxation processes may appear. • The slow relaxation process is a new one, due to surface layer. Its temperature dependence follows a VFT law. S.Frunza, A.Schönhals, L.Frunza, et al., Chem.Phys. Lett.307 (1999) 167. S. Frunza,L. Frunza, A. Schönhals, J. Phys. IV France, 10 (2000) , Pr7-115. S. Frunza, L. Frunza, M. Tintaru, et al., Liq. Cryst. Accepted Jan. 2004 L. Frunza

  11. DTA curves: several endothermal and exothermal processes (oxidation/decomposition) • DTA curve do not have the same shape as the corresponding DTG curve • thermal process involving surface species • Results • Thermal analysis L. Frunza

  12. Results • DSC • Partially filled samples with low filling degree do not show phase transitions • Completely filled samples: • A part of confined 8CB shows phase transitions • Downward shift of te peak temperature • C-SA phase transition has the biggest shift • correlation between the depression of the crystallization temperature and the reciprocal diameter of the pores cannot be established • Most of the confined 8CB does not show any phase transitions S. Frunza,L. Frunza, A. Schönhals, et al., Europhys. Lett. 56 (2001) 801.   L. Frunza, S. Frunza, A. Schönhals, et al., Stud. Surf. Sci. Catal. 142 (2002) 1323.   S. Frunza, H. Kosslick, A. Schönhals, et al., J. Noncryst. Solids 325 (2003) 103. L. Frunza

  13. 8CB/AlSBA-15 • Results • In situ FTIR spectroscopy CN vibration is described as a vibration of a localized group Species: Bulk-like LC (2226 cm-1) Randomized state (ca. 2230 m-1) Hydrogen bonded (2241 cm 1) L. Frunza, S. Frunza, A. Schönhals, et al., J.Molec. Struct. 563-564, 491-495 (2001). L. Frunza, H. Kosslick , U. Bentrup, et al., J. Molec. Str. 651-653 (2003) 341-347. L. Frunza,S. Frunza, I. Enache, et al., Mol. Cryst. Liq. Cryst. Accepted September 2003. L. Frunza

  14. J/AlMCM-41 Water amount drcreases by increasing temperature. Jacobsen complex anchoring to the surface is an activated process. L. Frunza • Results • Confinement of Jacobsen complex L. Frunza, H. Kosslick , H. Landmesser, et al., J.Mol.Catal.123, 179-187 (1997) L. Frunza, I. Enache, I. Nicolaie, et al., BPU-5, Serbia, August 2003. L. Frunza, I. Nicolaie, S. Frunza, et al., ICC, Paris, France , July 2004.

  15. L. Frunza • Results • Lyotropic liquid crystals Confinement is constructed during synthesis of nanopores Some results on studies concerning lyotropic micelles are given in a Poster of T. Beica, R. Moldovan, M. Tintaru I. Zgura, S. Frunza T. Beica, R. Moldovan, M.R. Puica, S. Frunza, Liq. Cryst. 29 (2002) 1275. T. Beica, R. Moldovan, Irina Zgura, et al., BPU5, August 25-29, 2003, Serbia T. Beica, R. Moldovan, M. Tintaru,et al., Liq. Cryst. Accepted Dec. 2003

  16. Co-operations Bilateral scientific agreements: Germany, Berlin ACA Hendrik Kosslick Rolf Fricke Ursula Bentrup Irene Pitsch H.-L. Zubowa BAM Andreas Schoenhals COORDINATION ACTION “CONCORDE - Co-ordination of Nanostructured Catalytic Oxides Research and Development in Europe” Framework Programme FP6 Priority 3 Nanotechnology and nanosciences, knowledge-based multifunctional materials, new production processes and devices L. Frunza

  17. Acknowledgements Team of Liquid Crystals and Surface Interactions (NIMP): Stefan Frunza Ligia Frunza Traian Beica Mihaela Tintaru Irina Zgura Irina Nicolaie Rodica Moldovan Organizers of the National Seminar of Nanoscience and Nanotechnology Bucharest 2004 L. Frunza

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