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Science in China Series B: Chemistry

, Volume 50, Issue 3, pp 318–326 | Cite as

Preparation and photochromism of Keggin-type molybdphosphoric acid/silica mesoporous composite thin films

  • Zhang XueAo 
  • Wu WenJian 
  • Man YaHui 
  • Tian Tian 
  • Tian XiaoZhou 
  • Wang JianFang 
Article

Abstract

Using tetraethoxysilane and 3-aminopropyltriethoxysilane as the silica sources, amino-functionalized organic/inorganic hybrid mesoporous silica thin films with 2-dimensional hexagonal structure have been synthesized by evaporation induced self-assembly process in the presence of cetyltrimethyl ammonium bromide templates under acid conditions. The Keggin-type molybdphosphoric acid (PMo) is incorporated into the mesoporous silica thin films with amino-groups by wetness impregnation, and the PMo/silica mesoporous composite thin films are obtained. The results of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and Fourier transform infrared (FTIR) spectra indicate the PMo molecules maintain Keggin structure and are homogeneously distributed inside mesopores. The composite thin films possess excellent reversible photochromic properties, and change from colorless to blue under ultraviolet irradiation. The photochromic mechanism of the composite thin films is studied by ultraviolet-visible (UV-vis), electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS) spectra. It is shown that intervalence charge transfer (IVCT) and ligand-to-metal charge transfer (LMCT) are the main reasons of photochromism. PMo anions interact strongly with amino-groups of the mesoporous suface via hydrogen bond and electrostatic force. After ultraviolet irradiation, the charge transfer occurs by reduction of heteropolyanions accompanying the formation of heteropolyblues with multivalence Mo(VI, V), and the bleaching process of composite thin films is closely related to the presence of oxygen.

Keywords

molybdphosphoric acid silica mesoporous composite thin films preparation photochromism 

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References

  1. 1.
    Kresge C T, Leonowicz M E, Roth W J, Vartuli J C, Beck J S. Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism. Nature, 1992, 359: 710–712CrossRefGoogle Scholar
  2. 2.
    Han C K, Jung S B, Park H H. Effects of traethoxysilane vapor treatment on the cetyltrimethylammonium bromide-templated silica mesoporous low-k film with 3D close-packed array of spherical pores. Appl Surf Sci, 2004, 237: 405–410Google Scholar
  3. 3.
    Zhao D, Yang P, Melosh N, Feng J, Chmelka B F, Stucky G D. Continuous mesoporous silica films with highly ordered large pore structures. Adv Mater, 1998, 10(16): 1380–1385CrossRefGoogle Scholar
  4. 4.
    Aksay I A, Trau M, Manne S, Honma I, Yao N, Zhou L, Fenter P, Eisenberger P M, Gruner S M. Biomimetic pathways for assembling inorganic thin films. Science, 1996, 273: 892–898CrossRefGoogle Scholar
  5. 5.
    Zhang X A, Wu W J, Liu C L, Wang J F. Biomimetic synthesis of ordered mesoporous silica inorganic films at the air-solution interface. Chin J Inorg Chem (in Chinese), 2006, 22(4): 719–723Google Scholar
  6. 6.
    Lu Y, Ganguli R, Drewien C A, Anderson M T, Brinker C J, Gong W, Guo Y, Soyez H, Dunn B, Huang M H, Zink J I. Continuous formation of supported cubic hexagonal mesoporous films by sol-gel dip-coating. Nature, 1997, 389: 364–368CrossRefGoogle Scholar
  7. 7.
    Brinker C J, Lu Y, Sellinger A, Fan H. Evaporationinduced self-assembly: nanostructures made easy. Adv Mater, 1999, 11(7): 579–595CrossRefGoogle Scholar
  8. 8.
    Besson S, Gacoin T, Ricolleau C, Jacquiod C, Boilot J P. Phase diagram for mesoporous CTAB-silica films prepared under dynamic conditions. J Mater Chem, 2003, 13: 404–409CrossRefGoogle Scholar
  9. 9.
    Ogwaw M, Kuroda K, Mori J. Aluminum-containing mesoporous silica films as nano-vessels for organic photochemical reactions. Chem Comm, 2000, 2441–2442Google Scholar
  10. 10.
    Schomburg C, Wark M, Rohlfing Y, Schulz-Ekloff G, Wöhrle D. Photochromism of spiropyran in molecular sieve voids: effects of host-guest interaction on isomer status, switching stability and reversibility. J Mater Chem, 2001, 11: 2014–2021CrossRefGoogle Scholar
  11. 11.
    Bae J Y, Jung J I, Bac B S. Photochromism in spiropyran impregnated fluorinated mesoporous organosiliccate films. J Mater Res, 2004, 19(8): 2503–2509CrossRefGoogle Scholar
  12. 12.
    Okada H, Nakajima N, Tanaka T, Iwamoto M. Improvement in photocyclization efficiency of diaryl ethenes by adjusting the pore size of mesoporous silica. Angew Chem Int Ed, 2005, 44: 7233–7236CrossRefGoogle Scholar
  13. 13.
    Yamase T. Polyoxometalates for molecular devices: Antitumor activity and luminescence. Mol Eng, 1993, 3: 241–262CrossRefGoogle Scholar
  14. 14.
    Hill C L, Bouchard D A. Catalytic photochemical dephydrogenation of organic substrate and polyoxometalates. J Am Chem Soc, 1988, 110: 5471–5476CrossRefGoogle Scholar
  15. 15.
    Zhang T R, Feng W, Bao C Y, Lu R, Zhang X T, Li T J, Zhao Y Y. Fabrication of heteropolyoxometalate-based photochromic inorganic-organic nanocompo sites. J Mater Res, 2001, 16(8): 2256–2263CrossRefGoogle Scholar
  16. 16.
    Pope M T. Heteropoly and Isopoly Oxometalates. Belin: Springer, 1983: 109–112Google Scholar
  17. 17.
    Fleisch T H, Mains G J. An XPS study of the UV reduction and photochromism of MoO3 and WO3. J Chem Phys, 1982, 76(2): 780–786CrossRefGoogle Scholar

Copyright information

© Science in China Press 2007

Authors and Affiliations

  • Zhang XueAo 
    • 1
  • Wu WenJian 
    • 1
  • Man YaHui 
    • 1
  • Tian Tian 
    • 1
  • Tian XiaoZhou 
    • 1
  • Wang JianFang 
    • 1
  1. 1.College of Aerospace and Material EngineeringNational University of Defense TechnologyChangshaChina

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