Micro/nano-structural properties of imprinted macroporous titania and zirconia

Some factors affecting micro-/nano-structural parameters of imprinted titania and zirconia have been analysed. Latex particles with different compositions were selected to be used as templates in order to investigate the effect of template–inorganic precursor interaction on the microstructural properties of the oxides. Titanium isopropoxide or zirconium n-propoxide diluted in n-propanol or hexane were used as precursors of titania and zirconia respectively. Samples have been prepared with different alkoxide/solvent ratios and in some cases hydrochloric acid was employed as catalyst. The chemical composition of the template can affect the wall structure, wall thickness and structural contraction. A large crystal wall structure is observed in titania imprinted on poly[styrene-co-(2-hydroxyethylmethacrylate)] and poly[styrene-co-acrylic acid], but when imprinted on polystyrene, a fibre-like wall structure, thinner pore wall and lower structural contraction, are obtained. Chemical interaction between the latex particles and the metal alkoxide seem to be less important for zirconium n-propoxide than for titanium isopropoxide. Therefore, zirconia imprinted on polystyrene, poly[styrene-co-(2-hydroxyethylmethacrylate)] and poly[styrene-co-acrylic acid] shows a similar fibre-like wall structure. Pore walls made of small and homogeneous crystallites have been observed in zirconia obtained using hexane as solvent, probably due to the stability of alkoxy bridges that leads to a low hydrolysis rate. Small crystals building a thin and continuous pore wall are also formed when hydrochloric acid is added to the precursor solution and the hydrolysis takes place in ambient conditions. These microstructural features can be understood as due to both the easy protonation and the hindered condensation process under the experimental conditions used.

[1]  F. Caruso,et al.  Synthesis of macroporous titania and inorganic composite materials from coated colloidal spheres - A novel route to tune pore morphology. , 2001 .

[2]  Bénédicte Lebeau,et al.  Chemical strategies to design textured materials: from microporous and mesoporous oxides to nanonetworks and hierarchical structures. , 2002, Chemical reviews.

[3]  Younan Xia,et al.  Preparation of Mesoscale Hollow Spheres of TiO2 and SnO2 by Templating Against Crystalline Arrays of Polystyrene Beads , 2000 .

[4]  A. Stein,et al.  Synthesis of macroporous minerals with highly ordered three-dimensional arrays of spheroidal voids , 1998, Science.

[5]  F. Caruso,et al.  Lithium Niobate Inverse Opals Prepared by Templating Colloidal Crystals of Polyelectrolyte‐Coated Spheres , 2003 .

[6]  Y. Teraoka,et al.  Preparation of a TiO2 Nanoparticulate Film Using a Two-Dimensional Sol−Gel Process , 1997 .

[7]  Andreas Stein,et al.  Synthesis of highly ordered, three-dimensional, macroporous structures of amorphous or crystalline inorganic oxides, phosphates, and hybrid composites , 1999 .

[8]  A. Stein.  Sphere templating methods for periodic porous solids , 2001 .

[9]  M. Martinelli,et al.  Titania inverse opals for infrared optical applications , 2001 .

[10]  E. Enciso,et al.  Macroporous silica and titania obtained using poly[styrene-co-(2-hydroxyethyl methacrylate)] as template , 2002 .

[11]  Qu,et al.  Brownian Dynamics Simulation of Film Formation of Mixed Polymer Latex in the Water Evaporation Stage. , 2000, Journal of colloid and interface science.

[12]  O. Velev,et al.  Microstructured Porous Silica Obtained via Colloidal Crystal Templates , 1998 .

[13]  O. Velev,et al.  Porous silica via colloidal crystallization , 1997, Nature.

[14]  Orlin D. Velev,et al.  Structured porous materials via colloidal crystal templating: from inorganic oxides to metals , 2000 .

[15]  Mesostructured TiO2: ligand-stabilized synthesis and characterization , 1997 .

[16]  D. E. Yates,et al.  Control of particle size in the formation of polymer latices , 1978 .

[17]  F. Marlow,et al.  New Type of Inverse Opals: Titania With Skeleton Structure , 2003 .

[18]  Fernando Galembeck,et al.  Easy polymer latex self-assembly and colloidal crystal formation: the case of poly[styrene-co-(2-hydroxyethyl methacrylate)] , 1998 .

[19]  Clément Sanchez,et al.  Sol-gel chemistry of transition metal oxides , 1988 .

[20]  C. Sanchez,et al.  Hydrolysis of titanium alkoxides: modification of the molecular precursor by acetic acid , 1987 .

[21]  Kunio Furusawa,et al.  Assembly of Latex Particles by Using Emulsion Droplets as Templates. 1. Microstructured Hollow Spheres , 1996 .

[22]  V. Colvin,et al.  Thin Films of Macroporous Metal Oxides , 2001 .

[23]  A. Stein,et al.  Gems of Chemistry and Physics: Macroporous Metal Oxides with 3D Order , 2001 .

[24]  Vos,et al.  Preparation of photonic crystals made of air spheres in titania , 1998, Science.

[25]  T. Yoko,et al.  Preparation of TiO2 fibres by hydrolysis and polycondensation of Ti(O—i-C3H7)4 , 1986 .

[26]  Younan Xia,et al.  Monodispersed Colloidal Spheres: Old Materials with New Applications , 2000 .

[27]  Younan Xia,et al.  Fabrication and characterization of porous membranes with highly ordered three-dimensional periodic structures , 1999 .

[28]  B. E. Yoldas.  Hydrolysis of titanium alkoxide and effects of hydrolytic polycondensation parameters , 1986 .

[29]  L. Hench,et al.  The sol-gel process , 1990 .