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Silica-block copolymer hybrids

Time-resolved in situ Small Angle Neutron Scattering (SANS) investigations have provided direct experimental evidence for the initial steps in the formation of the SBA-15 mesoporous material, prepared using the non-ionic tri-block copolymer Pluronic 123 and TEOS as silica precursor. Upon time, three steps take place during the cooperative self-assembly of the Pluronic micelles and the silica species. First, the hydrolysis of TEOS is completed, without modifications of the Pluronic spherical micelles. Then, when silica species begin to interact with the micelles, a transformation from spherical to cylindrical micelles takes place before the precipitation of the ordered SBA-15 material. Lastly, the precipitation occurs and hybrid cylindrical micelles assemble into the two-dimensional hexagonal structure of SBA-15. [Pg.53]

Figure 2 Evolution of the neutron scattering intensities with time. Only spherical micelles of P123 block copolymer are present in the synthesis mixture within the first few minutes of the reaction (300 s), during the hydrolysis of the silica precursor. Then, hybrid organic-inorganic cylindrical micelles are detected (300-1400 s). The SBA-15 hexagonal phase is formed when the precipitation occurs, after 1400 s. Figure 2 Evolution of the neutron scattering intensities with time. Only spherical micelles of P123 block copolymer are present in the synthesis mixture within the first few minutes of the reaction (300 s), during the hydrolysis of the silica precursor. Then, hybrid organic-inorganic cylindrical micelles are detected (300-1400 s). The SBA-15 hexagonal phase is formed when the precipitation occurs, after 1400 s.
The first part on nanostructured amorphous hybrid materials is divided in two sections. First, new findings on coassembly mechanisms of mesostmetured block copolymer-silica-type hybrids are described. More specifically, the influence of nanoparticle... [Pg.600]

Park HB, Kim JK, Nam SY, Lee YM (2003) Imide-siloxane block copolymer/silica hybrid membranes preparation, characterization and gas separation properties. J Membr... [Pg.183]

See other pages where Silica-block copolymer hybrids is mentioned: [Pg.131]    [Pg.131]    [Pg.632]    [Pg.155]    [Pg.60]    [Pg.15]    [Pg.60]    [Pg.601]    [Pg.609]    [Pg.861]    [Pg.1820]    [Pg.364]    [Pg.28]    [Pg.43]    [Pg.141]    [Pg.232]    [Pg.35]    [Pg.37]    [Pg.102]    [Pg.261]    [Pg.861]    [Pg.485]    [Pg.287]    [Pg.291]    [Pg.294]    [Pg.302]    [Pg.554]    [Pg.351]    [Pg.274]    [Pg.690]    [Pg.107]    [Pg.60]    [Pg.239]    [Pg.330]    [Pg.249]    [Pg.123]    [Pg.151]    [Pg.6311]    [Pg.189]    [Pg.771]    [Pg.435]    [Pg.278]    [Pg.380]    [Pg.358]    [Pg.87]    [Pg.88]   
See also in sourсe #XX -- [ Pg.576 , Pg.618 ]



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