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Kinetics of the Formation of 2D-Hexagonal Silica Nanostructured Materials by Nonionic Block Copolymer Templating in Solution

2011; American Chemical Society; Volume: 115; Issue: 39 Linguagem: Inglês

10.1021/jp200213k

1520-6106

Sabine Manet, Julien Schmitt, Marianne Impéror‐Clerc, Vladimir Zholobenko, D. Durand, Cristiano L. P. Oliveira, Jan Skov Pedersen, Christel Gervais, Niki Baccile, Florence Babonneau, Isabelle Grillo, Florian Meneau, Cyrille Rochas,

Catalytic Processes in Materials Science

The different steps of the self-assembly in solution of several 2D-hexagonal silica nanostructured SBA-15 materials have been investigated by SAXS and SANS in situ experiments. Unique quantitative information about the shape and size evolution upon time of the micellar aggregates throughout the self-assembly process is obtained using a complete model that describes well the scattering data for the various synthesis conditions. In all cases, before the precipitation of the material, the micelles shape changes from spherical to rod-like, where the structure of the rod-like micelles is linked to the structure of the 2D-hexagonal precipitated material. In addition, the kinetics of hydrolysis of the inorganic precursor (TEOS) has been determined by in situ Raman spectroscopy. More specifically, by comparing synthesis made with different acids (HNO(3), HBr, HCl, H(2)SO(4), and H(3)PO(4)), it is found that materials prepared using the "salting-out" anions (SO(4)(2-) and H(2)PO(4)(-)) are much better ordered than with the "salting-in" anions (NO(3)(-) and Br(-)).