Boettcher SW, Bartl MH, Hu JG, Stucky GD. Structural Analysis of Hybrid Titania-Based Mesostructured Composites.
J Am Chem Soc 2005;
127:9721-30. [PMID:
15998076 DOI:
10.1021/ja050753r]
[Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-optical-quality titania-based mesostructured films with cubic or 2D-hexagonal symmetry were fabricated by combining trifluoroacetate (TFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) copolymers. The distribution, dynamics, and local environments of the TFA-modified titania, PEO, and PPO components of the hybrid were investigated. IR/Raman spectroscopy, in situ small-angle X-ray scattering, and transmission electron microscopy studies indicate that TFA coordinates the titanium center and forms a stable complex that is subsequently organized by the block copolymer species into ordered mesostructures. Solid-state NMR (19)F-->(1)H cross-polarization, (13)C{(1)H} two-dimensional heteronuclear correlation, and (1)H relaxation techniques were used to determine that PEO is predominantly incorporated within the TFA-modified titania, and that PPO environments encompass both microphase separated regions and interfacial regions composed of mixed PPO and TFA-modified titania. NMR (19)F multiple-quantum spin counting measurements suggest that -CF(3) groups of the trifluoroacetate ligands do not form clusters but instead randomly distribute within the inorganic component of the hybrid.
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