Infrared spectroscopic analysis of siloxane network modification of mesoporous silica film by silylation and cesium doping

Kayaba, Yasuhsia; Kohmura, Kazuo; Tanaka, Hirofumi; Seino, Yutaka; Ohdaira, Toshiyuki; Chikaki, Shinichi; Kikkawa, Takamaro

doi:10.1016/j.tsf.2010.08.109

Cited by 8 publications

(16 citation statements)

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“…Silica polymerization is important in the preparation of adsorbents, ceramics, zeolites, catalysts, papers, coatings, and a number of other materials. − The solidified silica should possess appropriate pore size, surface area, mechanical strength, tackiness, hydrophobicity, elasticity, and other properties which are optimized by varying ingredients, reaction conditions, and post-treatment techniques. In support of these efforts the chemistry of silica and silicates has been intensively studied for over a century. − Yet even the latest literature contains many related studies, apparently because several aspects are still not understood at the molecular level. − …”

Section: Introductionmentioning

confidence: 99%

²⁹Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

et al. 2011

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The molecular structures of various silica gels are compared using 29 Si NMR and laser Raman spectroscopy. When gels are deposited onto a porous organic resin from tetra ethyl orthosilicate, TEOS, at acidic or basic conditions, their appearance and physical properties show dramatic differences. It is demonstrated that these differences are associated with distinct Q 3 /Q 4 SiÀOÀSi connectivity ratios in the two materials although both are mainly constructed from 3 and 5 member siloxane rings (3R and 5R). Comparative NMR and Raman spectroscopic experiments on these gels and related model calculations indicate that Raman is disproportionally more sensitive for Q 1 and Q 2 connectivities than for Q 3 and Q 4 . This is an important new aspect to consider in the Raman identification of Q n connectivities in amorphous silicates. It is also shown that the molecular structures of TEOS based gels differ when made in the presence or absence of the porous organic substrate. Hence the substrate seems to exert structure directing effect. Characteristic structural differences have been identified also between the TEOS based silica gels and gels prepared from a commercial 3.22 SiO 2 /Na 2 O ratio aqueous sodium silicate solution. Moreover the structure of an "as synthesized" base set Na-silicate hydrogel is also different from that of its acid set counterpart: the former gel contains mainly 4 and 5 member and larger siloxane rings while the latter one virtually does not show any ring-associated Raman vibration. This result provides direct experimental support for the decades-old theoretical predictions that physical differences of acid and base set gels might be related to their ring and branched linear chain structures, respectively. We also demonstrate that the acid set gel gradually develops siloxane rings during its washing and aging procedures.

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Section: Introductionmentioning

confidence: 99%

²⁹Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

et al. 2011

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“…The physical and chemical properties of silica can be modified by integration of different elements into the siloxane network 4–6. Phosphosilicate is a silicate‐based material that has high biocompatibility and nontoxic character compared with pure silica.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Large‐Sized Mesoporous Phosphosilicate Thin Film through Evaporation‐Induced Polymeric Micelle Assembly

Bastakoti

Imura

et al. 2014

Chemistry An Asian Journal

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A triblock copolymer, poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-b-P2VP-b-PEO) was used as a soft template to synthesize large-sized mesoporous phosphosilicate thin films. The kinetically frozen PS core stabilizes the micelles. The strong interaction of the inorganic precursors with the P2VP shell enables the fabrication of highly robust walls of phosphosilicate and the PEO helps orderly packing of the micelles during solvent evaporation. The molar ratio of phosphoric acid and tetraethyl orthosilicate is crucial to achieve the final mesostructure. The insertion of phosphorus species into the siloxane network is studied by (29) Si and (31) P MAS NMR spectra. The mesoporous phosphosilicate films exhibit steady cell adhesion properties and show great promise as excellent materials in bone-growth engineering applications.

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“…For a quantitative discussion, one of the authors has been developed a nondestructive evaluation technique of ionic vibration spectrum. 25,26 In this work, the FTIR spectrum of the spin-on thin film derived from the suspension of nanocrystalline MEL pure silica zeolite is measured, and the complex dielectric function concerning the ionic vibration of siloxane bonding is calculated. On the basis of the data, the siloxane bonding structures are discussed.…”

Section: Introductionmentioning

confidence: 99%

Ionic Vibration Spectrum of Nanocrystalline MEL Pure Silica Zeolite Film

et al. 2011

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Skeletal siloxane bonding structure of nanocrystalline MEL pure silica zeolite film was investigated. Nanocrystalline zeolite (nc-zeolite) suspension was prepared by the two-stage hydrothermal treatment, and thin film was obtained by spin-coating. After a quantitative analysis of Fourier-transform infrared spectra with the variable incidence angles of light probe, skeletal complex dielectric function concerning the siloxane bond vibration was derived in the 1400–400 cm–1 range. Then, the widening of the AS1-(LO-TO) frequency splitting width and the enhancement of the normalized integrated oscillator strength of AS vibration mode were observed in the nc-zeolite film in comparison with those of sol–gel derived amorphous silica film. Those improvements must be attributed to the increased siloxane network connectivity and the crystal structure of zeolite. The effect of the UV assist anneal was also discussed.

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Infrared spectroscopic analysis of siloxane network modification of mesoporous silica film by silylation and cesium doping

Cited by 8 publications

References 40 publications

²⁹Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

²⁹Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

Synthesis of a Large‐Sized Mesoporous Phosphosilicate Thin Film through Evaporation‐Induced Polymeric Micelle Assembly

Ionic Vibration Spectrum of Nanocrystalline MEL Pure Silica Zeolite Film

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Infrared spectroscopic analysis of siloxane network modification of mesoporous silica film by silylation and cesium doping

Cited by 8 publications

References 40 publications

29Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

29Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

Synthesis of a Large‐Sized Mesoporous Phosphosilicate Thin Film through Evaporation‐Induced Polymeric Micelle Assembly

Ionic Vibration Spectrum of Nanocrystalline MEL Pure Silica Zeolite Film

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²⁹Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate

²⁹Si NMR and Raman Glimpses into the Molecular Structures of Acid and Base Set Silica Gels Obtained from TEOS and Na-Silicate