Synthesis and characterization of transparent silica-based aerogels using methyltrimethoxysilane precursor

Nogami, Masayuki; Hotta, Shohei; Kugimiya, Kazumasa; Matsubara, Hideaki

doi:10.1007/s10971-010-2282-x

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…Approx 20% of the weight of the materials was due to adsorbed water (Table 3), which could be eliminated after 4 to 5 h treatment under primary vacuum at 80 °C. To decrease the hydrophilic character of SG0 monoliths, 32,59,60 different amounts of TMOS-OC (2 → 5%, SG0-OC) 61 were added to the initial sols. The octyl substituent accelerates the rate of hydrolysis by a Data corresponding to the materials used for spectroscopic studies (for photooxidation tests see Tables 6 and 7).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Transparent Organosilica Photocatalysts Activated by Visible Light: Photophysical and Oxidative Properties at the Gas–Solid Interface

Arzoumanian

Ronzani

Trivella

et al. 2013

ACS Appl. Mater. Interfaces

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The photophysical properties of several photosensitizers (PSs) included or grafted in silica monoliths were compared to their properties in solution. The effects of the solid support on their steady-state and transient absorption spectra, on their quantum yields of singlet oxygen ((1)O2) production, and on their ability to photoinduce the oxidation of dimethylsulfide (DMS) were investigated. Two cyanoanthracene derivatives (9,14-dicyanobenzo[b]triphenylene, DBTP, and 9,10-dicyanoanthracene, DCA), as well as three phenothiazine dyes (methylene blue, MB(+), new methylene blue, NMB(+), methylene violet, MV), were encapsulated in silica, analyzed and compared to two reference PSs (perinaphthenone, PN and rose bengal, RB). A DBTP derivative (3-[N-(N″-triethoxysilylpropyl-N'-hexylurea)]carboxamido-9,14-dicyanobenzo[b]triphenylene, 3) was also prepared and grafted onto silica. Thanks to the transparency and the free-standing shape of the monoliths, the complete spectroscopic characterization of the supported PSs was carried out directly at the gas-solid interface. The influence of the silica network, the PS, and the adsorption/grafting link between the PS and silica was investigated. The effects of PS concentration, gaseous atmosphere, humidity, and hydrophobicity on the production of (1)O2 were analyzed. With all PSs, (1)O2 production was very efficient (quantum yields of (1)O2 production, relative to PN, between 0.6 and 1), and this species was the only one involved in the pollutant photooxidation. The influence of the matrix on the PSs' photophysics could be considered as negligible. In contrast, the matrix effect on DMS photooxidation was extremely important: the gas diffusion inside the porous structure, and thus, the photoactivity of the materials, strictly depended on silica's surface area and porosity. Our results highlight the suitability of these silica structures as inert supports for the study of the photosensitizing properties at the gas-solid interface. Moreover, thanks to the adsorption properties of the matrix, the synthesized materials can be used as microphotoreactor for the (1)O2-mediated oxidation of volatile pollutants.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Transparent Organosilica Photocatalysts Activated by Visible Light: Photophysical and Oxidative Properties at the Gas–Solid Interface

Arzoumanian

Ronzani

Trivella

et al. 2013

ACS Appl. Mater. Interfaces

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“…Due to high cost of this type of drying and the explosion danger, along with the studies on supercritical drying, research on forming silica aerogel dried in conditions of atmospheric pressure were conducted. Here a modification of the gel called silylation is performed before drying where the hydroxide groups –OH localized on the silica gel frame are replaced by inert hydrocarbon groups –O–Si(CH 3 ) [ 47 , 48 , 49 , 50 ]. Most commonly this modification is made with the use of trimethylchlorosilane (TMCS), hexamethyldisiloxane (HMDSO), hexamethyldisilazane (HMDZ), methyltrietoxysilane (MTES), or methyltrimethoxysilane (MTMS).…”

Section: Synthesis Of Silica Aerogelsmentioning

confidence: 99%

Recent Advances in Research on the Synthetic Fiber Based Silica Aerogel Nanocomposites

Ślosarczyk

2017

Nanomaterials

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The presented paper contains a brief review on the synthesis and characterization of silica aerogels and its nanocomposites with nanofibers and fibers based on a literature study over the past twenty years and my own research. Particular attention is focused on carbon fiber-based silica aerogel nanocomposites. Silica aerogel is brittle in nature, therefore, it is necessary to improve this drawback, e.g., by polymer modification or fiber additives. Nevertheless, there are very few articles in the literature devoted to the synthesis of silica aerogel/fiber nanocomposites, especially those focusing on carbon fibers and nanofibers. Carbon fibers are very interesting materials, namely due to their special properties: high conductivity, high mechanical properties in relation to very low bulk densities, high thermal stability, and chemical resistance in the silica aerogel matrix, which can help enhance silica aerogel applications in the future.

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“…The PR–Si wet gel was transparent and flexible (Figure S2), which means that the chemically interpenetrated PR–Si gel can prevent any inhomogeneity caused by phase separation. During the solvent exchange and drying process, the swelling or the shrinkage usually occurred and caused stress to form microcracks in the gel, resulting in broken gel or transparency decrement. , In this work, the silica particles which grafted on CDs can slide along the PEG chain to relax the internal stress as needed, which is helpful to prevent the crack during solvent exchange.…”

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confidence: 99%

One-Pot Synthesis and Characterization of Polyrotaxane–Silica Hybrid Aerogel

et al. 2017

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A novel kind of polyrotaxane–silica hybrid aerogel is successfully prepared via one-pot sol–gel synthesis in this work. The polyrotaxane can chemically interpenetrate with Si particles homogeneously in nanoscale, so as to shorten the gelation time and construct a flexible and mechanically strong skeleton. The supramolecular effect ascribable to the sliding motion of cyclic components in polyrotaxane is introduced into the hybrid aerogel for the first time. Compared with the brittle pure silica aerogel, the obtained polyrotaxane–silica hybrid aerogels show very low density, low thermal conductivity, and more than two orders magnitude improvement in the compression strength without compromising transparency.

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Synthesis and characterization of transparent silica-based aerogels using methyltrimethoxysilane precursor

Cited by 6 publications

References 18 publications

Transparent Organosilica Photocatalysts Activated by Visible Light: Photophysical and Oxidative Properties at the Gas–Solid Interface

Transparent Organosilica Photocatalysts Activated by Visible Light: Photophysical and Oxidative Properties at the Gas–Solid Interface

Recent Advances in Research on the Synthetic Fiber Based Silica Aerogel Nanocomposites

One-Pot Synthesis and Characterization of Polyrotaxane–Silica Hybrid Aerogel

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