Effect of preparation conditions on the physical and hydrophobic properties of two step processed ambient pressure dried silica aerogels

Rao, A. Parvathy; Pajonk, G.M.

doi:10.1007/s10853-005-2853-3

Cited by 114 publications

(53 citation statements)

References 32 publications

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“…Silica Aerogels have porosities of 80-99.8% and pore sizes in the range of 10 nm to 70 nm [1]. Consequently, these gels are attractive for thermal decoupling due to a very low thermal conductivity of 0.02 W/mK [1] and have an extremely large inner surface area of up to 1000 m 2 /g.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, these gels are attractive for thermal decoupling due to a very low thermal conductivity of 0.02 W/mK [1] and have an extremely large inner surface area of up to 1000 m 2 /g. Furthermore, silica aerogels are chemically inert as they consist only of silicone oxide (SiO2) but also transparent with an optical transmission of 90%.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, silica aerogels are chemically inert as they consist only of silicone oxide (SiO2) but also transparent with an optical transmission of 90%. By surface modification with hexamethyldisilazane (HMDS), the gels become superhydrophobic [1]. Therefore, the integration of silica aerogels in microchips is of interest to many MEMS-applications like catalysis reactions, surface modifications (e.g., coating with antibodies), optical measurements or as interface between gases and liquids to solve the gases (e.g., cell cultivation for lab-on-a-chip applications).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Integration of Silica Aerogels in Microfluidic Chips

Reede

Bunge

Vellekoop

2017

Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017

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This paper reports a method to integrate silica aerogels monolithically in microfluidic chips. Silica Aerogel is a highly porous bulk material. The gel was synthesized from tetraethyl orthosilicate by a sol-gel process. Polyethylene glycol and an extended aging period were used to strengthen the matrix minimizing gel shrinkage. This technique allows alcogel structures with high strength and stiffness that withstand high pressure during the subcritical drying process. Hexamethyldisilazane provides for hydrophobizing and prevents the formation of siloxane bonds during the drying process. The resulting transparent aerogels reach porosities of 85%, pore diameters around 50 nm and contact angles of 136°.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Integration of Silica Aerogels in Microfluidic Chips

Reede

Bunge

Vellekoop

2017

Proceedings of Eurosensors 2017, Paris, France, 3–6 September 2017

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“…Recently, silica aerogel were synthesized at ambient pressure via solvent exchange and surface modification of wet gels [21][22][23][24]. Also, synthesis using cheap silica precursor is suggested in the literature [25].…”

Section: Introductionmentioning

confidence: 99%

Amine impregnated porous silica gel sorbents synthesized from water–glass precursors for CO2 capturing

Minju

Abhilash

Nair

et al. 2015

Chemical Engineering Journal

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In this work, porous silica gel-solid beads have been made from economically affordable water-glass precursors via sol-gel nano casting technique. A stable nanometric silica sol was prepared first from water glass and studied for surface potential and sol to gel transition. A free-flow, injectable gel was obtained upon aging the sol which was then assembled into spherical silica beads in a chemical bath. A surface area of 304.7 m 2 g -1 was obtained for water glass derived silica gel beads. These gel beads were impregnated with 3-aminopropyltrimethoxysilane (APTMS) and polyethylenimine (PEI) active functional groups at different percentages for turning the gel beads as sorbents for CO 2 gas adsorption. The effect of amine loading on the thermal stability, morphology as well as porosity was studied and was correlated with CO 2 adsorption values. Depending upon the amount of amine loaded in the gel support CO 2 uptake was found varied. These amine modified silica gel porous adsorbents showed CO 2 adsorption capacity at temperatures as low as 100 o C; samples modified with 15 wt% PEI had CO 2 adsorption capacity of 1.16 mmol g -1 at 50 o C.

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“…The sol-gel method has been widely used to prepare the silica wet gels in many excellent research and review papers [15,24,25]. A series of factors including precursors, catalysts, molar ratios of initial materials and reaction temperature have been studied.…”

Section: Introductionmentioning

confidence: 99%

Low-cost and fast synthesis of nanoporous silica cryogels for thermal insulation applications

Liu

Tanaka

et al. 2012

Science and Technology of Advanced Materials

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Nanoporous silica cryogels with a high specific surface area of 1095 m 2 g −1 were fabricated using tert-butyl alcohol as a reaction solvent, via a cost-effective sol-gel process followed by vacuum freeze drying. The total time of cryogel production was reduced markedly to one day. The molar ratio of solvent/precursor, which was varied from 5 to 13, significantly affected the porous structure and thermal insulating properties of the cryogels. The silica cryogels with low densities in the range of 0.08-0.18 g cm −3 and thermal conductivities as low as 6.7 mW (m · K) −1 at 100 Pa and 28.3 mW (m · K) −1 at 10 5 Pa were obtained using this new technique.

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Effect of preparation conditions on the physical and hydrophobic properties of two step processed ambient pressure dried silica aerogels

Cited by 114 publications

References 32 publications

Integration of Silica Aerogels in Microfluidic Chips

Integration of Silica Aerogels in Microfluidic Chips

Amine impregnated porous silica gel sorbents synthesized from water–glass precursors for CO2 capturing

Low-cost and fast synthesis of nanoporous silica cryogels for thermal insulation applications

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