Map of gel times for three phase region tetraethoxysilane, ethanol and water

Chang, Shih-Ju; Ring, Terry A.

doi:10.1016/s0022-3093(05)80593-9

Cited by 36 publications

(21 citation statements)

References 8 publications

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“…The water/silane ratio in solution has a significant influence on gelation times 4,22 , and is proportional to the rate of hydrolysis 28,29 . As a result, water content determines the kinetics of polycondensation 24 , and the solids formed differ in their microstructure 28 and pore size distribution 4,30 .…”

Section: Scheme 1: Reaction Equations For Hydrolysis Condensation Amentioning

confidence: 99%

“…By only considering hydroxysilanes, these studies do not account for modeling the hydrolysis reaction, which under neutral conditions is the rate limiting step 35 in polycondensation. As mentioned above, typical precursor solutions contain mixtures of alkoxysilane, solvent, and water 5,22 , and these compositions have not been considered.…”

Section: Scheme 1: Reaction Equations For Hydrolysis Condensation Amentioning

confidence: 99%

See 1 more Smart Citation

Reactive modeling of the initial stages of alkoxysilane polycondensation: effects of precursor molecule structure and solution composition

Deetz

Faller

2015

Soft Matter

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Section: Scheme 1: Reaction Equations For Hydrolysis Condensation Amentioning

confidence: 99%

Section: Scheme 1: Reaction Equations For Hydrolysis Condensation Amentioning

confidence: 99%

Reactive modeling of the initial stages of alkoxysilane polycondensation: effects of precursor molecule structure and solution composition

Deetz

Faller

2015

Soft Matter

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“…This method is frequently adopted in membrane synthesis or membrane pore modification due to its controllability and homogeneity [24,30,[36][37][38], and it includes various steps such as sol preparation, gel formation, drying and thermal treatment. Many types of silicon alkoxide precursors have been utilized, but the clear majority of research describes work using tetraethoxysilane (TEOS) [39][40][41]. The sol gel synthesis has been well described in a variety of reference materials [42], and so briefly it involves the hydrolysis (Equation (3)) and condensation reactions (Equations (4) and (5)) of a metal alkoxides to form a network.…”

Section: Features Of Silica Based Membranes For Desalinationmentioning

confidence: 99%

Microporous Silica Based Membranes for Desalination

Elma

Yacou

Wang

et al. 2012

Water

103

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Abstract:This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes.

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“…Since the thermal conductivity of aerogels is related to their nanoporous structure, it may be possible to improve the thermal conductivity of these silicone aerogels by appropriate engineering of the material during sol-gel processing. For TEOS based aerogels extensive research [8][9][10][11][12][13][14] has been reported on the influence of sol-gel process parameters, such as the use of different precursors, catalysts for hydrolysis and condensation, the ratio of precursor to solvent, the ratio of precursor to water, catalyst concentration, aging time, solvents for gel surface modification and drying methods. However, for MTMS based silicone aerogels far less is known about how porous structures respond to solgel processing parameters.…”

Section: Introductionmentioning

confidence: 99%

Control of porous structure in flexible silicone aerogels produced from methyltrimethoxysilane (MTMS): the effect of precursor concentration in sol–gel solutions

Mao

Russell

2015

J Mater Sci

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This is a repository copy of Control of porous structure in flexible silicone aerogels produced from methyltrimethoxysilane (MTMS) ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Control of porous structure in flexible silicone aerogels produced from methyltrimethoxysilane (MTMS): The effect of precursor concentration in solgel solutions Control of porous structure in flexible silicone aerogels produced from methyltrimethoxysilane (MTMS): The effect of precursor concentration in sol- AbstractControllable nanoporous structure in MTMS based silicone aerogels is required to improve their thermal conductivity. Silicone aerogels were formed in a two-step acid-base catalysed sol-gel process combined with supercritical drying. The influence of MTMS concentration, specifically the molar ratio of methanol:MTMS and water: MTMS in the sol-gel process was studied in relation to the porous structure of resultant silicone aerogels. Samples were characterised to determine the dimensions of micro, meso and macro-pore structure by means of both nitrogen gas adsorption-desorption for detection of pores less than 300 nm and by analysis of FEG-SEM images for pores greater than 300 nm. Porosity, pore volume distribution and BET surface area in the silicone aerogels were all found to be influenced by adjustment of the molar ratio of methanol:MTMS and the molar ratio of water:MTMS during sol-gel processing.

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Map of gel times for three phase region tetraethoxysilane, ethanol and water

Cited by 36 publications

References 8 publications

Reactive modeling of the initial stages of alkoxysilane polycondensation: effects of precursor molecule structure and solution composition

Reactive modeling of the initial stages of alkoxysilane polycondensation: effects of precursor molecule structure and solution composition

Microporous Silica Based Membranes for Desalination

Control of porous structure in flexible silicone aerogels produced from methyltrimethoxysilane (MTMS): the effect of precursor concentration in sol–gel solutions

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