Fluorine-induced hydrophobicity in silica aerogels

Tillotson, Thomas M.; Foster, Kenneth G.; Reynolds, John G.

doi:10.1016/j.jnoncrysol.2004.08.233

Cited by 21 publications

(10 citation statements)

References 19 publications

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“…[12][13][14] Spectroscopic and elemental analyses verifies the CH 2 CH 2 CF 3 group is incorporated into the silica framework somehow. The formulation used here was also found to absorb only 2.5 wt % water (in a water saturated atmosphere) over a period of 2+ months indicating the aerogel is highly hydrophobic.…”

Section: Resultsmentioning

confidence: 92%

Engineering Surface Functional Groups on Silica Aerogel for Enhanced Cleanup of Organics from Produced Water

Love

Hanna

Reynolds

2005

Separation Science and Technology

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Engineering the surface functional groups of silica aerogels has resulted in greatly enhanced separation capabilities. This approach is used to design a material that is effective at reducing the dissolved organic components of produced water. This study reports the initial results of removing dissolved hydrophobic organics using a hydrophobic (CH 2 CH 2 CF 3 ) surface group on the silica aerogel. The 30% by wt formulation CF 3 -aerogel was able to adsorb dissolved organic species with log K ow > 2.0, with adsorption affinity increasing with increasing log K ow . Seawater salinities did not have a large affect on the adsorption of aromatic compounds. Most dissolved aromatics and organic acids with the same log K ow that were tested had differing affinities for the CF 3 -aerogel, with the aromatics affinity being greater. These results show the utility of modifying the aerogel surface hydrophobicity for absorbing hydrophobic dissolved organic compounds.

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Section: Resultsmentioning

confidence: 92%

Engineering Surface Functional Groups on Silica Aerogel for Enhanced Cleanup of Organics from Produced Water

Love

Hanna

Reynolds

2005

Separation Science and Technology

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“…8,9 These low surface energy materials can be obtained by uorinating the silica gel through different chemical transformations post-gelation or by adding a uorinated reactive silane as a co-monomer during the sol-gel process. 10,11 For example, Lermontov et al acetylated amine terminated aerogels with the readily available reagent, methyl triuoroacetate. 12 The authors also synthesized a uori-nated reactive silane and employed it as a co-monomer with tetraethyl orthosilicate (TEOS) to prepare uorinated aerogels and it was determined that the method of uorine incorporation produced samples with different specic surface areas.…”

Section: -7mentioning

confidence: 99%

Synthesis and characterization of partially fluorinated aerogels and xerogels from environmentally-compatible precursors

et al. 2017

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A new fluorocyclic silane monomer was prepared from environmentally benign and commercially available starting reagents in two, high yielding steps. The monomer was characterized by multi-nuclear NMR ( 1 H, 13 C, 19 F, and 29 Si). The monomer was used in the preparation of the first known fluorocyclic aerogels and xerogels. Due to the hydrophobic nature of the fluorocyclic monomer, a modified sol-gel synthesis was utilized in which a minimum amount of water was used. The mol% of the fluorocyclic monomer was systematically varied in both types of silica gels and the effects on the properties of the aerogels and xerogels was analyzed by scanning electron microscopy, BET surface area measurements, differential scanning calorimetry, and thermogravimetric analysis. It was determined that in both aerogels and xerogels, increasing the mol% of the fluorocyclic monomer resulted in condensed materials (i.e., pore collapse). Increased monomer concentration affected the gels thermal stability as the monomer is more susceptible to thermal decomposition than the silica gel. Pore collapse accelerates this effect as the condensed medium dissipates heat less efficiently.

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“…In fact, it is general that the molecular weight is related to the degree of condensation. It has been reported that the copolymerization reaction of BTMSE with higher alkyl units reduces the reactivity due to steric hindrance, and the stacking of higher alkyl groups, which usually retards the condensation rate during sol-gel reaction [19][20][21]. As a result, the alkyl chain content incorporated into copolymers decreases as the length of alkyl chain elongates.…”

Section: Resultsmentioning

confidence: 99%

Characteristics of poly(alkyl silsesquioxane) thin films prepared from chemically linked alkyl units

Cham¹,

Kim

Jung³

2006

Journal of Non-Crystalline Solids

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Fluorine-induced hydrophobicity in silica aerogels

Cited by 21 publications

References 19 publications

Engineering Surface Functional Groups on Silica Aerogel for Enhanced Cleanup of Organics from Produced Water

Engineering Surface Functional Groups on Silica Aerogel for Enhanced Cleanup of Organics from Produced Water

Synthesis and characterization of partially fluorinated aerogels and xerogels from environmentally-compatible precursors

Characteristics of poly(alkyl silsesquioxane) thin films prepared from chemically linked alkyl units

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