Influence of Monomer Connectivity, Network Flexibility, and Hydrophobicity on the Hydrothermal Stability of Organosilicas

Albertine Petra Dral, C. Lievens, Johan E. ten Elshof (Corresponding Author)

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Abstract

It is generally assumed that the hydrothermal stability of organically modified silica networks is promoted by high monomer connectivity, network flexibility, and the presence of hydrophobic groups in the network. In this study a range of organosilica compositions is synthesized to explore the extent to which these factors play a role in the hydrothermal dissolution of these materials. Compositions were synthesized from hexafunctional organically bridged silsesquioxanes (OR1)3Si–R–Si(OR1)3 (R = −CH2–, –C2H4–, –C6H12–, –C8H16–, –p-C6H4–; R1 = −CH3, –C2H5), tetrafunctional (OEt)2Si(CH3)–C2H4–Si(CH3)(OEt)2 and Si(OEt)4, trifunctional silsesquioxanes R′-Si(OMe)3 (R′=CH3, n-C3H7, cyclo-C6H11, phenyl), and bifunctional Si(i-C3H7)2(OMe)2. The bond strain, connectivity and hydroxyl concentration of all networks were estimated using 29Si cross-polarized magic angle spinning nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The hydrophilicity was characterized by monitoring the water uptake of the materials in moisture treatments with thermogravimetric analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The resistance of each network against hydrothermal dissolution in a water/1,5-pentanediol mixture at 80 °C and pH 1, 7, and 13 was analyzed with inductively coupled plasma optical emission spectroscopy and X-ray fluorescence. Bond strain appears to significantly increase the tendency to dissolve under hydrothermal conditions. The stabilizing influences of increased connectivity and hydrophobicity were found to be weak.
Original languageEnglish
Pages (from-to)5527-5536
Number of pages10
JournalLangmuir
Volume33
Issue number22
DOIs
Publication statusPublished - 2017

Fingerprint

Hydrophobicity
hydrophobicity
Fourier transform infrared spectroscopy
flexibility
Dissolution
monomers
Monomers
Optical emission spectroscopy
Magic angle spinning
Water
Hydrophilicity
Inductively coupled plasma
Chemical analysis
Silicon Dioxide
Hydroxyl Radical
Thermogravimetric analysis
Differential scanning calorimetry
Moisture
Fluorescence
Silica

Cite this

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title = "Influence of Monomer Connectivity, Network Flexibility, and Hydrophobicity on the Hydrothermal Stability of Organosilicas",
abstract = "It is generally assumed that the hydrothermal stability of organically modified silica networks is promoted by high monomer connectivity, network flexibility, and the presence of hydrophobic groups in the network. In this study a range of organosilica compositions is synthesized to explore the extent to which these factors play a role in the hydrothermal dissolution of these materials. Compositions were synthesized from hexafunctional organically bridged silsesquioxanes (OR1)3Si–R–Si(OR1)3 (R = −CH2–, –C2H4–, –C6H12–, –C8H16–, –p-C6H4–; R1 = −CH3, –C2H5), tetrafunctional (OEt)2Si(CH3)–C2H4–Si(CH3)(OEt)2 and Si(OEt)4, trifunctional silsesquioxanes R′-Si(OMe)3 (R′=CH3, n-C3H7, cyclo-C6H11, phenyl), and bifunctional Si(i-C3H7)2(OMe)2. The bond strain, connectivity and hydroxyl concentration of all networks were estimated using 29Si cross-polarized magic angle spinning nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The hydrophilicity was characterized by monitoring the water uptake of the materials in moisture treatments with thermogravimetric analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The resistance of each network against hydrothermal dissolution in a water/1,5-pentanediol mixture at 80 °C and pH 1, 7, and 13 was analyzed with inductively coupled plasma optical emission spectroscopy and X-ray fluorescence. Bond strain appears to significantly increase the tendency to dissolve under hydrothermal conditions. The stabilizing influences of increased connectivity and hydrophobicity were found to be weak.",
author = "Dral, {Albertine Petra} and C. Lievens and {ten Elshof}, {Johan E.}",
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Influence of Monomer Connectivity, Network Flexibility, and Hydrophobicity on the Hydrothermal Stability of Organosilicas. / Dral, Albertine Petra; Lievens, C.; ten Elshof, Johan E. (Corresponding Author).

In: Langmuir, Vol. 33, No. 22, 2017, p. 5527-5536.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Influence of Monomer Connectivity, Network Flexibility, and Hydrophobicity on the Hydrothermal Stability of Organosilicas

AU - Dral, Albertine Petra

AU - Lievens, C.

AU - ten Elshof, Johan E.

PY - 2017

Y1 - 2017

N2 - It is generally assumed that the hydrothermal stability of organically modified silica networks is promoted by high monomer connectivity, network flexibility, and the presence of hydrophobic groups in the network. In this study a range of organosilica compositions is synthesized to explore the extent to which these factors play a role in the hydrothermal dissolution of these materials. Compositions were synthesized from hexafunctional organically bridged silsesquioxanes (OR1)3Si–R–Si(OR1)3 (R = −CH2–, –C2H4–, –C6H12–, –C8H16–, –p-C6H4–; R1 = −CH3, –C2H5), tetrafunctional (OEt)2Si(CH3)–C2H4–Si(CH3)(OEt)2 and Si(OEt)4, trifunctional silsesquioxanes R′-Si(OMe)3 (R′=CH3, n-C3H7, cyclo-C6H11, phenyl), and bifunctional Si(i-C3H7)2(OMe)2. The bond strain, connectivity and hydroxyl concentration of all networks were estimated using 29Si cross-polarized magic angle spinning nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The hydrophilicity was characterized by monitoring the water uptake of the materials in moisture treatments with thermogravimetric analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The resistance of each network against hydrothermal dissolution in a water/1,5-pentanediol mixture at 80 °C and pH 1, 7, and 13 was analyzed with inductively coupled plasma optical emission spectroscopy and X-ray fluorescence. Bond strain appears to significantly increase the tendency to dissolve under hydrothermal conditions. The stabilizing influences of increased connectivity and hydrophobicity were found to be weak.

AB - It is generally assumed that the hydrothermal stability of organically modified silica networks is promoted by high monomer connectivity, network flexibility, and the presence of hydrophobic groups in the network. In this study a range of organosilica compositions is synthesized to explore the extent to which these factors play a role in the hydrothermal dissolution of these materials. Compositions were synthesized from hexafunctional organically bridged silsesquioxanes (OR1)3Si–R–Si(OR1)3 (R = −CH2–, –C2H4–, –C6H12–, –C8H16–, –p-C6H4–; R1 = −CH3, –C2H5), tetrafunctional (OEt)2Si(CH3)–C2H4–Si(CH3)(OEt)2 and Si(OEt)4, trifunctional silsesquioxanes R′-Si(OMe)3 (R′=CH3, n-C3H7, cyclo-C6H11, phenyl), and bifunctional Si(i-C3H7)2(OMe)2. The bond strain, connectivity and hydroxyl concentration of all networks were estimated using 29Si cross-polarized magic angle spinning nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The hydrophilicity was characterized by monitoring the water uptake of the materials in moisture treatments with thermogravimetric analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The resistance of each network against hydrothermal dissolution in a water/1,5-pentanediol mixture at 80 °C and pH 1, 7, and 13 was analyzed with inductively coupled plasma optical emission spectroscopy and X-ray fluorescence. Bond strain appears to significantly increase the tendency to dissolve under hydrothermal conditions. The stabilizing influences of increased connectivity and hydrophobicity were found to be weak.

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DO - 10.1021/acs.langmuir.7b00971

M3 - Article

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JO - Langmuir

JF - Langmuir

SN - 0743-7463

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