Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation

Albertine Petra Dral, Kristianne Tempelman, Emiel Kappert, Louis Winnubst, Nieck Edwin Benes, Johan E. ten Elshof

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Abstract

Hybrid organosilica molecular sieving membranes with ethylene bridges are generally consolidated at 250–300 C for 2–3 hours, after which the material structure is assumed to be stabilized. This study shows that the consolidation process still continues at these temperatures after days to weeks. Ongoing condensation and structural evolution are studied in powders, films and gas permeation membranes derived from 1,2-bis(triethoxysilyl)ethane (BTESE) that are kept at temperatures up to 300 C for days and analyzed with in situ Fourier-transform infrared spectroscopy, 29Si cross-polarized magic angle spinning nuclear magnetic resonance, in situ spectroscopic ellipsometry, in situ gas permeation and in situ X-ray reflectivity. A continuously ongoing decrease in both silanol concentration and film thickness is observed, accompanied by changes in density, thermal expansion and micropore structure. The changes in the micropore structure are found to depend on pore size and affect the gas permeation performance of membranes. An important factor in the structural evolution is the network flexibility. Materials containing no organic bridges, short flexible bridges or long rigid bridges (derived from tetraethoxysilane (TEOS), bis(triethoxysilyl)methane (BTESM) and 1,4-bis(triethoxysilyl)benzene (BTESB), respectively) also show ongoing condensation, but their shrinkage rate is smaller as compared to BTESE-derived networks. A BTESE-derived film kept at 236 C for 12 days still shows no signs of approaching a structurally stabilized state.
Original languageEnglish
Pages (from-to)1268-1281
Number of pages14
JournalJournal of materials chemistry. A
Volume5
DOIs
Publication statusPublished - 2017

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Condensation
Ethane
Gases
Permeation
Membranes
Magic angle spinning
Spectroscopic ellipsometry
Methane
Benzene
Consolidation
Powders
Pore size
Thermal expansion
Fourier transform infrared spectroscopy
Film thickness
Ethylene
Nuclear magnetic resonance
X rays
Temperature
Polymers

Keywords

  • IR-103204
  • METIS-320562

Cite this

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title = "Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation",
abstract = "Hybrid organosilica molecular sieving membranes with ethylene bridges are generally consolidated at 250–300 C for 2–3 hours, after which the material structure is assumed to be stabilized. This study shows that the consolidation process still continues at these temperatures after days to weeks. Ongoing condensation and structural evolution are studied in powders, films and gas permeation membranes derived from 1,2-bis(triethoxysilyl)ethane (BTESE) that are kept at temperatures up to 300 C for days and analyzed with in situ Fourier-transform infrared spectroscopy, 29Si cross-polarized magic angle spinning nuclear magnetic resonance, in situ spectroscopic ellipsometry, in situ gas permeation and in situ X-ray reflectivity. A continuously ongoing decrease in both silanol concentration and film thickness is observed, accompanied by changes in density, thermal expansion and micropore structure. The changes in the micropore structure are found to depend on pore size and affect the gas permeation performance of membranes. An important factor in the structural evolution is the network flexibility. Materials containing no organic bridges, short flexible bridges or long rigid bridges (derived from tetraethoxysilane (TEOS), bis(triethoxysilyl)methane (BTESM) and 1,4-bis(triethoxysilyl)benzene (BTESB), respectively) also show ongoing condensation, but their shrinkage rate is smaller as compared to BTESE-derived networks. A BTESE-derived film kept at 236 C for 12 days still shows no signs of approaching a structurally stabilized state.",
keywords = "IR-103204, METIS-320562",
author = "Dral, {Albertine Petra} and Kristianne Tempelman and Emiel Kappert and Louis Winnubst and Benes, {Nieck Edwin} and {ten Elshof}, {Johan E.}",
year = "2017",
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language = "English",
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Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation. / Dral, Albertine Petra; Tempelman, Kristianne; Kappert, Emiel; Winnubst, Louis; Benes, Nieck Edwin; ten Elshof, Johan E.

In: Journal of materials chemistry. A, Vol. 5, 2017, p. 1268-1281.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation

AU - Dral, Albertine Petra

AU - Tempelman, Kristianne

AU - Kappert, Emiel

AU - Winnubst, Louis

AU - Benes, Nieck Edwin

AU - ten Elshof, Johan E.

PY - 2017

Y1 - 2017

N2 - Hybrid organosilica molecular sieving membranes with ethylene bridges are generally consolidated at 250–300 C for 2–3 hours, after which the material structure is assumed to be stabilized. This study shows that the consolidation process still continues at these temperatures after days to weeks. Ongoing condensation and structural evolution are studied in powders, films and gas permeation membranes derived from 1,2-bis(triethoxysilyl)ethane (BTESE) that are kept at temperatures up to 300 C for days and analyzed with in situ Fourier-transform infrared spectroscopy, 29Si cross-polarized magic angle spinning nuclear magnetic resonance, in situ spectroscopic ellipsometry, in situ gas permeation and in situ X-ray reflectivity. A continuously ongoing decrease in both silanol concentration and film thickness is observed, accompanied by changes in density, thermal expansion and micropore structure. The changes in the micropore structure are found to depend on pore size and affect the gas permeation performance of membranes. An important factor in the structural evolution is the network flexibility. Materials containing no organic bridges, short flexible bridges or long rigid bridges (derived from tetraethoxysilane (TEOS), bis(triethoxysilyl)methane (BTESM) and 1,4-bis(triethoxysilyl)benzene (BTESB), respectively) also show ongoing condensation, but their shrinkage rate is smaller as compared to BTESE-derived networks. A BTESE-derived film kept at 236 C for 12 days still shows no signs of approaching a structurally stabilized state.

AB - Hybrid organosilica molecular sieving membranes with ethylene bridges are generally consolidated at 250–300 C for 2–3 hours, after which the material structure is assumed to be stabilized. This study shows that the consolidation process still continues at these temperatures after days to weeks. Ongoing condensation and structural evolution are studied in powders, films and gas permeation membranes derived from 1,2-bis(triethoxysilyl)ethane (BTESE) that are kept at temperatures up to 300 C for days and analyzed with in situ Fourier-transform infrared spectroscopy, 29Si cross-polarized magic angle spinning nuclear magnetic resonance, in situ spectroscopic ellipsometry, in situ gas permeation and in situ X-ray reflectivity. A continuously ongoing decrease in both silanol concentration and film thickness is observed, accompanied by changes in density, thermal expansion and micropore structure. The changes in the micropore structure are found to depend on pore size and affect the gas permeation performance of membranes. An important factor in the structural evolution is the network flexibility. Materials containing no organic bridges, short flexible bridges or long rigid bridges (derived from tetraethoxysilane (TEOS), bis(triethoxysilyl)methane (BTESM) and 1,4-bis(triethoxysilyl)benzene (BTESB), respectively) also show ongoing condensation, but their shrinkage rate is smaller as compared to BTESE-derived networks. A BTESE-derived film kept at 236 C for 12 days still shows no signs of approaching a structurally stabilized state.

KW - IR-103204

KW - METIS-320562

U2 - 10.1039/c6ta09559c

DO - 10.1039/c6ta09559c

M3 - Article

VL - 5

SP - 1268

EP - 1281

JO - Journal of materials chemistry. A

JF - Journal of materials chemistry. A

SN - 2050-7488

ER -