Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 1268-1281 |
| Number of pages | 14 |
| Journal | Journal of materials chemistry. A |
| Volume | 5 |
| DOIs | |
| Publication status | Published - 2017 |
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Keywords
- IR-103204
- METIS-320562
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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 journal › Article › Academic › peer-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 -