Unusual flexibility of transparent poly(methylsilsesquioxane) aerogels by surfactant-induced mesoscopic fiber-like assembly

ガラスのように透明で曲げられるエアロゲル --高性能透明断熱材として期待--. 京都大学プレスリリース. 2024-01-19.High-performance thermal insulators represented by aerogels are regarded as one of the most promising materials for energy savings. However, significantly low mechanical strength has been a barrier for aerogels to be utilized in various social domains such as houses, buildings, and industrial plants. Here, we report a synthetic strategy to realize highly transparent aerogels with unusually high bending flexibility based on poly(methylsilsesquioxane) (PMSQ) network. We have constructed mesoscopic fine fiber-like structures of various sizes in PMSQ gels by the combination of phase separation suppression by tetramethylammonium hydroxide (TMAOH) and mesoscopic fiber-like assembly by nonionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-b-PPO-b-PEO) type surfactant. The optimized mesoscale structures of PMSQ gels have realized highly transparent and resilient monolithic aerogels with much high bendability compared to those reported in previous works. This work will provide a way to highly insulating materials with glasslike transparency and high mechanical flexibility

Formulation of metal-organic framework inks for the 3D printing of robust microporous solids

International audienceMetal-organic frameworks (MOFs) are a fast-growing class of highly porous materials owing to their exceptional structural diversity. A consequent effort has been deployed during the past few years for rationalizing the preparation of the most promising MOF structures, in view of their applications at larger scale. Still, their shaping represents a major bottleneck due to the difficulty to conciliate high porosity and adequate mechanical resistance to withstand overtime damaging stresses.3D printing is a promising technology as it allows the fast prototyping of materials at the macroscale.1 Herein, a 3D printer was modified to prepare a variety of MOF-based solids with controlled morphology from shear-thinning inks containing a cellulose-derived binder. Four benchmark MOFs were tested: HKUST-1, CPL-1, ZIF-8 and UiO-66-NH2. All solids are mechanically stable up to 0.6 MPa of uniaxial compression and highly porous, with BET specific surface areas lowered by 0 to -25%. Furthermore, these solids were applied to high pressure sorption (CH4, C2H4 and C2H6) and presented performances in line with the literature

Formulation of Metal–Organic Framework Inks for the 3D Printing of Robust Microporous Solids toward High-Pressure Gas Storage and Separation

International audienceThe shaping of metal−organic frameworks (MOFs) has become increasingly studied over the past few years, because it represents a major bottleneck toward their further applications at a larger scale. MOF-based macroscale solids should present performances similar to those of their powder counterparts, along with adequate mechanical resistance. Three-dimensional printing is a promising technology as it allows the fast prototyping of materials at the macroscale level; however, the large amounts of added binders have a detrimental effect on the porous properties of the solids. Herein, a 3D printer was modified to prepare a variety of MOF-based solids with controlled morphologies from shear-thinning inks containing 2-hydroxyethyl cellulose. Four benchmark MOFs were tested for this purpose: HKUST-1, CPL-1, ZIF-8, and UiO-66-NH 2. All solids are mechanically stable with up to 0.6 MPa of uniaxial compression and highly porous with BET specific surface areas lowered by 0 to −25%. Furthermore, these solids were applied to high-pressure hydrocarbon sorption (CH 4 , C 2 H 4 , and C 2 H 6), for which they presented a consequent methane gravimetric uptake (UiO-66-NH 2 , ZIF-8, and HKUST-1) and a highly preferential adsorption of ethylene over ethane (CPL-1)

Unusual Flexibility of Transparent Poly(methylsilsesquioxane) Aerogels by Surfactant-Induced Mesoscopic Fiber Assembly

We report a new synthetic strategy to realize highly transparent aerogels with outstanding bending flexibility. Taking poly(methylsilsesquioxane) (PMSQ) aerogels as an example, surfactant-induced fiber-like mesoscopic assembly of PMSQ and poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-b-PPO-b-PEO, so-called Pluronics) has been demonstrated. The obtained PMSQ aerogels possessed a characteristic branched fibrous structure in the mesoscale. With employing various kinds of PEO-b-PPO-b-PEO as the structure determining agent, optimization of the mesoscale structure of PMSQ gels has realized highly transparent aerogels with outstanding bendability compared to those reported in previous works. This approach provides a novel way to thermally superinsulating flexible devices with glasslike transparency

Unusual flexibility of transparent poly(methylsilsesquioxane) aerogels by surfactant-induced mesoscopic fiber-like assembly

High-performance thermal insulators represented by aerogels are regarded as one of the most promising materials for energy savings. However, significantly low mechanical strength has been a barrier for aerogels to be utilized in various social domains such as houses, buildings, and industrial plants. Here, we report a synthetic strategy to realize highly transparent aerogels with unusually high bending flexibility based on poly(methylsilsesquioxane) (PMSQ) network. We have constructed mesoscopic fine fiber-like structures of various sizes in PMSQ gels by the combination of phase separation suppression by tetramethylammonium hydroxide (TMAOH) and mesoscopic fiber-like assembly by nonionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-b-PPO-b-PEO) type surfactant. The optimized mesoscale structures of PMSQ gels have realized highly transparent and resilient monolithic aerogels with much high bendability compared to those reported in previous works. This work will provide a way to highly insulating materials with glasslike transparency and high mechanical flexibility.ガラスのように透明で曲げられるエアロゲル --高性能透明断熱材として期待--. 京都大学プレスリリース. 2024-01-19