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Achieving a mesoporous structure in superinsulation materials is pivotal for guaranteeing a harmonious relationship between low thermal conductivity, high porosity, and low density. Herein, we report silica-based cryogel and aerogel materials by implementing freeze-drying and ambient-pressure-drying processes respectively. The obtained freeze-dried cryogels yield thermal conductivity of 23 mW m −1 K −1 , with specific surface area of 369.4 m 2 g −1 , and porosity of 96.7%, whereas ambient-pressure-dried aerogels exhibit thermal conductivity of 23.6 mW m −1 K −1 , specific surface area of 473.8 m 2 g −1 , and porosity of 97.4%. In addition, the fiber-reinforced nanocomposites obtained via freeze-drying feature a low thermal conductivity (28.0 mW m −1 K −1 ) and high mechanical properties (∼620 kPa maximum compressive stress and Young's modulus of 715 kPa), coupled with advanced flame-retardant capabilities, while the composite materials from the ambient pressure drying process have thermal conductivity of 28.8 mW m −1 K −1 , ∼200 kPa maximum compressive stress and Young's modulus of 612 kPa respectively. The aforementioned results highlight the capabilities of both drying processes for the development of thermal insulation materials for energy-efficient applications.
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This content will become publicly available on March 21, 2026
Mechanically Strong and Photothermally Active Covalent Organic Framework Nanocomposite Aerogels for Applications in Gas Adsorption
Covalent organic framework (COF) aerogels arehierarchically porous polymeric materials with ultrahigh specific surface area, making them attractive for wide applications such as molecular capture, adsorption, and catalysis. Previous COF aerogel studies have focused on varying their chemical structures and linkage chemistries to fine-tune material properties and functionality, most of which have reported relatively unsatisfying performance (e.g., poor mechanical strength and strain tolerance). This study describes the synthesis and characterization of COF nanocomposite aerogels, whose material properties and functionality are effectively engineered through the incorporation of reinforcing fillers/binders or functional additives. Boron nitride (BN) fillers, cross-linked poly(acrylic acid) (XPAA) binders, and gold nanoparticles (AuNps) are incorporated into 1,3,5-tris(aminophenyl)benzene-terephthaldehyde (TAPB-PDA) COF aerogel matrices to form homogeneous nanocomposite aerogels with enhanced mechanical properties and unique photothermal conversion capabilities. Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy results confirm the successful filler/additive inclusion into the final COF nanocomposite aerogels. Specifically, BN filler loading at ∼17 wt % relative to final COF mass doubles COF aerogel’s Young’s modulus from 11 to 22 kPa according to mechanical compression tests, with only ∼10% reduction in COF’s accessible mesopores’ surface area according to nitrogen porosimeter analyses. Meanwhile, incorporating ∼7 wt % XPAA relative to final COF mass improves the Young’s modulus to 21 kPa, while increasing the aerogel’s yield strain from 10 to 65% strain, although this leads to a ∼35% reduction in COF’s accessible mesopores’ surface area. Furthermore, photothermal AuNps are incorporated to form functional COF nanocomposite aerogels, whose overall temperature increases by 5.5 °C after 1 sun (AM1.5G, 1000 W m−2) irradiation. Overall, this study demonstrates potential routes to fabricate hierarchically porous COF nanocomposite aerogels with high specific surface area, robust mechanical stability, and unique photothermal functionality, which hold promises for applications in adsorption separation, gas storage, and photocatalysis.
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- Award ID(s):
- 2216843
- PAR ID:
- 10614042
- Editor(s):
- Bowden, Ned
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- ACS Applied Nano Materials
- Volume:
- 8
- Issue:
- 11
- ISSN:
- 2574-0970
- Page Range / eLocation ID:
- 5815 to 5828
- Subject(s) / Keyword(s):
- covalent organic framework (COF), aerogel, composites, hierarchically porous, high surface area, mechanically strong, photothermal, adsorption
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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