Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings
Abstract With the mandate of worldwide carbon neutralization, pursuing comfortable living environment while consuming less energy is an enticing and unavoidable choice. Novel composite aerogels with super thermal insulation and high sunlight reflection are developed for energy-efficient buildings. A...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-02-01
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| Series: | Nano-Micro Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s40820-022-00797-6 |
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| author | Jie Yang Kit-Ying Chan Harun Venkatesan Eunyoung Kim Miracle Hope Adegun Jeng-Hun Lee Xi Shen Jang‐Kyo Kim |
| author_facet | Jie Yang Kit-Ying Chan Harun Venkatesan Eunyoung Kim Miracle Hope Adegun Jeng-Hun Lee Xi Shen Jang‐Kyo Kim |
| author_sort | Jie Yang |
| collection | DOAJ |
| description | Abstract With the mandate of worldwide carbon neutralization, pursuing comfortable living environment while consuming less energy is an enticing and unavoidable choice. Novel composite aerogels with super thermal insulation and high sunlight reflection are developed for energy-efficient buildings. A solvent-assisted freeze-casting strategy is used to produce boron nitride nanosheet/polyvinyl alcohol (BNNS/PVA) composite aerogels with a tailored alignment channel structure. The effects of acetone and BNNS fillers on microstructures and multifunctional properties of aerogels are investigated. The acetone in the PVA suspension enlarges the cell walls to suppress the shrinkage, giving rise to a lower density and a higher porosity, accompanied with much diminished heat conduction throughout the whole product. The addition of BNNS fillers creates whiskers in place of disconnected transverse ligaments between adjacent cell walls, further ameliorating the thermal insulation transverse to the cell wall direction. The resultant BNNS/PVA aerogel delivers an ultralow thermal conductivity of 23.5 mW m−1 K−1 in the transverse direction. The superinsulating aerogel presents both an infrared stealthy capability and a high solar reflectance of 93.8% over the whole sunlight wavelength, far outperforming commercial expanded polystyrene foams with reflective coatings. The anisotropic BNNS/PVA composite aerogel presents great potential for application in energy-saving buildings. |
| first_indexed | 2024-04-11T17:52:53Z |
| format | Article |
| id | doaj.art-271c44c61e1741d89b7fb5adbf37b2ab |
| institution | Directory Open Access Journal |
| issn | 2311-6706 2150-5551 |
| language | English |
| last_indexed | 2024-04-11T17:52:53Z |
| publishDate | 2022-02-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Nano-Micro Letters |
| spelling | doaj.art-271c44c61e1741d89b7fb5adbf37b2ab2022-12-22T04:11:00ZengSpringerOpenNano-Micro Letters2311-67062150-55512022-02-0114111610.1007/s40820-022-00797-6Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient BuildingsJie Yang0Kit-Ying Chan1Harun Venkatesan2Eunyoung Kim3Miracle Hope Adegun4Jeng-Hun Lee5Xi Shen6Jang‐Kyo Kim7Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyAbstract With the mandate of worldwide carbon neutralization, pursuing comfortable living environment while consuming less energy is an enticing and unavoidable choice. Novel composite aerogels with super thermal insulation and high sunlight reflection are developed for energy-efficient buildings. A solvent-assisted freeze-casting strategy is used to produce boron nitride nanosheet/polyvinyl alcohol (BNNS/PVA) composite aerogels with a tailored alignment channel structure. The effects of acetone and BNNS fillers on microstructures and multifunctional properties of aerogels are investigated. The acetone in the PVA suspension enlarges the cell walls to suppress the shrinkage, giving rise to a lower density and a higher porosity, accompanied with much diminished heat conduction throughout the whole product. The addition of BNNS fillers creates whiskers in place of disconnected transverse ligaments between adjacent cell walls, further ameliorating the thermal insulation transverse to the cell wall direction. The resultant BNNS/PVA aerogel delivers an ultralow thermal conductivity of 23.5 mW m−1 K−1 in the transverse direction. The superinsulating aerogel presents both an infrared stealthy capability and a high solar reflectance of 93.8% over the whole sunlight wavelength, far outperforming commercial expanded polystyrene foams with reflective coatings. The anisotropic BNNS/PVA composite aerogel presents great potential for application in energy-saving buildings.https://doi.org/10.1007/s40820-022-00797-6Boron nitride nanosheetsSolvent-assisted freeze-castingThermally insulating aerogelSolar reflectanceEnergy-saving buildings |
| spellingShingle | Jie Yang Kit-Ying Chan Harun Venkatesan Eunyoung Kim Miracle Hope Adegun Jeng-Hun Lee Xi Shen Jang‐Kyo Kim Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings Nano-Micro Letters Boron nitride nanosheets Solvent-assisted freeze-casting Thermally insulating aerogel Solar reflectance Energy-saving buildings |
| title | Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings |
| title_full | Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings |
| title_fullStr | Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings |
| title_full_unstemmed | Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings |
| title_short | Superinsulating BNNS/PVA Composite Aerogels with High Solar Reflectance for Energy-Efficient Buildings |
| title_sort | superinsulating bnns pva composite aerogels with high solar reflectance for energy efficient buildings |
| topic | Boron nitride nanosheets Solvent-assisted freeze-casting Thermally insulating aerogel Solar reflectance Energy-saving buildings |
| url | https://doi.org/10.1007/s40820-022-00797-6 |
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