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- Publisher Website: 10.1021/acsami.1c03803
- Scopus: eid_2-s2.0-85106367123
- PMID: 33969687
- WOS: WOS:000655027500039
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Article: Self-Densified Optically Transparent VO2 Thermochromic Wood Film for Smart Windows
Title | Self-Densified Optically Transparent VO2 Thermochromic Wood Film for Smart Windows |
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Authors | |
Keywords | energy-efficient glazing thermochromic smart windows transparent wood thermal management vanadium dioxide |
Issue Date | 2021 |
Publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/journal/aamick |
Citation | ACS Applied Materials & Interfaces, 2021, v. 13 n. 19, p. 22495-22504 How to Cite? |
Abstract | Optically transparent wood has emerged as a promising glazing material. Thanks to the high optical transmittance, strong mechanical properties, and excellent thermal insulation capability of transparent wood, it offers a potential alternative to glass for window applications. Recently, thermo-, electro-, and photochromic transparent woods that dynamically modulate light transmittance have been investigated to improve building energy efficiency. However, it remains challenging to widely replace windows with transparent wood because of its poor weather resistance. In this study, an environment-friendly thermochromic transparent wood film (TTWF) with thermal switching of transmittance is proposed and demonstrated. To achieve thermochromism, the bleached wood is impregnated with the vanadium dioxide (VO2)/polyvinyl alcohol composite. Due to the self-densification of cellulose microfibrils during the evaporation of solvents, the transparent wood is in the form of thin films, which can be attached on the inner face of a window to protect it from severe weather conditions, making the installation convenient and low-cost. Furthermore, the surface of VO2-TTWF is modified by octadecyltrichlorosilane to enhance the waterproof ability and achieve self-cleaning and antidust functions. The proposed VO2-TTWF shows great potential for application in energy-efficient buildings using sustainable materials with advanced optical properties (i.e., Tlum = 50.5%, ΔTsol = 3.4%, and haze = 70%) that are mechanically robust (i.e., σ = 130.6 MPa along the wood growth direction), have low-thermal conductivity (i.e., K = 0.29 W m–1 K–1 along the perpendicular direction to the wood fibers), and demonstrate hydrophobic self-cleaning and antidust functions (i.e., contact angle: 121.9°). An experiment, using a model house, showed that the VO2-TTWF attached on the inner face of the window could significantly reduce the indoor air temperature by 33.9 °C compared with a bare glass panel, proving that VO2-TTWF has potential to be applied as a new-generation energy-efficient material for smart windows. |
Persistent Identifier | http://hdl.handle.net/10722/305832 |
ISSN | 2021 Impact Factor: 10.383 2020 SCImago Journal Rankings: 2.535 |
ISI Accession Number ID |
DC Field | Value | Language |
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dc.contributor.author | Liu, S | - |
dc.contributor.author | Tso, CY | - |
dc.contributor.author | Lee, HH | - |
dc.contributor.author | Du, YW | - |
dc.contributor.author | Yu, KM | - |
dc.contributor.author | Feng, SP | - |
dc.contributor.author | Huang, B | - |
dc.date.accessioned | 2021-10-20T10:14:57Z | - |
dc.date.available | 2021-10-20T10:14:57Z | - |
dc.date.issued | 2021 | - |
dc.identifier.citation | ACS Applied Materials & Interfaces, 2021, v. 13 n. 19, p. 22495-22504 | - |
dc.identifier.issn | 1944-8244 | - |
dc.identifier.uri | http://hdl.handle.net/10722/305832 | - |
dc.description.abstract | Optically transparent wood has emerged as a promising glazing material. Thanks to the high optical transmittance, strong mechanical properties, and excellent thermal insulation capability of transparent wood, it offers a potential alternative to glass for window applications. Recently, thermo-, electro-, and photochromic transparent woods that dynamically modulate light transmittance have been investigated to improve building energy efficiency. However, it remains challenging to widely replace windows with transparent wood because of its poor weather resistance. In this study, an environment-friendly thermochromic transparent wood film (TTWF) with thermal switching of transmittance is proposed and demonstrated. To achieve thermochromism, the bleached wood is impregnated with the vanadium dioxide (VO2)/polyvinyl alcohol composite. Due to the self-densification of cellulose microfibrils during the evaporation of solvents, the transparent wood is in the form of thin films, which can be attached on the inner face of a window to protect it from severe weather conditions, making the installation convenient and low-cost. Furthermore, the surface of VO2-TTWF is modified by octadecyltrichlorosilane to enhance the waterproof ability and achieve self-cleaning and antidust functions. The proposed VO2-TTWF shows great potential for application in energy-efficient buildings using sustainable materials with advanced optical properties (i.e., Tlum = 50.5%, ΔTsol = 3.4%, and haze = 70%) that are mechanically robust (i.e., σ = 130.6 MPa along the wood growth direction), have low-thermal conductivity (i.e., K = 0.29 W m–1 K–1 along the perpendicular direction to the wood fibers), and demonstrate hydrophobic self-cleaning and antidust functions (i.e., contact angle: 121.9°). An experiment, using a model house, showed that the VO2-TTWF attached on the inner face of the window could significantly reduce the indoor air temperature by 33.9 °C compared with a bare glass panel, proving that VO2-TTWF has potential to be applied as a new-generation energy-efficient material for smart windows. | - |
dc.language | eng | - |
dc.publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/journal/aamick | - |
dc.relation.ispartof | ACS Applied Materials & Interfaces | - |
dc.rights | This document is the Accepted Manuscript version of a Published Work that appeared in final form in [JournalTitle], copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [insert ACS Articles on Request author-directed link to Published Work, see http://pubs.acs.org/page/policy/articlesonrequest/index.html]. | - |
dc.subject | energy-efficient glazing | - |
dc.subject | thermochromic smart windows | - |
dc.subject | transparent wood | - |
dc.subject | thermal management | - |
dc.subject | vanadium dioxide | - |
dc.title | Self-Densified Optically Transparent VO2 Thermochromic Wood Film for Smart Windows | - |
dc.type | Article | - |
dc.identifier.email | Feng, SP: hpfeng@hku.hk | - |
dc.identifier.authority | Feng, SP=rp01533 | - |
dc.description.nature | link_to_subscribed_fulltext | - |
dc.identifier.doi | 10.1021/acsami.1c03803 | - |
dc.identifier.pmid | 33969687 | - |
dc.identifier.scopus | eid_2-s2.0-85106367123 | - |
dc.identifier.hkuros | 327709 | - |
dc.identifier.volume | 13 | - |
dc.identifier.issue | 19 | - |
dc.identifier.spage | 22495 | - |
dc.identifier.epage | 22504 | - |
dc.identifier.isi | WOS:000655027500039 | - |
dc.publisher.place | United States | - |