Abstract
Thermochromic hydrogels are versatile smart materials that have many applications, including in smart windows, sensing, camouflage, etc. The previous reports of hydrogel smart windows have been based on covalent crosslinking, requiring multistep processing, and complicated preparation. Moreover, most research studies focused on enhancing the luminous transmittance (Tlum) and modulating ability (ΔTsol), while the structural integrity and antifreezing ability, which are essential in practical applications, have been compromised and rarely investigated. Herein, we develop a new physical (noncovalent crosslinked) hydrogel-derived smart window by introducing an in situ free radical polymerization (FRP) of N-isopropylacrylamide (NIPAM) in a glycerol-water (GW) binary solvent system. The noncovalent crosslinked PNIPAM GW solutions are facilely synthesized, giving outstanding freezing tolerance (∼−18 °C), a comparably high Tlum of 90%, and ΔTsol of 60.8%, together with added advantages of fast response time (∼10 s) and good structural integrity before and after phase transition. This work could provide a new strategy to design and fabricate heat stimulated smart hydrogels not limited to energy saving smart windows.
| Original language | English |
|---|---|
| Pages (from-to) | 2004-2012 |
| Number of pages | 9 |
| Journal | Materials Horizons |
| Volume | 10 |
| Issue number | 6 |
| Early online date | 23 Mar 2023 |
| DOIs | |
| Publication status | Published - 23 Jun 2023 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 The Royal Society of Chemistry.
Funding
This work was supported by the National Natural Science Foundation of China (No. 51573144 and 51521001), the Innovation Team in Key Areas of the Innovation Talent Promotion Plan (2021) of MOST, China, and the China Scholarship Council (CSC20200695030). Y. Long is thankful for the funding support from the Ministry of Education Singapore Tier 1 RG71/21, Global STEM Professorship Scheme sponsored by the Government of the Hong Kong Special Administrative Region.