Hydrogel smart windows

Abstract

Smart windows are a promising way to modulate solar light transmittance, which is crucial for energy saving buildings. We provide an overview of the recent progress in hydrogel-based smart windows.

Liquid Thermo-Responsive Smart Window Derived from Hydrogel

“…The conventional thermo-responsive hydrogel is in the gel form and laminated between glasses to regulate the light transmittance solely. [56][57][58] The newly developed TRL experience a similar hydrophilic to hydrophobic transition at the lower critical solution temperature (LCST) as conventional hydrogel; below the LCST, the water molecules are within the PNIPAm macromolecules, which give high transparency, allowing the high solar transmission to heat the room in winter. Once heated above the LCST, the water molecules will be released from the PNIPAm, and the shrinkage particles will cause scattering of the light ( Figure 1C).…”

“…Once heated above the LCST, the water molecules will be released from the PNIPAm, and the shrinkage particles will cause scattering of the light ( Figure 1C). We would like to highlight that different from the in situ synthesis technique used for the production of conventional hydrogel, 55,58 the newly developed TRL is synthesized by dispersing PNIPAm particles into water and form the homogeneous solution, which gives it an advantage of free flowing. Although the current thermo-responsive hydrogel has been intensively investigated, [59][60][61][62][63] none of the work discusses the thermal capacity concept and none of them are free flow.…”

Hierarchical Network-Augmented Hydroglasses for Broadband Light Management

“…Most of the light management materials, such as the inorganic glasses doped with transition metal oxides, are brittle, easy to broken, and cannot repair the scratches [ 6 ]. Even for organic materials, including thermochromic elastomers, electrochromic liquid crystals, and nanostructured/microgel-reinforced hydrogels, they are also limited in stretchability and rarely self-healing [ 7 , 10 , 27 , 28 ]. In contrast, the HNAH window with the hierarchical networks ranging from nano- to micro-scale exhibits the advantages of the mechanical performance, which combines stretchability, self-healing, and notch-insensitivity.…”

Stimuli responsive dynamic transformations in supramolecular gels

“…[93][94][95][96] Photoresponsive gels are extensively used in cell culture and optoelectronics. [97][98][99][100] Fig. 4 (a) Chemical structure of the gelator studied by Xie et al 68 (b) Pictures of 2% hydrogel at pH = 5.37 at 25 1C and 50 1C together with its transmittance data during successive cooling-heating cycles.…”