Deformable Thermo-Responsive Smart Windows Based on a Shape Memory Polymer for Adaptive Solar Modulations

Abstract

Thermo-responsive smart windows that control solar transmission are expected to be the promising solution to excessive building energy consumption and overheating of solar cell devices. The two performance indices, namely, the luminous transmission (T lum ) and the solar modulation (ΔT sol ), are often intrinsically limited by conventional thermo-responsive materials, which restrict their applications in smart windows. Alternatively, constructing a deformable surface morphology of smart windows can be an effective strategy to modulate the solar transmission.Here, we report a new category of thermo-responsive smart windows with a deformable surface morphology, which can be custom designed to achieve both desirable ΔT sol and T lum according to the sunlight incident angles of actual applications. This design is based on a thermo-responsive shape memory polymer and an optical coating, which is termed the butterfly-wing-like smart window (BSW). The BSW reversibly transforms from a temporary shape of flat topography to a predefined original shape of tilted configuration upon heating. It is demonstrated that the BSW has a high ΔT sol of 32.6% and an excellent T lum(average) of 64.5%. This work provides a new design strategy and mechanism for thermo-responsive smart windows.

Recent advances in solar infrared light regulating smart windows based on organic materials

“…Other devices used deformable polyurethane coated with gold to act as a modifiable reflector, termed a “butterfly‐wing‐like smart window” (Figure 5). [36] While these two devices rely on metals to do the actual reflection, organic equivalents could be substituted in the future; for example, the nickel could theoretically be replaced by ChLC flakes [75] or the polyurethane coated with a reflective layer of ChLCs or cellulose nanocrystals [76] . See Table 1 for a summary of all the devices discussed in this section.…”

Review on Mechanoresponsive Smart Windows: Structures and Driving Modes

“…Building a deformable surface morphology of smart windows using thermo-responsive materials is an effective method to adjust the solar transmission. In Figure 9 a, Li et al used thermo-responsive shape memory polymer and the metal coating, displaying a butterfly wing-like smart window (BSW) [ 58 ]. Upon heating, this BSW enable the transition from a temporary flat shape to a predefined tilted configuration.…”

“… The strategy of thermal driving mode of mechanoresponsive smart windows: ( a ) formation of surface wrinkled structure [ 58 ] Copyright 2022, American Chemical Society, ( b ) formation of dynamic network structure [ 59 ] Copyright 2022, Royal Society Chemistry (London, UK), ( c ) formation of nanostripe structure [ 60 ] Copyright 2022, Elsevier, ( d ) formation of shape memory polymer grids [ 61 ], Copyright 2021, Springer Nature. …”

Dual manipulation of light and shape based on nanoparticle-induced shape memory composites

“…Inspired by the butterfly wings, micro-sized scales of thermos-responsive PU have the ability to modulate the solar transmission upon shape configuration. 20 However, these materials are fragile under environmental influences, such as friction, pressing, impact, etc. For the latter approach, Liu reports a liquid crystal elastomer-based actuator containing tetraarylsuccinonitrile chromophore via the thio-lene photoaddition method.…”