A Dual-Responsive Nanocomposite toward Climate-Adaptable Solar Modulation for Energy-Saving Smart Windows

Abstract

In this work, a novel fully autonomous photothermotropic material made by hybridization of the poly(N-isopropylacrylamide) (PNIPAM) hydrogel and antimony-tin oxide (ATO) is presented. In this photothermotropic system, the near-infrared (NIR)-absorbing ATO acts as nanoheater to induce the optical switching of the hydrogel. Such a new passive smart window is characterized by excellent NIR shielding, a photothermally activated switching mechanism, enhanced response speed, and solar modulation ability. Systems with 0, 5, 10, and 15 atom % Sb-doped ATO in PNIPAM were investigated, and it was found that a PNIPAM/ATO nanocomposite is able to be photothermally activated. The 10 atom % Sb-doped PNIPAM/ATO exhibits the best response speed and solar modulation ability. Different film thicknesses and ATO contents will affect the response rate and solar modulation ability. Structural stability tests at 15 cycles under continuous exposure to solar irradiation at 1 sun intensity demonstrated the performance stability of such a photothermotropic system. We conclude that such a novel photothermotropic hybrid can be used as a new generation of autonomous passive smart windows for climate-adaptable solar modulation.

PVB/ATO Nanocomposites for Glass Coating Applications: Effects of Nanoparticles on the PVB Matrix

“…To investigate how the content of ATO NPs affects the optical properties of the composites, we measured the UV-Vis-NIR transmittance of PVB loaded with both ATOu and ATOc NPs at filler fractions ranging from 0.5 to 5 wt %; the spectra are shown in Figure 10. The high shielding efficiency in the NIR region is due to ATO absorption [55] and has been previously observed for other nanocomposites containing ATO [12,14]. The transmittance in the visible region decreased with increased the ATO content and, at the same loading level, it was more pronounced for the composites containing ATOc compared to ATOu.…”

Preparation and Properties of Thermoresponsive P(N-Isopropylacrylamide-co-butylacrylate) Hydrogel Materials for Smart Windows

“…In the case of copolymers using comonomers, there have been reports of controlling LCST as a control of the hydrophilic and hydrophobic groups of monomers [23][24][25]. However, in these reports, the difference in light transmittance (ΔT) between light transmission and light interruption is relatively low, about 60%.…”

Spectrally Selective Smart Window with High Near-Infrared Light Shielding and Controllable Visible Light Transmittance

“…With photothermal materials, the heat in situ generated is proportional to the sunlight intensity and consequently the temperature can be modulated within a large range, typically from room temperature to even above 80 °C, [24][25][26][27][28][29] which greatly enhances the sensitivity and expand the library of candidate materials for smart windows. [10][11]16 Lighting room is an important functionality of many windows, which, instead of the entire solar spectrum, only the visible light contributes to. [30][31] The solar spectrum crosses UV, visible and NIR range, and the NIR part possesses more than 50% proportion of solar energy.…”