Robust Solvatochromic Gels for Self-defensive Smart Windows

Smart materials that can dynamically modulate incident light provide a broad prospect for the development of smart windows. However, the absence of capability to create smart materials with rapid transmittance switchability and mechanical robustness has restricted the realization of self-defensive smart windows. Here, a solvatochromic alcogel designed by cellulose-polyacrylamide supramolecular configuration for developing a self-defensive smart window is reported. The alcogel with compact nano-bulge structures exhibits reversible and rapid switching of transparency between 85% and 5%, cycle time less than 8 s, and has strong mechanical robustness with elastic modulus of over 60 MPa. With this smart alcogel, the proposed self-defensive smart window not only shows real-time and reliable adjustment of transparency but also outputs a strong mechanical impact resistance of up to 42.8 kJ m(-2), 10 and 12 times higher than that of a normal glass and photochromic window, respectively. It is believed that this study will open new opportunities for both fabrication and application of biological gels in smart windows and intelligent devices.