Thermo-responsive smart glass based on an eco-friendly aqueous solution

About 40% of global energy is used in buildings, with windows being one of the least energy-efficient components. Smart glass has shown promise in reducing energy consumption and improving building comfort. In this work, we report a novel smart glass utilizing an eco-friendly aqueous solution of a non-ionic surfactant (1 wt% Triton CF-32 in water), offering dual-mode optical modulation via thermally induced phase separation. Importantly, the non-ionic surfactant used is a well-established commercial product with exceptionally low cost. Its adoption obviates the need for developing new material synthesis routes or establishing additional production lines. The aqueous solution is encapsulated in ITO-coated glass cells, exhibiting a sharp transition from a transparent to a turbid state near its cloud point. This reversible clouding effect can be triggered either passively (sunlight) or actively (Joule heating under applied voltage), enabling robust and energy-efficient switching behavior. In active mode, the transparency of the glass can be electrically controlled by the application of different voltages. This voltage-driven modulation enables significant control over the optical properties of the device. The system exhibits excellent thermo-responsive optical performance, with a luminous transmittance of approximately 77%, a haze of about 90%, and a solar modulation efficiency of around 64%. The proposed smart glass, fabricated from a biocompatible aqueous solution, offers an environmentally sustainable approach while achieving excellent energy conservation performance.