Data underlying the publication: Thermochromic Hydrogel with High Transmittance Modulation and Fast Response for Flexible Smart Windows

Growing environmental concerns are driving demand for energy-saving strategies. Thermochromic smart windows offer a practical solution by passively regulating sunlight in homes and offices. Despite recent progress, current technologies still face challenges in achieving the thermal durability and mechanical robustness necessary for long-term use, combined with a rapid transition below 30°C. Here we report a thermochromic hydrogel assembled from poly(N,N-dimethylaminoethyl methacrylate) and 2,2,2-trifluoroethyl methacrylate that produces flexible films on a large scale. This hydrogel rapidly (∆t ≈ 3 s) and reversibly becomes turbid above a tunable transition temperature spanning the human comfort zone, and maintains its thermochromic property even when mechanically stretched with 500% strain. The film’s high modulation of solar transmittance (70.6%) and luminous transmittance (85.7%) enables efficient sunlight screening in hot weather and clear vision in cool weather. Such ‘smart windows’ remain stable for over 10,000 heating/cooling cycles. These combined features indicate the hydrogel suitability for applications ranging from heat-modulating smart windows (architectural, automotive, etc.) to passive temperature indicators and even wearables.

日益凸显的环境问题正推动节能策略的市场需求持续增长。热致变色智能窗（thermochromic smart windows）可通过被动调节住宅与办公场所的日光入射，为节能需求提供切实可行的解决方案。尽管近期相关技术已取得一定进展，但现有方案仍难以兼顾长期使用所需的热耐久性与机械鲁棒性，以及30℃以下的快速相变响应性能。本研究报道了一种由聚(甲基丙烯酸N,N-二甲氨基乙酯)（poly(N,N-dimethylaminoethyl methacrylate)）与甲基丙烯酸2,2,2-三氟乙酯（2,2,2-trifluoroethyl methacrylate）共聚制备的热致变色水凝胶，可规模化制备柔性薄膜。该水凝胶在覆盖人体舒适区间的可调相变温度以上时，可在Δt≈3秒内快速发生可逆浊度变化；即便经受500%的机械拉伸，仍能保持热致变色性能。该薄膜对太阳能透过率的调制幅度达70.6%，可见光透过率达85.7%，可在炎热天气下高效阻隔日光，在凉爽天气下保证清晰视野。这类智能窗可经受超过10000次冷热循环而性能保持稳定。上述综合性能表明，该水凝胶可广泛应用于热调控智能窗（建筑、汽车等领域）、被动式温度指示器，乃至可穿戴设备等场景。