Reducing the amount of electricity used by cooling systems is essential for lowering CO₂ emissions; therefore suppressing increases in room temperature in an environmentally friendly manner requires the development of heat-shielding materials that autonomously control sunlight without the use of electricity. Hydroxypropyl cellulose (HPC) has attracted attention as a lower critical solution temperature (LCST) type of temperature-responsive polymer. HPC is a thermochromic material that changes its optical properties in response to changes in external temperature. In this study, acrylamide (AAm) and HPC with various molecular weights were used to prepare HPC-AAm hydrogels, and their optical, heat-shielding, and weathering-resistant properties were evaluated. UV–vis–NIR spectroscopy revealed that the solar transmittance (αT_sol) of the HPC-AAm hydrogel decreased while its solar reflectance (αR_sol) increased with increasing HPC concentration above LCST. The αT_sol of low-molecular-weight HPC was found to be lower than that of high-molecular-weight HPC. In addition, the temperature inside a box constructed using an HPC-AAm hydrogel window was approximately 10 °C lower than that constructed using glass alone. Furthermore, the optical properties of the HPC-AAm hydrogel were found to hardly deteriorated even when continuously exposed to heat and UV radiation for 150 h. Therefore, the HPC-AAm hydrogel prepared in this study is expected to be useful as a heat-shielding material.

减少冷却系统使用的电量对于降低 CO ₂至关重要排放量；因此，以环境友好的方式抑制室温升高需要开发隔热材料，该材料可以在不使用电力的情况下自主控制阳光。羟丙基纤维素 (HPC) 作为一种较低临界溶解温度 (LCST) 类型的温度响应聚合物已引起关注。HPC 是一种热致变色材料，可根据外部温度的变化改变其光学特性。在本研究中，使用不同分子量的丙烯酰胺（AAm）和 HPC 制备 HPC-AAm 水凝胶，并对其光学、隔热和耐候性能进行了评估。紫外-可见-近红外光谱表明，太阳光透射率（αT _sol) 的 HPC-AAm 水凝胶降低，而其太阳反射率 ( αR _sol ) 随着 HPC 浓度的增加而增加，高于 LCST。发现低分子量 HPC的αT_溶胶低于高分子量 HPC。此外，使用 HPC-AAm 水凝胶窗口构建的盒子内的温度比单独使用玻璃构建的盒子内的温度低约 10°C。此外，发现 HPC-AAm 水凝胶的光学性能即使在持续暴露于热和紫外线辐射下 150 小时也几乎不会恶化。因此，本研究中制备的 HPC-AAm 水凝胶有望用作隔热材料。