Abstract Many phase change materials (PCMs) experience a change in transparency when undergoing a phase transition. These thermo-optically responsive materials can be used to generate passive temperature control systems for building enclosures. The integration of optical and thermal switches into smart temperature-controlling elements requires rationally designed PCMs featuring tunable optical and thermal properties. Two polymers, poly (Octadecyl methacrylate) (PSMA) and poly(2-(2-(octadecyloxy) ethoxy) ethyl methacrylate) (PE2SMA) were synthesized and evaluated for their potential use in passive thermal energy storage systems. UV–Visible Spectroscopy, Near Infra-Red Spectroscopy, and Differential Scanning Calorimetry were used to evaluate the effect that changes in the polymer chemical structure had on the optical and thermal properties of the resulting materials. Insertion of a 6-atom flexible spacer (diethylene glycol) between the pendant crystalline motif and the polymer backbone of PSMA resulted in increases of latent heat storage capacity from 62 J/g to 94 J/g and thermal conductivity from 0.218 W/mK to 0.318 W/mK. Notably, insertion of a flexible spacer also resulted in a melting transition temperature increase from 37.7 °C for PSMA to 48 °C for PE2SMA. The visible transmittance of the polymers increased from 0% to 90% upon transition from crystalline to amorphous state. This study presents a synthetic strategy to control thermal and optical properties of polymeric PCMs materials. The material properties and structure-property relationships derived from this study will enable the refinement of the models used to predict the performance of passive temperature-regulating systems. More accurate models will guide the development of the thermo-responsive polymeric materials required for better perfoming temperature-regulating building enclosures.

中文翻译：

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用于被动温度调节的热光响应相变材料

摘要 许多相变材料 (PCM) 在经历相变时会经历透明度的变化。这些热光响应材料可用于生成用于建筑外壳的被动温度控制系统。将光学和热开关集成到智能温度控制元件中需要合理设计的具有可调光学和热特性的 PCM。合成了两种聚合物，聚（甲基丙烯酸十八烷基酯）（PSMA）和聚（2-（2-（十八烷基氧基）乙氧基）甲基丙烯酸乙酯）（PE2SMA），并评估了它们在被动热能储存系统中的潜在用途。紫外-可见光谱、近红外光谱、和差示扫描量热法用于评估聚合物化学结构的变化对所得材料的光学和热性能的影响。在悬垂结晶基序和 PSMA 聚合物骨架之间插入 6 原子柔性间隔物（二甘醇）导致潜热储存容量从 62 J/g 增加到 94 J/g，热导率从 0.218 W/mK 增加到0.318 W/mK。值得注意的是，插入柔性垫片还导致熔化转变温度从 PSMA 的 37.7 °C 增加到 PE2SMA 的 48 °C。聚合物从结晶态转变为非晶态时，其可见光透射率从 0% 增加到 90%。本研究提出了一种控制聚合物 PCM 材料的热学和光学性能的合成策略。从这项研究中得出的材料特性和结构-特性关系将有助于改进用于预测被动温度调节系统性能的模型。更准确的模型将指导开发更好的温度调节建筑围护结构所需的热响应聚合物材料。