PDMS薄膜光谱调控及多层结构优化研究

Spectral Control and Multilayer Structure Optimization of PDMS Thin Films

摘要: 为明确聚二甲基硅氧烷(PDMS)薄膜厚度及复合层状结构对被动辐射冷却性能的影响规律，本文基于传输矩阵法构建一类薄膜光谱响应模型，结合AHP-熵权法综合评价体系和模拟退火–粒子群混合算法，系统探究PDMS基冷却薄膜的光谱调控特性与结构优化策略。结果表明：随膜厚增加，PDMS薄膜在8~13 μm大气窗口内的光谱发射率由明显干涉振荡逐渐趋于平稳，平均发射率先快速升高后趋于饱和，膜厚超过50 μm后性能增益显著减小。综合评价显示：30~50 μm为单层PDMS薄膜较优厚度区间，其中50 μm方案在冷却性能、材料消耗与工程制备可行性间平衡最佳。优化得到的Ag/SiO₂/PDMS复合结构，可通过金属反射层、介质调控层与聚合物发射层的协同作用，有效提升太阳波段反射能力并保持高红外发射能力，且具备一定工艺鲁棒性。这些研究可为PDMS基被动辐射冷却薄膜的设计与优化提供一定的理论参考。

Abstract: To clarify the influence of the thickness and composite layered structure of polydimethylsiloxane (PDMS) films on the passive radiation cooling performance, this paper constructed a film spectral response model based on the transfer matrix method, combined the AHP entropy weight method comprehensive evaluation system and simulated annealing particle swarm optimization method, and systematically explored the spectral control characteristics and structural optimization strategies of PDMS based cooling films. The results showed that as the film thickness increased, the spectral emissivity of PDMS thin films in the 8~13 μm atmospheric window could gradually stabilize from obvious interference oscillation, and the average emission first rapidly increased and then tended to saturation. At the same time, the performance gain significantly decreased after the film thickness exceeded 50 μm. The comprehensive evaluation shows that 30~50 μm was the optimal thickness range for single-layer PDMS films, with the 50 μm scheme achieving the best balance between cooling performance, material consumption, and engineering preparation feasibility. The optimized Ag/SiO₂/PDMS composite structure could effectively enhance the solar band reflection ability and maintain high infrared emission ability through the synergistic effect of the metal reflection layer, dielectric control layer, and polymer emission layer, and had certain process robustness. In summary, these studies could provide theoretical references for the design and optimization of passive radiative cooling films for PDMS.