Nowadays, passive radiative cooling (PRC) has being attracted intensive attention because it can realize cooling effect without consuming any energy. Unfortunately, fabricating polymer film with radiative cooling effect by a facile, continuous and environmentally friendly method is still a large challenge. In this study, high density polyethylene (HDPE)/polyvinyl oxide (PEO) film were first fabricated by melt extrusion casting method, and polyethylene film composed of directional microfibrils (PFCDM) were finally obtained after selective dissolution of PEO phase in deionized water at 70 °C. The as-prepared PFCDM shows higher average solar reflectivity of 85.17% in the visible range and stronger average mid-infrared emissivity of 82.04% within the atmospheric window. It shows a sub-ambient cooling of 23.28 °C during the day and 3.1 °C at night, suggesting that it has a remarkable PRC performance. Moreover, the as-prepared PFCDM has outstanding wearability and self-cleaning property, showing promising potential of personal thermal management. This study proposes a facile but environmentally friendly method for fabricating PFCDM, paving a new way to develop wearable PRC film following the concept of thermoplastic polymers “functionalized” processing.

中文翻译：

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由定向微纤维组成的易于制造的聚乙烯薄膜，用于被动辐射冷却

如今，被动辐射冷却（PRC）因其无需消耗任何能源即可实现冷却效果而受到广泛关注。不幸的是，通过简便、连续且环保的方法制造具有辐射冷却效果的聚合物薄膜仍然是一个巨大的挑战。本研究首先采用熔融挤出流延法制备高密度聚乙烯（HDPE）/聚氧化乙烯（PEO）薄膜，并在70℃的去离子水中选择性溶解PEO相，最终得到定向微纤丝组成的聚乙烯薄膜（PFCDM）。 °C。所制备的 PFCDM 在可见光范围内表现出较高的平均太阳反射率（85.17%），在大气窗口内表现出较强的平均中红外发射率（82.04%）。它显示白天的低于环境温度为 23.28 °C，夜间为 3.1 °C，表明其具有出色的 PRC 性能。此外，所制备的PFCDM具有出色的耐磨性和自清洁性能，在个人热管理方面显示出良好的潜力。这项研究提出了一种简便但环保的 PFCDM 制造方法，为遵循热塑性聚合物“功能化”加工概念开发可穿戴 PRC 薄膜开辟了新途径。