串珠结构PVDF/SiO_(2)纳米纤维膜的构建及日间辐射制冷性能

Construction of beaded PVDF/SiO_(2) nanofiber film and its daytime radiation cooling performance

日间辐射制冷材料因不需要能源输入,仅依靠大气窗口便可将热量发送到外太空实现降温,在房屋遮盖物、车罩、降温服饰等领域显示优异的应用潜力。试验选择红外高发射的聚偏氟乙烯(PVDF)和二氧化硅(SiO_(2))球作为高发射基质材料,利用静电纺丝方法构建具有串珠结构的PVDF/SiO_(2)纳米纤维膜。相较常规的纤维结构,串珠结构PVDF/SiO_(2)纳米纤维膜中纤维直径分布较宽,可提高Mie散射强度,且粒子的掺杂增加了光的散射次数,使得太阳光反射率高达97.15%;同时,PVDF和SiO_(2)固有的红外高吸收性能可赋予纤维膜高达97.80%的中红外发射率,呈现优异的日间辐射制冷性能。在太阳光照射下,PVDF/SiO_(2)纳米纤维膜表面温度显著低于环境和其他纺织品的表面温度,并在人体热管理和物体降温方面表现出优异的应用能力。

Daytime radiative cooling materials show excellent application potential in the fields of house cover,car cover and cooling clothing because it can send heat to outer space for cooling through atmospheric win⁃dow without needing energy input.Polyvinylidene fluoride(PVDF)and silicon dioxide(SiO_(2))spheres with high infrared emission are selected as high emission matrix materials,PVDF/SiO_(2) nanofiber film with beaded fiber structure is constructed by electrospinning.Compared with conventional fiber structure,the fiber diameter of beaded PVDF/SiO_(2) nanofiber film distributes in a wide range,which increases the Mie scattering intensity.Al⁃so,the doped SiO_(2) can increase the number of sunlight scattering,making the reflectivity of sunlight as high as 97.15%.Moreover,the inherent infrared absorption of PVDF and SiO_(2) also gives the film an excellent mid-infra⁃red emissivity of up to 97.80%,endowing perfect daytime radiation cooling performance.Under the direct expo⁃sure of sunlight,the surface temperature of the beaded PVDF/SiO_(2) nanofiber film is significantly lower than that of the environment and other textiles,showing excellent application ability in personal thermal manage⁃ment and object cooling.