Construction and thermal conductivity of PVDF/Ag fiber membranes with high thermal conductivity
Conventional textiles cannot effectively dissipate heat in frequently high temperature weather caused by global warming,so they cannot meet the needs of people or objects for thermal regulation.Textiles with thermal conductivity have received extensive attention because they can transfer the heat of the human body or objects directly to the external environment for realizing heat regulation through heat conduction in a simple and fast way.Based on this,textiles with thermal conductivity are widely developed through various methods such as fiber blending,coating,and filling.However,there still exist many limitations of complicated preparation process,easy shedding and uneven distribution of materials with thermal conductivity,and insufficient improvement of thermal conductivity.To improve the thermal conductivity of fiber materials,we,starting from fine structure regulation of thermal conductivity networks,selected polyvinylidene fluoride(PVDF)and Ag flakes with different scales as the substrate and thermal conductivity filler,designed the connecting structures of mix-scaled Ag sheets in the fiber membrane,and used electrospinning technology to construct a PVDF/Ag fiber membrane with a three-dimensional interconnected thermal conductivity network in one step.The morphologies and chemical structures of the PVDF/Ag fiber membrane were characterized by field emission scanning electron microscope with EDS spectrometer and X-ray photoelectron spectroscopy.The distribution and formed network structure of mix-scaled Ag flakes in the fiber were analyzed through morphology observation.The water contact angle and mechanical properties of the fiber membrane were recorded by droplet contact angle measuring instrument and strength testing instrument,respectively.The thermal conductivity and mechanism of PVDF/Ag fiber films with different Ag flake sizes,Ag flake contents,and compression degrees were researched by using a thermal conductivity meter.Finally,the practical application on thermal conductivity of PVDF/Ag fiber membranes before and after compression was tested through a heating table and temperature by measuring instruments.The results show that the addition of mixed-size Ag flakes can form a three-dimensional network structure with internal connectivity of a single fiber and external connectivity between fibers and their connectivity between fibers gradually enhances with the content increase of large-sized Ag flakes.When the Ag content is four times that of PVDF polymer,the PVDF/Ag fiber membrane with a three-dimensional interconnected network structure exhibits excellent thermal conductivity,with a thermal conductivity coefficient of 0.1038 W/(mK),which is 61％higher than that of pure PVDF fiber membranes.After compression treatment,the thermal conductivity of the PVDF/Ag fiber membrane increases to 8.693 W/(miK),which is 83.6 times higher than before compression.When the PVDF/Ag fiber membrane before and after compression is placed on a 37 ℃ hot bench,both show a fast temperature rise rate,demonstrating good practical application ability.Also,the PVDF/Ag fiber membrane exhibits excellent mechanical and hydrophobic properties.Compared to existing textiles with thermal conductivity,the PVDF/Ag fiber membrane constructed in this paper with a three-dimensional interconnected thermal-conductive network not only exhibits better thennal conductivity,but also has good mechanical and hydrophobic properties,demonstrating excellent application potential in related fields such as multi-functional textiles and other flexible thermal conductive materials.Furthermore,Ag sheets also have other excellent functions such as antibacterial and electrical conductivity,which is of great guiding significance for the further development of multifunctional textiles and flexible materials.
国家科技期刊平台
NSTL
万方数据
维普
