The team of Yu Jianyong of Donghua University has developed a nanofiber membrane, which not only has good waterproof and moisture permeability, but also has excellent air permeability and thermal conductivity. It is made of a unique polymer matrix (polyurethane), hydrophobic fluorinated polyurethane, and high thermal conductivity BN nanosheets mixed and electrospun. The researchers obtained the result by controlling the loading rate of the BN nanosheets and the relative humidity (RH) of the environment. A BN network with good interpenetration is established, and the porous structure of the BN network lays a good foundation for the air permeability and thermal conductivity of this membrane. At the same time, the synergistic effect of the hydrophobic polymer matrix and the improvement of the surface roughness of the membrane make this membrane also have good water permeability resistance and superhydrophobicity.
The specific manufacturing process of this film is to make a spinning dope by dissolving FPU and DMAc and dispersing BN nanosheets at the same time, and then electrospinning FPU/BNx film after ultrasonic treatment (x is the concentration of BN nanosheets) . The concentration of FPU is 6%, wherein the mass ratio of fluorinated polyurethane/polyurethane is 1/8, and the mass fraction of BN nanosheets are 0%, 6%, 12%, 18%, and 24%, respectively.
This research was published in the journal ACS Applied Materials and Interface on June 19 this year.
1. Thermal conductivity test
After testing, the ultra-high in-plane thermal conductivity of this film is 17.9 W/m · K, the cross-sectional thermal conductivity is 0.29 W/m · K, and the high water vapor transmission rate (WVT) is 11.6 kg / m2 · day . Through the modeling and calculation of the highest temperature, the difference in thermal conductivity of FPU/BN0 film, FPU/BN18-RH90 film and FPU/BN18-RH50 film can be clearly seen:
2. Hydrophobicity test
After testing, the water contact angle of this membrane is 153°, and the hydrostatic pressure is 32 kPa.
3. Air permeability test
This nanofiber membrane can not only be used in sportswear to help the human body achieve more comfortable body temperature management, but also can be used in building materials to reduce the total energy consumption of building space cooling by exerting its air permeability, heat conduction and waterproof properties , Is conducive to future sustainable development.
