For films with different structures, the gas transmission and diffusion modes through the film are different, and the permeation mechanisms are also different.
There are two mechanisms for gas permeability through polytetrafluoroethylene breathable membranes: one is the dissolution and diffusion mechanism through non-porous membranes; the other is the micropore diffusion mechanism through porous membranes. The gas transfer mechanism in porous media includes Knudsen Diffusion, viscous flow, surface diffusion flow, molecular sieving, capillary condensation, etc.
Due to the differences in the properties of the pores and the inner surface of the pores, the degree of interaction between gas molecules and porous media is different, thus showing different transfer characteristics.
PTFE breathable membrane is a porous membrane. The membrane structural parameters and the properties of the permeable gas determine the gas permeability. The membrane structural parameters include thickness, porosity, pore size, etc., and the gas molecule characteristic parameters include gas molecules. free path, molecular weight, viscosity, etc.
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