摘要 |
A coating liquid containing a polymer and a hydrophobic solvent is applied to a support to form a coating film. Water vapor is condensed from ambient air on a surface of the coating film. A hydrophobic solvent is evaporated until a content rate of the solvent in the coating film reaches 50 wt %. The coating film is caused to contact with liquid water. The hydrophobic solvent contained in the coating film is moved from the coating film to the water. The water and the solvent are evaporated from the coating film. Thus, a porous film having a plurality of pores is produced. It is unnecessary to adjust a surface temperature of the coating film and a dew point of the gas around the coating film precisely. It becomes possible to evaporate the hydrophobic solvent contained in the coating film rapidly.
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