| 초록 |
We fabricated porous membrane with asymmetric pore sizes across the film thickness by using phase inversion method. For this purpose, polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) solution in THF/DMF solvent was coated on a silicon wafer by using a doctor blade. During the short times (30 s exposure in air), THF was vaporized from the film surface, which induces vertical orientation of cylindrical PMMA microdomain on the top layer of the membrane. When this membrane was immersed in water, microphase-separated morphology was fixed. However, larger pores are produced in the middle to bottom layers of the film due to the exchange of the mixed solvent of THF/DMF with water. The pore size and shape through the entire film thickness was characterized by scanning electron microscopy. |
