| 초록 |
Materials with aligned porous structures have broad potential in applications such as separation/purification, fuel cells, catalysts, and tissue engineering. We could produce this aligned porous film from PVDF (polyvinylidene fluoride) by unidirectional freezing in nitrogen liquid and subsequent freeze drying or etching to remove solvent crystals. We analyzed the difference of solvent removing methods between freeze drying and etching process. In general the film prepared by directional freezing was too weak to be a free-standing membrane but we enhanced mechanical properties by using not only suitable polymer and precise control of freezing rate and direction. Solvent etching process generally produced quite stronger films too. Directional freezing is a simple, cheap, and novel route to prepare aligned porous materials in the form of 2D surface patterns or 3D monolithic structures. Additionally we can control pore size and films structure by freezing rate and dispersion concentration. |
