本篇研究主要為探討以非溶劑誘導相分離法(non-solvent-induced phase inversion, NIPS)製備聚偏氟乙烯(polyvinylidenefluoride, PVDF)多孔薄膜，並探討將其應用於薄膜蒸餾應用的可行性。所探討之項目可分為兩大項，其一為以不同碳鏈之咯烷酮類離子液體作為造孔劑對於薄膜結構的影響；第二項為探討以相分離法製備的薄膜對於薄膜蒸餾系統效能評估。
在相分離法的過程中，各個相的組成對於最終所得到的薄膜結構有很大的影響。本研究中添加的離子液體添加於鑄膜液相，以延遲相轉換的速率，進而得到不同的結構。與未添加離子液體的薄膜做比較，可以發現由於分層的時間延遲，使得薄膜的斷面及下表面由本來的指狀結構轉化成緻密的海綿狀微孔結構；而這樣的結構增強了薄膜表面的粗糙度和疏水性。此外，FTIR及XRD的分析，發現PVDF的結晶相受到改變，可以推測PVDF在極性環境下其分子鏈段的排列將會受到改變，而產生不同的結晶態。
而在薄膜蒸餾系統的評估中，可以發現添加了離子液體的薄膜其通量及導電度的穩定性皆比對照組優異。由於薄膜疏水性上升後，使得進料端的水不易吸附於薄膜表面，且海綿狀的膜孔結構有利於水蒸氣通過薄膜，使得透過液的鹽濃度與通量能夠維持穩定。在與商業膜比較時，可發現以1%NMP IL所製備的薄膜其效能與商業薄膜最接近，由此可見以相分離法製備的薄膜於薄膜蒸餾之應用具有相當的潛力及發展性。

In this study, poly(vinylidene fluoride) (PVDF) membranes were prepared through non-solvent induced phase separation (NITPS) technique for membrane distillation (MD) applications. Ionic liquids were used as porogen and added into casting solution composing of PVDF and N-methyl-2-pyrrolidone (NMP) to obtain porous PVDF membranes. The resulting membranes were characterized systematically including Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), and contact angle measurement. According to the results of FTIR-ATR and XRD, the crystalline phase of PVDF was predominated by β phase. Based on the SEM and AFM observations, the surface morphology of PVDF membranes became rougher due to the addition of ionic liquids. Furthermore, MD test revealed that PVDF prepared from NMP ionic liquid has the best efficiency on preventing leakage of salt. Thus, this study demonstrated that PVDF membranes prepared by adding ionic liquid can serve as a promising candidate for membrane distillation applications.

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