本研究利用濕式相轉換製備聚偏二氟乙烯(PVDF)與聚甲基丙烯酸甲酯(PMMA)之複合薄膜，溶劑為二甲亞風(DMSO)，非溶劑為水與DMSO。藉由不同濃度之沈澱槽(純水、40％DMSO、70％DMSO)製作出不同型態之複合薄膜，並以SEM、拉力試驗機、DSC、XRD來作測試。隨著PMMA的加入，薄膜之SEM有明顯的差異；抗張強度漸漸上升；薄膜之T/sub m/漸漸下降；XRD繞射峰逐漸減弱，顯示其結晶度有下降的趨勢。在沈澱槽影響方面，70％DMSO沈澱槽製備之薄膜有較好之結晶度，也可由SEM、DSC、XRD等測試中證實。 In this research, PVDF/PMMA composite membranes were prepared by the isothermal immersion precipitation method. DMSO and water were used as the solvent and nonsolvent, respectively. A wide variety of membrane morphologies were obtained by changing the bath conditions and/or the ratio of the two polymers. SEM, DSC, XRD, and tensile strength tester were used to study the morphologies and physical properties of the membranes. As the composition of PMMA increased, the morphology of the membrane underwent profound changes from more particulate to more cellular form. The tensile strength also gradually increased in this case. That the T/sub m/, H/sub m/, and XRD diffraction peaks decreased with increasing PMMA content suggested that the crystallization capability of PVDF was lowered by blending with PMMA. As to the effects of the precipitation bath, it was found that precipitation in baths containing high concentrations of DMSO tended to yield membranes with high crystallinity, which was confirmed by SEM, DSC, and XRD analysis.