雙凝聚槽製備PMMA三層結構薄膜之成膜機制探討

Formation mechanism of PMMA sandwich morphology fabricated by dual-coagulant method

蘇順良(Shiun-Lian Su)

指導教授 ： 賴君義

中原大學/工學院/化學工程學系/碩士(2006年)

https://doi.org/10.6840/cycu200600512

摘要

本研究係以PMMA為高分子，利用醇類為第一槽、水為第二槽之雙凝劑濕式成膜方式，製備出上層具lacy-like結構，中間為緻密層，下層則為海綿狀孔洞型態之新穎PMMA三明治結構薄膜。研究中對PMMA三明治結構的成膜過程中，雙凝聚劑對其誘導生成機制作探討。利用FTIR-Microscopy觀察發現以n-propanol為第一槽之醇類時，可誘導PMMA薄膜表層高分子濃度下降；分析薄膜在第一槽中不同滯留時間之結構變化，可以發現在第一槽所生成的Gel態PMMA薄膜表面會有nodule鏈狀顆粒堆疊，主要是由於PMMA薄膜的表層進入unstabe區生成lacy結構，爾後lacy結構會發生斷鏈，因而進一步生成nodule鏈狀顆粒堆疊。
至於第一槽醇類凝聚劑生成Gel態之PMMA薄膜再浸入第二槽-H2O中時，由於Gel態PMMA具不同高分子濃度分布狀態，因而進入第二槽H2O中誘導Gel態薄膜再溶解爾後再次相分離時，可進入不同相分離區中進而生成三層不同結構型態之薄膜。
第一槽之醇類種類改變時，藉著不同醇類與第二槽(H2O)間親和性之不同，可以對薄膜達到結構控制之目的。將利用雙凝聚槽系統製備出之PMMA薄膜應用於親疏水性測試，因其膜面具micro- nano- binary structure，對水接觸角提升最高可達140°。

關鍵字

成膜機制 ； 三明治結構薄膜 ； 薄膜

並列摘要

In the present work, a novel sandwich morphology, a middle dense layer embedded between top lacy layer and bottom sponge porous layers, was prepared by immersing the poly(methyl methacrylate) (PMMA) casting film in the dual-coagulation baths. In the dual-coagulation baths system, alcohol and water were used as the 1st and 2nd coagulant, respectively. The effect of dual-coagulants on the mechanism of membrane formation was investigated.
A gel type PMMA membrane with nodule aggregation on the top surface of gel membrane was formed by immersing the casting film into n-propanol bath (1st coagulant). The analysis of FTIR-Microscopy shows that the PMMA polymer concentration in the top layer of the nascent membrane decreased as immersing the casting film into n-propanol bath (1st coagulant). The lacy structure can be formed in the n-propanol bath, resulted from the composition of dilute PMMA polymer solution in the top layer was entered into the unstable region. The lacy structure would break to form nodule and then aggregated as increasing the immersion time in the n-propanol bath.
The n-propanol bath formed gel PMMA membrane would resolve and then demixing again by immersing into the water bath (2nd coagulant). It is considerate that the gel membrane can arise different phase separation mechanism and would be happened in each depth of resolved solution, resulted from the various polymer concentration distributions by immersing the gel membrane into water bath.
By using different alcohol as the first coagulant in the dual-coagulants process, the exchange rate between alcohol and water, the residual solvent in the gel membrane and water can be controlled and led to control the morphology of PMMA membrane. The 140° water contact angle can be gotten due to the formation of micro-nano-binary surface structure by using the dual-coagulants method to fabricate PMMA membrane.

並列關鍵字

membrane formation ； sandwich structure

參考文獻

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