以非毒性溶劑製程製備 PDMS 薄膜應用於氣體分離之研究

Abstract

本研究希望能夠透過非毒性溶劑的方式來進行 Polydimethylsiloxane (PDMS，聚矽氧烷高分子)薄膜的製備，並且探討不同的交聯程序參數對於 薄膜的結構與交聯特性之影響，並評估 PDMS 薄膜的氣體滲透特性。因此 研究中會透過電子顯微鏡(FESEM)、原子力顯微鏡 (AFM)、黏滯度分析儀 (Viscometer)及傅立葉紅外線轉換光譜儀(FTIR)，來進行 PDMS 薄膜之結構 特性和交聯特性的觀察，並以單一氣體滲透來探討薄膜的滲透特性。 研究結果顯示，確實可以透過含有 3.0 wt. % 4-Dodecylbenzenesulfonic acid (DBSA)水溶液當溶劑製備出有緻密型態的 PDMS 薄膜。同時透過黏滯 度比較 不同 交聯 劑 Tetraethyl orthosilicate (TEOS ，正 四乙 烯 基矽氧 烷 C8H20SiO4)添加量與交聯溫度之影響。發現 TEOS 添加量與交聯溫度確實 會影響到其交聯反應之速率。且發現在不同黏滯度下進行塗佈，會影響薄 膜的結構型態與氣體滲透特性。當黏滯度低時，形成較薄的 PDMS 層於基 材表面，對 H2/CO2 有較高的滲透與分選能力，當 TEOS 添加量為 9.4 wt. % 時 (PS9)，可以看到 H2 的滲透通量可以到達 600 GPU 與 H2/CO2 分選率為 3.45；另外在黏滯度較高時，可以製備出較緻密的 PDMS 薄膜，其對於 CO2 有較高的滲透特性，當在 TEOS 添加量為 15.8 wt. %時 (PS15)，CO2 的滲 透通量大約為 430 Barrers，CO2/H2 分選率大約 10。並且透過固化溫度的 提升，可以提升薄膜結構的穩定性，提升其耐塑化的特性。.

In recently, many researchers hope to find the green and clean chemistry processes to reduce environmental problem. This study focus on polydimethylsiloxane (PDMS) membrane which was fabricated through the non-toxic solvent method. Comparing with three solvents (n-Hexane, Deionized water and containing 3.0wt% 4-Dodecylbenzenesulfonic acid (DBSA)), the effect of crosslinking process was discussed by the viscosity property of casting solution. To study the correlation between the different preparation parameters and the structure and permeation properties of PDMS membrane. Therefore, we would use scanning electron microscope (FE-SEM), atomic force microscopy (AFM), viscosity analyzer and Fourier transform infrared spectroscopy (FTIR) in this study, to identify the morphology and cross-linking properties of PDMS membrane. The dense PDMS membrane was prepared successfully by 3.0 wt. % DBSA solvent. The results showed that the amounts of TEOS and crosslinking temperature would affect the rate of crosslinking reaction. Moreover, the viscosity of casting solution was also the important factor. When the viscosity of casting solution was low, the thin PDMS layer was permeated on the substrate surface, which had higher H2/CO2 selectivity. In contrast, the dense PDMS membrane was formed on substrate when the more viscous casting solution, which have the higher the permeability of CO2. On the other hand, the curing process of high temperature can enhance the stability of the membrane structure, and improve resistance-plasticizing in high pressure permeation.