硬質薄膜通常應用在塑膠基材上作為保護層，為基材延長使用壽命。而薄膜被廣泛地透過溶膠凝膠法製造。本研究中，以PET軟性基材作為基底，具有超親水性的雙層結構薄膜被成功開發出來。雙層薄膜結構中，底層為硬質薄膜，是利用含壓克力官能基的二氧化矽溶液(Modified silica sol.)、戊二醇四丙烯酸酯（PETTA）、光起始劑(DC 1173)混合後塗佈而成，其固化後的交聯網狀結構為薄膜整體提供了優異的機械性質；上層為超親水薄膜，是使用四乙氧基矽烷（TEOS）在鹼催化環境下形成的超親水奈米顆粒，在薄膜表面作表面改質，提高薄膜表面能，以致於達到防霧效果。 本實驗利用UV / VIS分光光譜儀，原子力顯微鏡（AFM），水接觸角量測儀，鉛筆硬度計，附著力測驗、耐磨測驗，防霧測驗，浸泡試驗以及耐久性試驗等各種方法來檢測薄膜各方面性能。由實驗結果可知，交聯劑的添加量會直接影響到薄膜的硬度以及親水性質。特別的是，隨著交聯劑的添加，薄膜的硬度會顯著提高，原因是交聯劑具有多個壓克力反應官能團，薄膜固化後會擁有緻密的結構，然而，由於交聯劑的高交聯密度性質，會導致薄膜在固化後表面形成全面性的皺褶結構，令薄膜表面表現不出超親水性質。 實驗結果顯示，超親水硬質薄膜不僅具有優異的硬度（4H），且具有良好的光學性質(平均穿透率89.83%，400-700nm)及防霧性質(100°C熱水上5秒不起霧)，因此可應用於於許多產業上。 ;Superhydrophilic hard coatings are frequently applied on plastic substrate as a protective layer. The coatings have been recently widely fabricated by sol-gel processes. Here, a bilayer hard coatings with superhydrophilic performance was developed on polyethylene terephthalate (PET) substrate using modified sol-gel processes. The bottom coating, UV curable hybrid hard coating, is an organic/inorganic composite comprising surface-modified silica with acrylic groups embedded in pentaerythritol tetraacrylate (PETTA) cross-linked network to provide a mechanical support. The upper coating was modified using superhydrophilic nanoparticles, which synthesized by tetraethoxysilane (TEOS) in base catalyst. Various methods, e.g., UV/VIS spectrophotometer, atomic force microscopy (AFM), water contact angle, pencil hardness test, adhesion test and abrasion-resistant test, anti-fogging test, soaking test, durability test were employed to characterize the film performance. The results indicated that the amount of PETTA was deeply affect hybrid hard coatings characteristics. Especially, the hardness of hybrid hard coatings significantly improved with the addition of PETTA, due to the PETTA has four reaction functional groups. The optimal bilayer superhydrophilic hard coatings has not only excellent hardness (4H) but also superior flexibility. It also exhibited that superhydrophilic properties (WCA<10°) were effectively improved after applying the superhydrophilic nanoparticles on the hybrid hard coatings surface. The average transmittance (400-700 nm) of the coatings also increased by applying the nanoparticles layer efficiently. It demonstrated that the bilayer hybrid hard coatings can be applied on many industries.
