新穎低表面能材料Polybenzoxazine高分子之應用及其運用於能表面自清潔的超疏水材料之研究

Abstract

在文獻中，我們得知降低高分子表面能的方法大多以加入含氟的化合物或其官能基。而利用高分子的分子間作用力與分子內作用力來改變表面能，此為一嶄新的方向，但相關探討仍屬少見。由於本實驗室發現高分子polybenzoxazine 具有非常低表面能之特性，此特性在高分子中的化學性質與物理性質皆佔有相當重要的影響。 由於polybenzoxazine具有較鐵氟龍更低的表面能，是一個新穎的疏水低表面能材料，除此之外，Polybenzoxazine 較一般常見的含氟低表面能材料價格便宜且具有易於製程的優點。故本實驗為探討高分子polybenzoxazine表面能特性之應用，將以改變新的方法製備出以polybenzoxazine為主的超疏水表面。

本實驗則以polybenzoxazine 為研究主體，研究內容分別為：

1. Polybenzoxazine 本身之低表面能特性研究 本研究室成功利用分子間與分子內作用力(氫鍵)來解釋高分子表面能的變化。此一部分我們則就材料的表面能做學理的研究。

2. Polybenzoxazine 應用於能自清潔的超疏水表面(superhydrophobic and smart surface)之製備與原理探討 超疏水的定義為：水在物體表面的接觸角 (contact angle) 必須大於等於150 度，且滾動角小於10度。物體表面具自清潔之功能是奈米科技時代廣為討論的課題，進行表面處理使其具備超疏水特性是科學家追求的目標。我們則利用噴砂的方法和加入光觸媒奈米粉體（TiO2），使鋁材表面同時具有微米與奈米等級的粗糙結構，並達到像蓮花表面一樣的超疏水特性。我們亦運用最常拿來解釋超疏水現像的兩個學說，來對超疏水特性作學理上的探討。

3.氫鍵和高分子間的分佈對材料表面能量之影響 我們用簡單的熱處理方法可以得到一系列擁有極低的表面能的共聚物poly(vinylphenol-co-methylmethacrylate)。 利用減少高分子間羟基所產生分子間氫鍵作用力原理產生较低表面能的高分子共聚物。 經由红外線分析指出在經過熱處理後，PVPh段的羟基其所產生的分子間氫鍵轉換成自由羥基和羥基和羰基之間的分子內氫鍵,因而使得高分子的分子間氫鍵變小。 另外，我們也發現共聚物poly(vinylphenol-co-methylmethacrylate)氫鍵的強度不僅與高分子的分怖有關且與在旋轉塗佈過程中溶液迅速蒸發速度有關。

In literature, we learned that most researchers add fluorinated functional groups to a given polymer to reduce its surface energy. The change of the surface energy of the polymer is due to the intermolecular and intramolecular force between polymers. Nevertheless, only few studies are related to this research area. Recently, we found that polybenzoxazine has extreme low surface energy which has significant influence on the chemical and physical properties of a polymer. Therefore, studying polybenzoxazine will give us better understanding of the low surface energy property. Polybenzoxazine, due to its lower surface energy than Teflon, is a good alternative for superhydrophobic materials. Moreover, the cost and synthetic procedure of polybenzoxazine are less expensive and simpler than those of other fluorinated materials. In this research, I will study the low surface energy property and the application of polybenzoxazine. In addition, I will also develop new approach for preparing polybenzoxazine for superhydrophobic materials. : The objectives of my research are as follows:

1 The study of low surface energy property of polybenzoxazine: Our lab has already explained the change of polymer surface energy by intermolecular and intramolucular hydrogen bonding. This objective will extend the explanation of this property.

2 The study and new preparation method of polybenzoxazine for smart and superhydrophobic surface: The definition of “Superhydrophobic Surface” is the water contact angle and the rolling angle must be larger than 150° and smaller than 10°respectively. The self-cleaning of the surface of objects is a hot subject in nanotechnology. We will apply sandblasting to create topographical microstructure on the surface of aluminum material. The surface-modified aluminum material is then coated by TiO2 nanoparticles and polybenzoxazine. The resulting composite will have superhydrophobic property like lotus flower surface. Two theories will be used to explain the superhydorphobic property of this novel composite.

3 Effect of Hydrogen Bonding and Sequence Distribution on Low-Surface-Energy Material of Poly (vinylphenol–co-methyl methacrylate) A series of poly(vinylphenol-co-methylmethacrylate) (PVPh-co-PMMA) block and random copolymers possessing extremely low surface energy can be obtained after a simple thermal treatment procedure. PVPh-co-PMMA copolymers result in a lower surface energy because of the decrease of intermolecular hydrogen bonding between hydroxyl groups. Infrared analyses indicate that the intermolecular hydrogen bonding of PVPh segment decreases by converting the hydroxyl group into a free hydroxyl and increasing intramolecular hydrogen bonding and intermolecular hydrogen bonding between hydroxyls and carbonyls after thermal treatment. In addition, we also found that the hydrogen-bonding strength of poly(vinylphenol-co-methylmethacrylate) copolymers not only depended on sequence distribution but also the solvent casting process because of the rapid solvent evaporation during the spin casting process