新穎低表面能高分子研究及其在奈米壓印系統與超疏水表面之應用和學理探討

Abstract

高分子領域中，化學性質與物理性質皆具有相當的重要性，且兩者是相輔相成的。我們可藉由化學改質的方法來滿足某些物理性質的需求、或以物理性質研究來延續合成產物的應用性與實用性。本論文以polybenzoxazine為研究主體，內容分列為三大主題：

1. Polybenzoxazine本身之低表面能特性研究 在以往的文獻中，降低高分子表面能的方法大部分是加入含氟的化合物或官能基。利用高分子的分子間與分子內作用力來改變表面能，為一嶄新的方向，相關研究仍屬少見。本研究中，我們發現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，此外，我們成功利用分子間與分子內作用力(氫鍵)來解釋改變高分子表面能的變化。Polybenzoxazine 較一般常見的含氟低表面能材料具有價格便宜與易於製程的優點。

2. Polybenzoxazine應用超疏水表面(superhydrophobic surface)的製備與原理探討 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。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。我們利用電漿改質，使polybenzoxazine表面具有微米與奈米等級的粗糙結構，並達到超疏水特性。此外，我們亦運用polybenzoxazine本身的疏水特性結合奈米粉體，研發出一可在所有pH值中保持超疏水特性的表面。我們亦計畫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. polybenzoxazine應用於奈米壓印微影(nanoimprint lithography)系統 奈米壓印技術是一種成本較低之奈米製造技術，為近年頗受重視的科技，主要包含兩個步驟：壓印(imprinting)和圖案轉移(pattern transfer)。在壓印過程中，母模與高分子阻劑之間的黏著情形是造成轉印圖案毀損的主要原因。在本研究中，我們利用polybenzoxazine的低表面能特性，克服高分子阻劑沾黏的問題，在高分子表面製造出奈米圖形。

The physical and chemical properties are both important in the polymer researches. We can enhance many properties of polymers by chemical methods (i.e. variation of the functional groups). By doing detailed studies of physical properties of polymers , we can discover numerous applications of them. In this study, we focus on three major subjects which based on the polybenzoxazines:

1. Low surface free energy materials based on polybenzoxazines We discovered that polybenzoxazines can possess surface free energies even lower than that of pure poly(tetrafluoroethylene) (Teflon). We monitored the contact angles and surface free energies, based on the Lifshitz-van der Waals acid-base theory, during the polymerizations of benzoxazines. By combining results we obtained from surface free energy and Fourier transform infrared spectrocopic analyses, we found the relationship between the hydrogen bonding and the surface free energy. These polybenzoxazines comprise a new class of low-surface-free-energy material, they are cheaper to prepare and easier to process than are conventional fluoropolymers and silicones.

2. Superhydrophobic polybenzoxazine surfaces Superhydrophobic surfaces (water contact angle > 150°) have attracted much interest because of potential applications in daily life as well as in many industrial processes. One method to improve the liquid repellency of a surface is to combine a suitable chemical structure (surface energy) with a topographical microstructure (roughness). In this section, we report two methods to create superhydrophobic polybenzoxazine surfaces. Firstly, we produce super-amphiphobic surfaces through plasma modification of benzoxazine films. Secondly, we contribute a simple two-step casting process to create a stable superhydrophobic surface.

3. Polybenzoxazine as a Mold Release Agent for Nanoimprint Lithography Nanoimprint lithography (NIL), a high volume and cost-effective patterning technique, is potentially great as a candidate for next generation lithography. One of the most important problems usually encountered for NIL is the tendency for the resist polymer to adhere to the mold during mold release. This new class of low surface free energy material called polybenzoxazine provides an efficient mold release agent for silicon mold which is easier to process, costs low, and has no side reaction.