新穎低表面能高分子研究及超疏水至親水間可逆濕潤性控制之探討

Abstract

摘要

本論文中以開發新型的不含氟之低表面能高分子為主體，分為三大主題:

1. 酚醛樹酯-多面體聚矽氧烷奈米複合材料之熱性質與表面性質研究 多面體聚矽氧烷( Polyhedral Oligomeric Silsesquioxane) 由於其具備容易經由有機方法改質，使其與高分子間相容性增加而得以製備有機-無機奈米複合材料，在近年引起廣泛的研究。我們製備了一新型含八酚官能基之多面體聚矽氧烷，並將其與酚和甲醛共聚製備出新型酚醛樹酯奈米複合材料。我們發現此奈米複合材料之熱性質與低表面能方面均有優異的表現。此外，我們成功證明了多面體聚矽氧烷的無機核心傾向於在材料表面形成一保護層，成為熱性質大幅提升的原因。

2. Poly(vinylphenol) 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。利用操控高分子的氫鍵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 poly(vinylphenol) 經過一簡單的熱處理程序後具有較鐵氟龍更低的表面能。我們比較 poly(vinylphenol) 與 polystyrene 之雜亂式共聚高分子、團聯式共聚高分子與混攙之表面能與氫鍵變化，進一步證實氫鍵強度變化與表面能之間的關連。此項研究提供了一相當簡便的方式來製備不含氟亦不含矽氧烷之低表面能高分子材料。

3. Polybenzoxazine/矽奈米粒子薄膜之超疏水至親水間可逆濕潤性探討 對於外在條件具有響應的可逆濕潤性薄膜，近年來引起相當多的研究興趣。但是為了同時兼具可逆濕潤性以及表面之粗糙度，許多文獻上的製備方法均過於繁瑣或昂貴。我們利用矽奈米粒子表面之親水官能基製備出一系列具有對溶劑響應之可逆濕潤性的高分子薄膜。此方法的優點在於攙入之矽奈米粒子除了提供可逆響應的平台之外，亦同時提供了足夠的粗糙度使此薄膜具有超疏水至親水間之可逆濕潤性。我們並針對攙入奈米粒子含量、浸潤時間以及烘乾時間做一探討。

Abstract

In this study, we focus on three major subjects which based on non-fluorine low surface energy materials:

1. Thermal and Surface Properties of Phenolic Nanocomposites Containing Octaphenol Polyhedral Oligomeric Silsesquioxane POSS (Polyhedral Oligomeric Silsesquioxane) molecule, which contains organic substituents on its outer surface that make the POSS nanostructure compatible with polymers, arouse much attention in recent years. We synthesized a new polyhedral oligomeric silsesquioxane (POSS) containing eight phenol functional groups and copolymerized it with phenol and formaldehyde to form a novolac type phenolic/POSS nanocomposites containing high thermal and low surface energy properties. The incorporation of POSS leads to the formation of a surface barrier that minimized the direct contact of the polar phenolic units with the air. The presence of such a barrier not only enhanced the thermal stability of the bulk and surface of these POSS-containing composites but also led to the surface energy being maintained after treatment at high temperature.

2. Effect of Intermolecular Hydrogen Bonding on Low-Surface-Energy Material of Poly(vinyl phenol) We discovered that the poly(vinyl phenol) (PVPh) possesses extremely low surface energy (15.7 mJ/m2) after a simple thermal treatment procedure, even lower than the poly(tetrafluoroethylene) (PTFE) (22.0 mJ/m2) calculated based on the two-liquid geometric method. In addition, we also compared surface energies of PVPh-co-PS copolymers (random and block) and their corresponding blends, these random copolymers possess the lowest fraction of the intermolecular hydrogen bonding and surface energy than the corresponding block copolymers or blends after similar thermal treatment. This finding provides a unique and easy method to prepare a low-surface-energy material through simple thermal treatment procedure without using fluoro-polymers or silicones.

3. Reversible Wettability of a Polybenzoxazine-Silica Hybrid Surface between Superhydrophobicity and Hydrophilicity Recently, reversibly controlling the surface wettability has aroused great interest and been demonstrated by various methods, however, multistep processes, stringent preparation specification, and the high cost of forming large-area environmentally responsive surfaces have heretofore limited their practical applications. Herein, we report on a simple two step process to create a roughness-enhanced solvent responsive wettability of a polybenzoxazine-silica hybrid surface. The silica nanoparticles modified with hydroxyl groups should be able to express hydrophilicity by responding to external stimuli. Reversible switching between superhydrophobicity and hydrophilicity can be achieved by repeatedly immersing the surface into selective solvents and drying it in vacuum.