含氟之高性能聚亞醯胺薄膜之表面特性分析與 應用

Abstract

在過去數十年間，聚亞醯胺(Polyimide,PI)已是一種廣泛被使用的高分子材料且擁有良好的熱性質、化學性質與機械強度。這些優點讓聚亞醯胺在過去的時間內都被當作是高效能之高分子應用材料的良好選擇。為了特定的應用需求，含氟聚亞醯胺也被開發研究，並被證實擁有許多一般聚亞醯胺沒有的優點。同時含氟聚亞醯胺也因為在有機溶劑中有好的可溶性，是製程簡化與加工處理的好選擇。而在最近幾年，聚亞醯胺塗膜根據需求，又更被進一步地開發出許多新的應用，包括防腐蝕、生醫材料等等一些新穎的用途。在這份博士論文中，含氟聚亞醯胺薄膜可經由不同的處理，包括奈米粒子表面噴塗與以單體置換方式形成共聚高分子，我們將其製備成不同特性之聚亞醯胺薄膜，分別應用在抗腐蝕與生醫材料等不同用途上。

在博士論文第一個部分，我們將矽氧甲基封端的氟化之二氧化矽奈米粒子噴塗在聚亞醯胺表面，來調整聚亞醯胺的表面形貌及化學特性，使其成為抗腐蝕且超疏水的聚亞醯胺複合材料。根據分析，矽氧甲基封端的氟化之二氧化矽奈米粒子噴塗大幅提升材料表面粗糙度，並使表面佈滿疏水的CF2官能基，因此能達到超疏水的效果。而這層噴塗也使這複合材料擁有較低的腐蝕電流密度、高腐蝕電位及腐蝕阻抗，在在顯示其擁有良好的抗腐蝕特性。經由矽氧甲基封端的氟化之二氧化矽奈米粒子噴塗，不但讓聚亞醯胺擁有超疏水的特性，並可隔絕造成腐蝕的因子到達金屬表面，進而提升聚亞醯胺塗附之金屬的抗腐蝕能力。這項技術不單能提供聚亞醯胺鍍附之金屬材料好的抗腐蝕能力，並且也能運用在其他高分子鍍膜材料上。

在第二個部分，我們將含氟聚亞醯胺的單體部分置換成親水的單體Jeffamine，控制其置換比例是10、20及30%，來置備出新型共聚亞醯胺薄膜(6FPI-Jx，x=10、20和30%)。在過去，雖然含氟聚亞醯胺被認為有在生物醫學領域上應用的潛力，但是其潛在的細胞毒性是應用上最大的問題。在這篇論文中，親水的胺基封端之聚醚分子Jeffamine被作為共聚亞醯胺的單體被摻入。經過適當的製程控制，此共聚亞醯胺如同一般聚亞醯胺，具有好的機械性質與穩定性。根據分析，將部分單體置換Jeffamine使得含氟聚亞醯胺的細胞毒性降低，並大幅提升其生物相容性與血液相容性，我們相信這樣的提升是來自於Jeffamine的加入，產生了材料表面結構與化學組成的變化所致。另外，共聚亞醯胺的可溶性也獲得保留，在此研究中我們也展示了此共聚亞醯胺能在金屬基材上行成均勻的鍍膜，我們相信此種新型共聚亞醯胺是成為人體植入物外層鍍膜的良好選擇，並且也預見這在未來治療的應用上有良好的潛力。

During the past several decades, Polyimide (PI) is already a widely used polymer in industries and exhibiting good thermal, chemical, and mechanical properties. These merits render PI a perfect candidate in high-performance engineering applications. To fit for specific purpose, fluoro-containing PI is developed and possesses additional advantages over common PI. Fluoro-containing PI is also soluble in many kinds of organic solvent, rendering a option for simplified operation and better processability. Till recently, new applications of PI coatings have been further investigated, including anti-corrosion and biomedical uses. In this dissertation, high performance fluoro-containing PI films were prepared through different modification process, such as spray-coating of modified nanoparticles and copolyimidization through monomer substitution. The application of modified PI films in anti-corrosion and biomedical uses were deeply explored in this research.

In the first section of this dissertation, we prepared superhydrophobic PI hybrid coatings for anticorrosion application by adjusting their surface roughness and surface composition through spray-coating with silylated perfluoroalkylsilane-modified organosilicasol (silylated fluoro-organosilicasol), which increased the surface hydrophobicity. After silylation with 1,1,1,3,3,3-hexamethyldisilazane (HMDS), the silylated fluoro-organosilicasol further transformed the PI surface into a superhydrophobic state. According to the analyses, it suggests that both surface roughness and silylation of the fluoro-organosilicasol making more CF2 groups on the outmost surface rendered the surface hydrophobicity. These PI hybrid coatings also demonstrated good anti-corrosion performance such as lower corrosion current density, nobler corrosion potential and higher polarization resistance. The enhancement in anticorrosion performance was believed to be contributed from the superhydrophobicity and dual barrier protection from the fully-covered fluoro-organosilicasol, insulating the metal from corrosive species in the medium. This superhydrophobic coating technique with good stability guaranteed better corrosion protection and also has great potential for application to other polymeric films.

In the second section of this dissertation, a brand-new class of Jeffamine-modified fluoro-containing polyimide (denoted as 6FPI-Jx series, where x is ranging from 10, 20, and 30%) was developed. Although existing pristine fluoro-containing polyimide has been considered as promising biomaterial for its good blood compatibility, it has known to be toxic to normal cells. Here, we modified fluoro-containing PI by incorporation of hydrophilic monomer, Jeffamine, which is a commercial polyether diamine product line from Huntsman. Through systematically characterization, the 6FPI-Jx copolymer exhibited good mechanical and stability as pristine 6FPI. Especially when addition of Jeffamine equal of 10%, 6FPI-J10 displayed considerably improved blood and cell compatibility compared to 6FPI, which was explainable as a combined effect of morphological texture and chemical environment of resulting surface. The new class of 6FPI-Jx also exhibited excellent solubility toward a number of organic solvents. The capability of forming homogeneous 6FPI-J10 coating on stainless steel substrate is demonstrated in this research, showing the 6FPI-J10 a great potential candidate as biocompatible coating for implantable medical devices and also for potential therapeutic applications.