摘要:官能性的聚對二甲苯家族可視為是一群多用途的功能性高分子,藉由化學氣相沈 積製(CVD)程控制技術,可製備出無針孔之奈米級薄膜,並可蒸鍍在不同的基材上,使 基材表面具備多種反應性官能基;此外,此功能性高分子薄膜可利用化學鍵結的方式, 將特殊功能性之活性分子如:蛋白質、酵素、抗體...等固定於薄膜表面,賦予高分子 薄膜具有生物功能性,可廣泛的應用於生物材料及生醫器材表面加工改質技術之中。 在此為期三年的研究中,我們計畫合成多種具不同官能構造的功能性聚對二甲苯鍍 膜。根據我們研究團隊先前開發的聚合體為藍本,我們將在此研究計畫中研發出更多 具有特殊官能基以及有特殊功能的聚對二甲苯。例如像是延伸配對的π-電子系統或是 具備氫鍵結合的能力。在使用化學氣相沉積(CVD)合成聚對二甲苯之前,我們首先將製 備其相對應的[2.2]對環芳烷單體,同時將對聚合製程的最適化進行系統化的研究。第 一年的計畫中,研究重點包括官能性的聚對二甲苯化學上與結構上的分析、薄膜的黏 著力分析、穩定性,以及對其物理機械特性、分子傳輸性質進行研究。在計畫的第二 年,分析研究將著重於分子的晶體結構、分子鏈運動特性、光學性質的分析(例如 n, k, birefringence)以及聚合物薄膜的局部塑性都將是研究的重點。同時我們將以聚對二甲苯 薄膜為模型,作為研究官能基特性對玻璃化溫度(Tg)的影響。分析的儀器與方法包括 X 射線光電子能譜(XPS),傅立葉轉換紅外線光譜(FTIR),Raman 光譜,橢圓光度法 (ellipsometry),廣角 X 光繞射(WAXD),掃描式熱差分析(DSC)。我們預期第一、第二 年的研究結果將有助於我們深入了解不同之官能基特性與聚對二甲苯分子結構之對應 關係。我們團隊先前的研究顯示經過化學蒸鍍(CVD)所製備的官能性聚對二甲苯鍍膜具 有極佳輪廓包覆性,即便是在基材表面的次微米級構造也能達到良好的鍍膜包覆效 果。這些亮眼的特徵使得官能化聚對二甲苯成為研究「基材的性質對薄膜性質所造成 的影響」的絕佳模型。我們將會有系統地改變基材的化學性質(透過金屬沈積製程)以及 改變表面的拓譜(透過微機電系統製程),並著手研究這些改變對薄膜玻璃轉移(glass transition)的影響。第三年,我們將發展出一套化學蒸鍍聚合與其相對應官能性的聚對 二甲苯製程參數最適化的設計法則,同時結合第一、二年研究所熟悉之聚對二甲苯分 子結構特性,我們將著手研發製備更先進、同時具有特殊功能之聚對二甲苯,例如利 用化學蒸鍍共聚法(co-polymerization)製備多功能性(multi-functional)官能化聚對二甲苯 以及梯度型高分子鍍膜(polymer gradients)。其所製備的多功能性官能化聚對二甲苯可 同時具備不同的官能基分子,並獨立發揮固定生物分子的功能;另一方面,梯度型高 分子鍍膜具備連續性的化學官能梯度,可續經由固定生物分子的技術來提供梯度化的 生物訊息(biological information)。此計畫所研發之功能性聚對二甲苯將為生物表面界面 工程技術提供強而有力的工具,未來將計畫跨學門研究合發展並著眼於仿生功能性材 料、組織工程,微流體系統、生物探測技術、或是微陣列應用等領域。
Abstract: Functionalized poly(p-xylylenes) constitute an versatile class of Reactive Polymers that can be prepared in a solventless process via chemical vapor deposition (CVD) polymerization. The resulting ultra-thin coatings are typically pinhole-free and can be conformally deposited onto a wide range of substrates and materials. More importantly, appropriately selected functional groups can serve as anchoring sites for tailoring of biointerface properties via immobilization of biomolecules.
During this three-year project, we will synthesize a library of functionalized poly-p-xylylenes with diverse molecular properties. In addition to the polymers recently synthesized in our group, we will prepare novel poly-p-xylylenes with critical features, such as extended conjugated π-electron systems, or hydrogen bonding ability. Prior to the polymer preparation via CVD polymerization, the corresponding [2.2]paracyclophanes will be synthesized and the polymerization process will be optimized. In this phase, the major analytical focus will rest on chemical and structural properties, film adhesion, and stability; followed by the analysis of mechanical, and transport properties of functionalized poly-p-xylylenes. With the beginning of year 2, the analytical focus will shift to fundamentally motivated studies that target crystallization, chain mobility, optical properties (e.g., n, k, birefringence), and local plasticity in thin polymer films. Functionalized poly-p-xylylenes will serve as the model system to study the effects of side group structure on the glass transition applying a combination of analytical methods including X-ray photonelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, ellipsometry, wide angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC). A correlation with the structural information gathered during the first two years of the project will reveal interesting structure-function relationships. We have already shown that the CVD polymerization of [2.2]paracyclophanes can result in highly conformal coatings with excellent contour coverage; even on substrates with sub-micron topology. These eye-catching features make functionalized poly-p-xylylenes promising model systems for studying the influence of the nature of the substrate on thin film properties. We will systematically vary the substrate chemistry (via metal deposition) and topology (via microfabrication) and will examine the effects on glass transition. In year 3, a unifying molecular model will be developed that is capable of predictive design rules for polymer selection and the choice of CVD polymerization parameters. The new molecular understanding of functionalized poly-p-xylylenes will inspire novel synthesis efforts including the preparation of co-polymers with multiple functional groups and polymer gradients. For instance, co-polymers with side groups that do not exhibit intermolecular cross-reactivity are useful for defined surface attachhment of multiple ligands (orthogonal immobilization). Polymer gradients can provide continuously varied chemical composition and biological information. These studies may pave the way for interdisciplinary collaborations with the aim to develop surface engineering solutions for novel applications, such as functional biomaterials, microfluidic devices, biosensors, or microarray applications.