運用奈米限制聚合在水中製備活性聚苯乙烯奈米粒子

Synthesis of polystyrene living nanoparticles(LNP) in water via nano-confined free radical polymerization

張維庭(Wei-Ting Chang)

指導教授 ： 王建隆

國立交通大學/理學院/應用化學系所/碩士(2020年)

摘要

自由基 (Free radical) 是引發化學反應中相當重要的基礎。其擁有高度的反應性，可以快速地將分子進行聚合等反應機制，然而，在高分子化學中要實現末端帶有自由基之聚合物是一件艱難的工作，無法利用小分子的立體阻礙和電子共振來穩定活性自由基。因此我們想到以外部親水、內部疏水的單分子微胞作為外殼形成立體阻礙，我們使用了具有八隻雙親性手臂、核心為 POSS 的星狀大分子作為我們的奈米反應器 (UM & UM2)，透過動態光散射與小角度 X 光散射的結果確立了此奈米反應器在水中呈現平均尺寸為 10 奈米左右的單一分子球型微胞，進而在內部疏水空腔進行苯乙烯單體的包覆以及奈米限制聚合反應以得到單一活性聚苯乙烯高分子鏈，並且藉著微胞的特殊性質，降低了高分子鏈自由基耦合的可能性。藉由核磁共振儀、紫外-可見光光譜儀、凝膠滲透層析儀，我們證明了 PSt/UM & PSt/UM2 是具有活性並且能夠起始單體聚合，形成類似於活性高分子鏈的活性奈米粒子。活性奈米粒子的出現將是空前的研究，將為製備奈米物種帶來一個新的道路。

關鍵字

活性聚合物 ； 自由基聚合 ； 主客體化學 ； 單分子微胞 ； 聚苯乙烯

並列摘要

Free radicals which are the basis for initiating chemical reaction. It has a high chemical reactivity, which can quickly initiate monomer to do polymerization. However, creating the living polymer radical analog living nano-particle (LNP) remains a challenging task. It cannot be stabilized by the steric hindrance and electron resonance. Therefore, we thought of using unimolecular micelles (UM) forming steric hindrance to providing a protecting shell to separate interior living polymer radicals. We use a star-shaped amphiphilic macromolecule which have an amphiphilic arm and POSS core as a nanoreactor. Through the results of dynamic light scattering and small-angle X-ray scattering, it is established that nanoreactor presents a monodispersed spherical model with an average size of 10 nm in water. And then encapsulate the styrene monomer and do nano-confined polymerization to obtain a single living polymer, due to the properties of UM, it will reduce the possibility of radical coupling. The results of 1H-NMR, UV-Vis spectrometer, and GPC exhibit that living nano-particles are successfully created. This creation of LNP is unprecedented and opens a new technique for polymers synthesis using particle initiators.

並列關鍵字

living polymer ； free radical polymerization ； host-guest chemistry ； unimolecular micelle ； polystyrene

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