無機多面體聚矽氧烷團聯式共聚(4-乙基苯酚)高分子之表面能、熱性質及自組裝結構研究

Abstract

本研究製備出一新型帶有多面體聚矽氧(polyhedral oligomeric silsequioxanes, POSS)之2,2,6,6-四甲基哌啶氧化物(2,2,6,6-tetramethylpiperidinooxy, TEMPO)起始劑。以乙醯氧基苯乙烯(acetoxystyrene)為單體，進行氮氧調節自由基聚合反應(nitroxide-mediated radical polymerization, NMRP)及一水解反應去除保護基，合成出無機多面體聚矽氧烷團聯式共聚(4-乙基苯酚)高分子(POSS-poly(4-vinyl phenol), POSS-PVPh)。 在本論文中，我們著重於多面體聚矽氧烷團聯式共聚(4-乙基苯酚)高分子的表面能、熱性質及液態自組裝的研究。我們發現多面體聚矽氧烷的無機核心傾向於分佈在材料表面，造成高分子薄膜的表面能下降，且經過熱處理過後可得到更低的表面能性質。 本論文的另一主題是在探討多面體聚矽氧烷奈米粒子的聚(4-乙基苯酚)或聚(4-乙基苯酚)與聚甲基丙烯酸甲酯(PMMA)混摻系統(POSS-PVPh/PMMA或PVPh/PMMA blends)，利用傅立葉轉換紅外線光譜(FTIR)發現，帶有多面體聚矽氧烷奈米粒子的混摻系統有較低的羰基的氫鍵作用力；然而，在相同的混摻比例下，卻有較高的玻璃轉移溫度，因此我們可以推論多面體聚矽氧烷奈米粒子阻擋了聚(4-乙基苯酚)分子鏈的運動，造成較高的玻璃轉移溫度。 此外我們也發現在末端帶有多面體聚矽氧烷奈米粒子的聚(4-乙基苯酚)團聯式共聚合物在溶液(四氫呋喃/甲苯THF/toluene或乙腈acetonitrile)中呈現非常獨特的自組裝行為；藉由改變四氫呋喃/甲苯的比例或是聚(4-乙基苯酚)高分子鏈段的長度，可以得到不同的型態。

Polyhedral oligomeric silsequioxanes-polyacetoxystyrene (POSS-PAS), a novel inorganic-organic polymer, was synthesized through nitroxide-mediated radical polymerization (NMRP) by using a novel macroinitiator, POSS-2,2,6,6-tetramethylpiperidinooxy (POSS-TEMPO). An amphiphilic block copolymer, POSS-PVPh, was obtained from the hydrolysis of POSS-PAS copolymer. In this dissertation, we focus on the surface free energy, self-assembly in solution and thermal property of POSS-PVPh copolymer. We find that the POSS nanoparticle decrease the surface free energy of POSS-PVPh thin film when it populate on surface and POSS-PVPh polymer thin films possessed extreme low surface free energy after thermal treatment. The miscibility and specific interaction behavior of POSS-PVPh/PMMA was another important subject in this dissertation. From FTIR results, the POSS-PVPh/PMMA blends possess a lower fraction of hydrogen-bonded carbonyl groups relative to those of PVPh/PMMA blends due to the hinder effect of POSS moiety. However, POSS-PVPh/PMMA blends possess higher Tg than that of the PVPh/PMMA blends at the same composition. This phenomenon suggests that the POSS nanoparticle hinder the large-scale segmental motions of the polymer chains and results in higher Tg. For phase behavior in solution, POSS-PVPh copolymer would aggregate in THF/toluene or acetonitrile and self-assembled to well-defined nanostructure. Through changing the composition of THF/toluene mix solution or the length of PVPh segment, the novel morphologies of POSS-PVPh could be observed.