Synthesis and Electrochromism of Novel Aromatic Polyimides with Phenoxy and Triphenylamine Units in the Main Chain and Pendent Carbazole Groups
| Autor: | Wan-Lin Li, 李宛霖 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 This thesis investigates the synthesis and characterization of two new carbazole-derived, phenoxy and triphenylamine-containing aromatic diamine monomers, namely 4,4’-bis(4-aminophenoxy)-4’’-(carbazol-9-yl)triphenylamine and 4,4’-bis(4-aminophenoxy)-4’’-(3,6-di-tert-butylcarbazol-9-yl)triphenylamine, and their derived aromatic polyimides. The newly synthesized diamine monomers were respectively reacted with various aromatic tetracarboxylic dianhydrides via a conventional two-step procedure that included a ring-opening polyaddition to form poly(amic acid)s, followed by thermal or chemical cyclodehydration to give polyimides. Most of the polyimides were readily in organic solvents and could be solution-cast into flexible and tough films. All the polyimides had high glass-transition temperatures and good thermal stability. Most of these polymers showed two reversible oxidation redox couples on their cyclic voltammograms. The present polymers exhibited a decreased oxidation potential in comparison with previously reported analogs without the phenoxy unit. Incorporation of bulky tert-butyl groups on the electrochemically active C3 and C6 sites of the pendent carbazole unit led to a greatly enhanced electrochemical stability to the obtained polyimides. The polymer films also revealed excellent electrochromic stability with coloration change from a colorless or pale yellowish neutral state to pale blue as a radical cation and blue when fully oxidized. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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