New Conjugated Polymer Materials Containing Triphenylamine: Synthesis, Theoratical , Optical, Electrochemical and Electrochromic Properties

• Main Authors: Han-Yu Wu, 吳翰宇
• Other Authors: Der-jang Liaw
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/81115767255582959155

碩士 === 國立臺灣科技大學 === 化學工程系 === 98 === A novel dibromo compound containing unsymmetrical substituted bi-triarylamine was synthesized. A conjugated polymer was prepared via the Suzuki coupling from the newly prepared dibromo compound and 9,9-dioctylfluorene-2,7-bis (trimethyleneboronate). The glass transition temperature (Tg) of the conjugated polymer was 140 oC, 10% weight-loss temperatures (Td10) in nitrogen was 458 oC, and char yield at 800 oC in nitrogen higher than 64%. Cyclic voltammogram of the polymer film cast onto an indium-tin oxide (ITO)-coated glass substrate exhibited two reversible oxidation redox couples at 0.70 and 1.10 V v.s. Ag/Ag+ in acetonitrile solution. The polymer films revealed excellent stability of electrochromic characteristics, with a color change from yellow green of the neutral form to the dark green and blue of oxidized forms at applied potentials ranging from 0 to 1.3 V. The color switching time and bleaching time were 4.25 s and 7.22 s for 860 nm, and 5.51 s and 6.48 s for 560 nm. A new rapid switching near-IR electrochromic conjugated propeller-shape polymer (PBTPAFL) with lower oxidation potential containing di-triarylamine group was synthesized via Suzuki coupling approach. The observed UV-vis-NIR absorption change in the PBTPAFL film at various potentials are fully reversible associated with strong color changes from original light green to dark green and then to a Prussian blue. Excellent continuous cyclic stability of electrochromic characteristic with rapid color switching time 2.58s and bleaching time 1.76s was found as well. Compared with P1 and P2, the introduction of more electron-donating propyl phenyl group in the para position of PBTPAFL lowered the oxidative potential and prevented coupling reaction during the electrochromic procedure. The high molecular weight conjugated polymer having high thermal stability with Td10 more than 450 oC has excellent solubility in common organic solvents such as NMP, THF, chloroform, toluene, xylene, and benzene at room temperature (25 oC) due to the propeller-shape structure and long alkyl chain on fluorene. Herein, from the combination of the experimental and computational study, we proposed a mechanism based on molecular orbital theory to explain the electrochromic oxidation behavior.