Electrochromic Characteristics of Substituted Polyanilines

• Main Authors: Chyan, Ching-Haur, 錢經豪
• Other Authors: Wha-Tzong Whang
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/33687034562098318556

碩士 === 國立交通大學 === 材料科學與工程研究所 === 84 === A series of electrochromic polymers were electropolymerized from varioussubstituted anilines with one component or two components. The substitutedanilines included o-anisidine, o- aminobenzotrifluoride, anthranilonitrile,and 2-fluoroaniline. In the cyclic voltammetry(CV) study, poly(o-anisidine)and o- anisidine copolymer had the same electron transfer reaction : (1)withthe formation of semiquinone radical cation (color from pale yellow to green),(2)with the formation of sp2 hybrid in nitrogen atoms by deportonation (colorfrom green to purple- blue).However, the electrochemical parameters, △E1/2, were different for these co-polymers. The values of △E1/2 were 425.5 mV, 442 mV, 465 mV for o-anisidine/ o-aminobenzotrifluoride, o- anisidine / 2-fluoroaniline, and o-anisidine / anthranilonitrile copolymers respectively at a molar ratio of 1/2. The UV- VISspectra for the base form of these polyaniline copolymers also confirmed the order of the feasibility of electrochemical reaction as follows : o-aminobenzo-trifluoride > 2-fluoroaniline > anthranilonitrile.The electrochromic device was composed of an ITO glass as a counter electrode,a polymer electrolyte layer, and a polyaniline copolymer deposited on the otherITO glass as a working electrode. The polymer electrolyte, being made of poly( acrylic acid)( PAA ), chlorine terminated poly(ethylene ether)( PEC ), and PEC/LiClO4 polymer solution, was sandwiched between the two electrodes to form an electrochromic device. It has been observed that the cyclic life of the electro-chromic device increased with the bulk of the substituted groups of the poly- anilines. The cyclic life was of 4500 cycles for o- aminobenzotrifluoride copolymer system longer than that of the 2-fluoroaniline system (around 4000cycles), and the cyclic life of anthranilonitrile copolymer system was of 2000cycles. A longer cyclic life of 5500 cycles for o-anisidine / o- aminobenzotri-fluoride electrochromic system could also be obtained by designing a specialcounter electrode.