Applications, polymers redox cycled

Polythiophenes present a multitude of color contrasts. These polymers, with a functional group terminal to a flexible alkyl chain at the 3-position of the ring, are used for many specialized applications. One such candidate of this class is poly(3-[12-(/7-methoxyphenoxy)dodecyl]thiophene [poly(12-MPDDT)], synthesized by Ribeiro et al., which exhibited a deposition charge of ca. 65 mCcm" presented greater stability over a large number of redox cycles (> 1000), a chromatic contrast of 40 % at 725 nm, a Coulombic efficiency of 80 % and good optical memory in the neutral state (E = 0.0 V) [15]. 

Spectroelectrochemical analyses of the BBB, BBL, and PPTZPQ polymer films were performed to study the electronic structure and to examine the spectral changes that occur during redox switching both are inportant for electrochromic applications. BBL spectra showed an increase in absorbance at 524 nm, a decrease at 583 nm, and two not well-defined isosbestic points at 375 and 550 nm BBB spectra did not show clear isosbestic points. For die reduced form of BBB, the maximum peak was at 503 nm, and as die lied potential passed over the first voltammetric feature, the film exhibited an absorption peak at 576 nm These electrochromic effects were stable and reversible under anaerobic and anhydrous conditions die BBL and BBB films continued to exhibit strong color changes after more dian 500 successive cycles in MeCN (24). 

Metallophthalocyanine polymers offer good stability in thermal, chemical, hydrolytic and photochemical environments. The reversible redox property and cycle stability of phthalocyanine compounds and their polymers make them useful as active components in sensors, switches, diodes, memory devices, NLO materials, etc. different types of phthalocyanine polymers are available and they are amenable to chemical modifications to suit the devices requirements. It is possible to exercise chemical control of the properties of the phthalocyanine polymers as well as functionalize other conducting polymers with the characteristics of phthalocyanines. Hence phthalocyanine polymers have become potential candidates for producing useful and viable materials for electronic, optoelectronic and molecular electronic applications. 

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