Synthesis and Characterization of a Novel Electrochromic Aromatic Polyamide from AB-Type Triphenylamine-Based Monomer

A new triphenylamine-based polyamide I was prepared by direct polycondensation of AB-type monomer, 4-amino-4'-carboxy-4"-methoxytriphenylamine (4), in the presence of triphenyl phosphite and pyridine as condensation agents. The obtained polyamide I showed excellent solubility in aprotic polar solvents such as NMP, DMAc, DMF, and DMSO and could be cast into transparent film with weight-average molecular weight (M-w = 63,400) and polydispersity index (PDI = 1.79). The polyamide I exhibited good thermal stability with relatively high glass-transition temperature (282 degrees C), 10% weight-loss temperature above 470 degrees C under a nitrogen atmosphere, and char yield at 800 degrees C in nitrogen higher than 64%. It also showed maximum ultraviolet-visible absorption at 362 nm and exhibited fluorescence emission maxima at 493 nm in NMP solution with fluorescence quantum yield 4.4%. Cyclic voltammogram of polyamide I film cast onto an indium tin oxide coated glass substrate exhibited one oxidative redox couple at 0.72 V (oxidation onset potential) versus Ag/AgCl in acetonitrile solution and revealed good stability of the electrochromic characteristic with a color change from colorless to green at applied potentials ranging from 0.00 to 1.10 V. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47:1988-2001,2009