Synthesis and Properties of Redox-Active Polyimides with 3,5-Bis(trifluoromethyl)- or 3,5-Dimethyl-Substituted Triphenylamine Groups

ABSTRACT

Two series of novel redox-active polyimides 8a–8f and 9a–9f were prepared through a conventional two-step procedure from six commercially available tetracarboxylic dianhydrides with 3,5-bis(trifluoromethyl)-4′,4″-diaminotriphenylamine and 3,5-dimethyl-4′,4″-diaminotriphenylamine, respectively. All the polyimides were amorphous and most of them could afford flexible and tough films with good thermal and mechanical properties. Cyclic voltammograms of the polyimides 9a–9f showed reversible redox waves with half-wave potentials (E_1/2) in the range 1.12−1.25 V versus Ag/AgCl in acetonitrile solution. The polymer films revealed good electrochemical and electrochromic stability, with a color change from neutral pale yellowish to blue doped form at applied potentials ranging from 0 to 1.70 V.

GRAPHICAL ABSTRACT

KEYWORDS:

• Electrochemistry
• electrochromism
• polyimides
• redox polymers
• triphenylamine