Toward the development of new textile/plastic electrochromic cells using triphenylamine-based copolymers

We report the preparation and characterization of new electrochromic polymers containing a 4-butyltriphenylamine (BuTPA) unit on the main chain. All polymers were obtained through the Suzuki-Miyaura cross-coupling reaction between 4-butyl-N,N- bis((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-4-phenyl) aniline) and several aryl dibromide molecules to modulate the electronic properties of the resulting copolymers. 2,5-Dibromothiophene, 2,5-dibromo( 3,4-ethylenedioxythiophene), 3,6-dibromo-N-octylcarbazole, bis(6-bromo-N-octylcarbazol-3-yl), and 2,7-dibromo-3,6-dimethoxy-9,9-dihexylfluorene were used as comonomers and led to five new copolymers, PT( BuTPA), PE( BuTPA), PC( BuTPA), PCC(BuTPA), and PF(BuTPA). These polymers are readily soluble in many common organic solvents, which make them suitable for spray-coating film deposition. Electrochromic cells with the following configuration were assembled: ITO-coated glass or plastic/electrochromic polymer/gel electrolyte/ITO-coated glass or plastic or conducting textile. These copolymers exhibit good optical and electrochemical properties for military camouflage needs with color transition from pale yellow to green, transparent to khaki, or pale green to reddish-brown. Electrochemistry, spectroelectrochemistry, and colorimetric measurements of the devices were examined.