Poly(3-buthyl-co-3,4-dibuthylthiophene)s: synthesis, characterisation and electrochromic properties

Summary form only given. We have prepared a series of soluble, processable copolymers containing both 3-buthylthiophene and 3,4-dibuthylthiophene units in well defined percentages. The modification of the copolymer composition produces materials with various p-electron conjugation length and with diverse electrochromic properties suitable for applications in optical devices. These materials have been characterised by NMR and GPC techniques and by UV-Vis-NIR and FTIR spectroscopies. The copolymers show different absorption maxima of p-p* transition and different energy-gap depending on copolymer composition. The copolymers have been electrochemically p-type doped and their electrochromic performance rated on the base of switching time, cycle life and optical memory will be reported and discussed with a view to the development in variable-light transmission devices.