Optical Properties of an Electrochromic Device Based on Poly (aniline 2-sulfonic) acid (PASA) Film, Formed by Ionically Self-Assembled Multilayers (ISAM) Technique

A new ElectroChromic Device (ECD) was designed and constructed based on Ionically Self Assembled Multilayers (ISAM) technique, in which oppositely charged polymers are used to construct films of multiple layers.The ECD device proposed and studied in this work was based on Poly (aniline 2-sulfonic) acid, (PASA), as the active electrochromic polyanion, and Poly (allylamine hydochloride), (PAH), as the inactive polycation.Cyclic Voltammetry (CV) technique was employed to study redox properties of the polymer film and to help to determine the operating voltage of the device.It was determined that the PAH/PASA ECD has two redox states between –700mV and +700mV.The ECD with 40 bilayers demonstrated dark green to light brown to dark gray electrochromism, in the –700mV to +700mV window.The major transmittance occurred at –600mV (dark green) and +600mV (dark gray).The ECD in the relaxed state, i.e. no voltage applied, is light brown.At –600mV, in visible spectrum, the highest contrast (∆T=27%) appeared at approximately 690nm (dark green) and at +600mV the highest transmittance in visible range was a broad range between approximately 600nm to 710nm.