Comparative studies on Langmuir-Schaefer films of polyanilines

Langmuir isotherms of polyaniline (PANI), poly(o-toluidine) (POT), poly(o-a nisidine) (POAS) and poly(o-ethoxy aniline) (PEOA) were investigated at aqu eous subphase of pH 1, where doping during monolayer formation appeared as an essential step for high quality of the film. The effect of substituent g roups in polyanilines plays a prominent role for the formation of Langmuir films. The area per unit repeat molecule was shown to increase by an increm ent of the substituent groups in polyanilines. Ultra-thin films of PAM, POT , POAS and PEOA were engineered by Langmuir-Schaefer (LS) technique. The un iformity of the deposited polyanilines LS films was verified by atomic forc e microscopy (AFM). The electrochemical properties of polyanilines LS films were investigated by cyclic voltammetry and current transient measurements , and the electrical characteristics were investigated by depositing the fi lms on interdigitated electrodes. The electrochromic switching response tim e and diffusion coefficient of such LS films were also estimated by electro chemical surveyings. (C) 1999 Elsevier Science S.A. All rights reserved.