Films of a poly(fluorene-bisthiophene) derivative, named PFBT, were electrodeposited onto indium tin oxide (ITO) electrodes and their electrochromic and fluorescence properties were investigated. Such films displayed color variation from yellow, in the neutral state, to green, in the oxidized state, as shown by tracking of the CIE (Commission Internationale de l’Eclairage) 1931 xy chromaticity coordinates. PFBT films are fluorescent in the neutral state (E = 0.0 V vs. Ag/Ag+) with emission at 532 nm; however, upon oxidation at 0.85 V the photoluminescence intensity is significantly decreased. A solid-state electrochromic device was assembled using PFBT and poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT-PSS) films and a polymer electrolyte. The device presented color variation from transmissive greenish-yellow to blue and reversible fluorescent properties upon switching between -1.5 to 1.5 V vs. PEDOT. Thus, the high contrast and stability both in electrochromism and electrofluorescence of the PFBT film and its device make them suitable for application in multifunctional optical devices.

Hybrid materials based on polyaniline (PAni) were obtained by in situ polymerization of aniline with chitosan and/or organically modified clay (nanomer I-24) in HCl. The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and direct current (DC) electrical conductivity. Thin films of PAni, PAni-clay, PAni-chitosan and PAni-chitosan-clay were prepared by casting a solution of each sample in N-methyl-2-pyrrolidone (NMP) onto indium tin oxide (ITO)/glass electrodes and their electrochromic properties were investigated. It was observed color variation from transparent yellow in the reduced state (E = -0.2 V vs. Ag/AgCl), green in the intermediate state (E = 0.5 V) and dark blue in the oxidized state (E = 0.8 V) for all samples. The color changes of each material in function of the applied potential were tracked using the Commission Internationale de l'Eclairage (CIE) system of colorimetry, in which the color change was much more significant for PAni-clay film.

Filmes fluorescentes baseados em derivados de dansila foram preparados a partir de duas metodologias diferentes. Em uma delas, a superfície de um eletrodo de óxido de índio dopado com estanho (ITO) foi coberta com um filme de quitosana e o polímero foi posteriormente derivatizado com cloreto de dansila, enquanto que na outra metodologia, um filme de dansilglicina foi depositado eletroquimicamente sobre ITO. A técnica de microscopia de força atômica (AFM) foi usada para mapear a superfície dos filmes. A comparação das propriedades eletroquímicas, fotoquímicas e morfológicas destes filmes indicou que o filme de dansilglicina depositado eletroquimicamente sobre ITO apresentou resposta eletroquímica, nível de fluorescência mais intenso, maior rugosidade superficial e maior área superficial relativa em comparação com o seu homólogo quitosana-cloreto de dansila. Esse comportamento pode ser atribuído ao maior número de sítios ativos presentes na estrutura bem organizada do filme eletrodepositado em comparação com os filmes produzidos quimicamente

Dansyl-based fluorescent films were prepared by two different methods. In one of them, the surface of an indium tin oxide (ITO) electrode was coated with a film of chitosan and the polymer subsequently derivatized with dansyl chloride, whilst in the second method a film of dansylglycine was electrochemically deposited on the ITO surface. Atomic force microscopy (AFM) was employed to map the surfaces of the films. Comparison of the morphological, photochemical and electrochemical properties of these films indicated that the dansylglycine film electrodeposited on ITO exhibited electrochemical response, emitted a higher level of fluorescence, presented greater surface roughness and larger relative surface area in comparison with its dansyl chloride-chitosan counterpart. This behavior can be attributed to the higher number of active sites present in the well-organized and rough structure of the electrodeposited film in comparison with the chemically produced films