Eletrodeposição de um derivado de bis(tiofeno)-fluoreno (FBT) sobre superfícies condutoras para revelação de impressões digitais latentes

Abstract

In this study was studied the electrochemical and electrochromic properties of films poly(bisthiophene-fluorene) prepared electrochemically and deposited stanless steel surface and ITO. In addition, the potential application of poly(bisthiophene-fluorene) films, obtained on stainless steel surfaces, as a latent fingerprint developer was evaluated. The polymeric films were obtained using electrochemical methods and characterized by electrochemical and optical techniques. The development of fingerprints were obtained in polymeric films with incidence of ultraviolet light (365 nm). During potenciodynamic deposition polymer formation was evidenced by polymer nucleation loop, with galvanostatic electrodeposition an increase in the potential value was observed due to the formation of the radical cation. In galvanostatic method, the difference between the electrodeposition curve profile on stainless steel and on ITO may be related to the nucleation kinetics. In cyclic voltammetry of poly(bisthiophene-fluorene) films deposited by potenciodynamic and galvanostatic methods showed similar profiles, that is, a redox pear with anodic peak potential of (Epa) de 0.8 ± 0.02 V and cathodic peak potential (Epc) of 0.6 ± 0.02 V (Epa). In the spectroelectrochemical characterization, the poly(bisthiophene-fluorene) films deposited by potenciodynamic and galvanostatic methods showed electrochromic behavior when subjected to redox cycles. Fingerprint developments showed fluorescence, high contrast and sharpness on poly(bisthiophene-fluorene) films in both the reduced (0.0 V) and oxidized (0.9 V) states rated on the UK Home Office scale between 3 and 4. The results obtained in this study confirm the feasibility of using poly(bisthiophenefluorene) for the development of electrochromic devices and as a latent fingerprint developer.