Ηλεκτροχημική μελέτη φωτοευαίσθητων ενώσεων και εφαρμογές αυτών στους χημικούς δείκτες υπεριώδους ακτινοβολίας

Abstract

The aim of the present thesis was the electrochemical study of photosensitive compounds and the fabrication of chemical dosimeters for ultraviolet protection. For this specific reason both sodium nitroprusside, a photosensitive compound and some photochromic spiropyrans with different substitutents in their benzopyram moiety were studied by means of the electrochemical technique of cyclic voltammetry. Polyacrylonitrile-based carbon fibers were used as working electrodes in all cases. The electrochemical behavior of sodium nitroprusside was examined in aqueous buffered solutions in pH range between 1.0 and 12.0. The cyclic voltammetric behavior of the spiropyrans was studied in solutions containing acetonitrile or dimethylformamide. From the obtained cyclic voltammograms we proposed satisfactory mechanism for their redox behavior on carbon fiber electrodes. Afterwards we fabricated chemical dosimeters from the dispersion of the photochromic spiropyrans into polystyrene, polycaprolactone and polycaprolactone-polyethylene succinates blends. The photochromic films were illuminated with ultraviolet light for different time periods in the presence and absence of an ultraviolet absorber and an antioxidant compound. The photochromic response of the polycaprolactone-polyethylene succinates blends revealed unexceptionable repeatability to fatigue.