Síntese e caracterização do polímero de coordenação [Eu2(BDC)3(H2O)4]n em nanoescala e seu potencial uso na revelação de impressões digitais latentes e tintas fluorescentes

Abstract

The study of nanomaterials based on lanthanide ions has been widely highlighted in recent years because of their applications versatility in several scientific and technological areas, such as forensic sciences. Given the above, the purpose of this work is to synthesize via sonochemical crystallization at room temperature the coordination polymer [Eu2(BDC)3(H2O)4]n on nanoscale using the passivating agents polyvinylpyrrolidone (PVP), cetrimonium bromide (CTAB) and polyethylene glycol (PEG) for use in the development of latent fingerprints and fluorescent inks. The EuBDC samples with the different passivating agents showed an isomorphic structure to that exposed by the crystallographic data reported in the literature, indicating that there were no changes in the crystalline phase, together with the results obtained from photoluminescence, which were shown to be similar in all analyzed samples, which was evidenced by the analysis of the characteristic f-f transitions for the Eu3+ ion and π → π* bands of the ligand. The thermal analysis of the samples revealed the influence of the passivating agents on the thermal stability of the material, where it is evident that the increase in their concentrations significantly decreases the temperature required to decompose EuBDC. The morphological properties of EuBDC were also evaluated, and it was possible to observe crystals in the form of plaques and clusters similar to flowers for the samples passivated with PEG. In addition, a decrease in the size of the crystals was observed with the increase in the passivant concentration, in particular, the nanomatization of the MOF EuBDCPVP50 was confirmed, which presented spherical nanoparticles with an average size of 4.6nm. Furthermore, EuBDC acted as an excellent agent in revealing latent fingerprints, making it possible to observe minutiae and subpatterns in them. The use of EuBDC as a fluorescent ink was also efficient, since the ink proved to be suitable for use on different types of paper, and showed high luminescence under UV light. Finally, the synthesis of EuBDC at the nanoscale combined with its photophysical properties has shown to be promising for use in forensics, as well as allowing its application in the biological area.