Cristal líquido iônico dimérico não simétrico com propriedades luminescentes

Abstract

With increasing in consumption and manufacturing of electronic devices, there has been a growing interest in the production of materials that are cheaper, easier to synthesize and with reduced power consumption compared to conventional devices. Thus, the research area of organic electronics has been developing and gaining evidence, providing new discoveries and consequently new technological advances, such as, for example, the production of organic light-emitting diodes (OLED), organic field effect transistors (OFET's) and organic photovoltaic devices (OPV's). In the production of these and other materials, Liquid Crystals (CLs) have presented several advantages due to their unique and exceptional properties that combine molecular organization and fluidity. In order to study the properties of non-symmetric dimeric ionic liquid crystals, whose nomenclature was Oxa-C3, this work aimed to synthesize and characterize a new molecule derived from the 1,3,4-0xadiazole heterocycle, where only one mesogenic group will present charges. For the synthesis of the final molecule, the oxapiridine and oxaphenol intermediates were connected through an o,w-dibromoalkane and, after purification by silica gel column chromatography, the compound had its structure and purity analyzed by 1H NMR technique. The thermal properties of the material were analyzed by polarized light optical microscopy (MOLP) technique, in which the formation of the oily streaks texture were observed in the heating and the fan-shapped texture in the cooling of the sample, and it was possible to conclude that the compound has properties liquid crystals with mesophase formation of type smectic A; differential scanning calorimetry (DSC), which was performed with the objective of obtaining values of phase transition temperatures and the energies involved in the processes; thermogravimetric analysis (TGA) which demonstrated that the compound had thermal decomposition at a temperature close to its isotropic temperature; and the small angle X-ray scattering (SAXS) technique, in which it was possible to obtain information regarding the organization of the mesogens in the layers during the mesophase, whose values showed that interdigitation of the terminal alkyl chains of the molecule occurs. UV-vis spectroscopy and fluorescence analysis were performed for photophysical studies, in which the compound showed two absorption bands in the ultraviolet region and two emission bands, one in the ultraviolet region and other in the visible region.