This paper proposes to obtain homogeneous and stable blends of oligo(9,9-dioctylfluorene)-co-phenylene (OF), a conjugated oligomer with strong tendency of formation of excimers in the solid state, and nitrile rubber (NBR). This rubber protection reduces the formation of polymer excimers in the films. The fluorene oligomer was synthesized via Suzuki reaction and incorporated in the nitrile rubber. The films were formed by spin coating and casting techniques on the proportions of 1, 5, 10, 20 and 50 % (w/w) of OF in the nitrile rubber (NBR). The structural, optical and thermal properties of the films were evaluated with infrared, UV-Vis, fluorescence and thermogravimetry, respectively. The nitrile rubber proved to be essential for the preparation of homogeneous and stable films, since it was not possible to obtain films with only fluorene using the above-mentioned techniques. Furthermore, luminescent properties of OF are unchanged and the excimers formation in the solid state decrease suggesting the efficiency of nitrile rubber as the matrix for making films.
The copolymer, poly[(9,9-dioctylfluorene)-cothiophene] (PDOF-co-Th), prepared by the Suzuki reaction, was deposited as thin films on ITO substrates using the Langmuir-Blodgett and Langmuir-Schaefer techniques. The optical properties of the films were studied by UV-Vis reflectance, photoluminescence and time-resolved photoluminescence, and the electrical properties by electrochemical impedance spectroscopy as a function of film thickness. Raman spectroscopy and atomic force microscopy (AFM) were also used with the aim of elucidating the interactions between layers and the morphology of the PDOF-co-Th thin films at the interface with the ITO. The absorption and emission spectra showed shifts and alterations in the intensities of the bands as a function of film thickness, related to the formation of aggregates and increases in the radiation selfabsorption effect. The Nyquist and Bode phase diagrams revealed that the charge transfer process at the ITO/PDOFco-Th/electrolyte interfaces was enhanced as the number of layers increased. Raman spectra of monolayer films revealed a preferential interaction between the fluorine rings and the electrode surface that was not strong enough to alter the optical and electrical properties of the copolymer. However, as shown in the AFM images of the PDOF-co-Th film surfaces, there is an increase in roughness and compaction that proves that the material agglomerates as the number of layers increases, suggesting that the thiophene rings also come closer together on the substrate surface, enhancing the charge transfer process at this interface.
The use of blends can be a strategy to obtain new properties or to optimize already existing properties in one of the polymers. In luminescent blends, the presence of a non‐conjugated polymer can maximize its emitting properties. However, the parameters to form this blend are fundamental to obtain homogeneous, translucent and good emission films. The present work analyzed parameters such as solution concentration, solvent, and amount of conjugated polymer, drying time, and drying temperature in order to obtain a luminescent blend. The results showed that these parameters are important in the absorption and emission of the materials, and as little as 5 wt% of the conjugated polymer in the blend allows obtaining an emitting blend with few aggregates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.