Optical and Thermal Stability of Oligofluorene/Rubber Luminescent Blend

Abstract

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.

New Strategy to Prepare Luminescent Blend by Spin Coating

“…In these situations, the emission spectra are wider and shifted to the red region. It noteworthy that, in general, the addition of 20% or more of conjugated polymer in the blend leads to the formation of aggregates . The results showed that the spectrum with 5 wt% of conjugated polymer was the most appropriate to prepare the blends, as it presents the least amount of aggregates for all polymers studied, without losing the definition of maximums obtained.…”

“…It noteworthy that, in general, the addition of 20% or more of conjugated polymer in the blend leads to the formation of aggregates. [15] The results showed that the spectrum with 5 wt% of conjugated polymer was the most appropriate to prepare the blends, as it presents the least amount of aggregates for all polymers studied, without losing the definition of maximums obtained. In previous work, the blend emission for PFPh with NBR (50 wt%) was investigated using a blend prepared by Langmuir-Blodgett (LB) technique.…”

“…The preparation of a blend based on a conjugated and a non‐conjugated polymer can be a good strategy to understand the luminescent properties of the conjugated material without the interference of extern factors, such as the oxidation in the presence of oxygen . Therefore, the nitrile rubber (NBR), which is an elastomer formed by butadiene and acrylonitrile, can be a good example of non‐conjugated polymer since it can behave as a protective and inert material in the polymeric blend, In addition, other elastomers such as styrene‐butadiene (SBR) or polybutadiene (Buna) rubber catalyzed with cobalt (Buna 1203) or lithium (Buna 45B) are compatible materials for a conductive blend.…”

UV-converting blue-emitting polyfluorene-based organic-inorganic hybrids for solid state lighting

“…The constant contribution of this band as a function of the PF indicates that residual fluorenone species are not present [41]. Figure 1(b) shows the composition dependence of the integrated area of the resolved components for each FT-IR component labelled as ( 1), ( 2) and (3) as a function of the % polymer content.…”

Stretchable Fluorescent Polyfluorene/Acrylonitrile Butadiene Rubber Blend Electrospun Fibers through Physical Interaction and Geometrical Confinement

“…A strategy of incorporating elastomers into light‐emitting conjugated polymers not only enhances deformability but avoids aggregation . An acrylonitrile butadiene rubber (NBR), a polar elastomer, has been used to reduce the formation of excimers in polymers for good chemical and high temperature resistance, which is more suitable for optoelectronic device applications than other elastomers (e.g., styrene butadiene rubber (SBR)) . Nevertheless, elastomeric luminescent materials based on polymer blends with good optical properties under high stretch have not been explored in the literature.…”