Polymers fluorene-containing

Aryl-9-substituted fluorenes and 9-substituted fluorene oligomers and polymers Fluorene-containing polymers and compounds useful in the preparation thereof... 

Although effective as electroluminescent polymers, fluorene-containing polymers have limited hole transporting properties because of the tendency of fluor-ene units to aggregate. To impede aggregration Mckieman et al. (3) prepared diindenofluorene monomers, ( ), which were readily processable and had excellent electrical and optical properties. 

Scheme 14 shows the synthetic pathway to copoly(alkylfluorene). Linear, para-linked PDHFPV and kinked meta-linked PDHFMPV show the EL emission at 482 and 426 nm, respectively, corresponding to blue light. Promising results with fluorene contained conjugated polymers offer opportunities for stable blue devices. 

The first synthesis of a soluble and processible poly(2,7-fluorene) was reported by Yoshino and coworkers in 1989 [44,45]. Their approach involved coupling fluorene monomers with substituents at the C9 position by chemical oxidation with FeCls (see P3 in Scheme 1.2). However, the polymerization process was not regiospecific and the polymer backbone contained structural defects that influence the electronic delocalization. Thus, the synthesis of defect-free poly(fluorene)s became a major challenge and advances in carbon-carbon bond forming reactions promoted by organometallic catalysts provided the... 

Fluorene containing polymers exhibit interesting LED properties. These are based on poly[9,9-bis(2 -ethylhexyl)fluorine-2,7-diyl-co-2,5-bis(2-thienyl-l-cyano-vinyl)-l(2 -ethylhexyloxy)-4-methoxybenzene-5",5" -diyl] with strong absorption at... 

Fluorene-containing sulfonated PODAs have been considered for the application as proton exchange membranes for polymer electrolyte membrane fuel cells. The polymers are highly stable thermally and show improved oxidation stability. However, the proton conductivity is around 10 S cm, which is by a factor of 50 lower than that of Nafion membranes. 

Studies [41,47] have demonstrated that polyimides derived from ether-bridged aromatic diamines with -CF3 groups are soluble, high-temperature polymer materials with low moisture absorption, low dielectric constant, high optical transparency, and low birefringence. The effect of fluorene substitution on the dielectric constant of polyimides has been demonstrated for a broad spectrum of fluorene-containing diamine structures (Table 3.2). The... 

C.-P. Yang, S.-H. Hsiao, K.-H. Chen, Organosoluble and ophcally transparent fluorene-containing polyimides based on 4,4 -few(4-amino-2-trifluoromethylphenoxy)-3,3, 5,5 -tetramethylbiphenyl, Polymer 43 (19) (2002)5095-5104. 

The LC property of the fluorene containing polymers, as will be described later, plays a crucial role in improving the charge mobility of the polymers. 

Chen, D. Hickner, M. A. Wang, S. Pan, J. Xiao, M. Meng, Y, Synthesis and characterization of quaternary ammonium functionalized fluorene-containing cardo polymers for potential anion exchange membrane water electrolyzer applications. International Journal of Hydrogen Energy 2012, 37(21), 16168-16176. 

F. Zhu, W. P. Hu and F. L. Zhang, 9-Alkylidene-9H-Fluorene-Containing Polymer for High-Efficiency Polymer Solar Cells, Macromolecules, 2011, 44(19), 7617-7624. 

We have also published a number of papers on photocrosslinkable fluorene containing reactive mesogens and polymers including a series of acrylate functionalized... 

Recently, polyimines include the synthesis of long alkoxy (Cg-Cig) side chain derivatives [188,189], which are presumably soluble to some extent in organic solvents and derivatives containing fluorene cardo unit [190]. Trifluoromethyl groups [191] in the polymer backbone provide solubility in organic solvents. Studies of the electrical conductivity of doped conjugated aromatic polyimines and alkoxy derivatives have been reported [188], and the values are in the range of 10 to 10 S/ cm. 

In the effort to make pure blue-emitting materials Shim and coworkers [146] synthesized a series of PPV-based copolymers containing carbazole (polymers 95 and 96) and fluorene (polymers 97 and 98) units via Wittig polycondensation. The use of trimethylsilyl substituents, instead of alkoxy groups, eliminates the electron donor influence of the latter and leads to chain distortion that bathochromically shifts the emission (Amax = 480 nm for 95 and 495 nm for 97). In addition, a very high PLQY was found for these polymers in the solid state (64 and 81%, respectively). Single-layer PLEDs fabricated with 95 and 97 (ITO/polymer/Al) showed EL efficiencies of 13 and 32 times higher than MEH-PPV, respectively (see also Ref. [147] for synthesis and PLED studies of polymers 99 and 100) (Chart 2.20). 

Similar PPV-based copolymers with carbazole and fluorene units in the backbone 101 and 102 (and also similar copolymers with oxadiazole substituents 103 and 104) have been synthesized by Ree and coworkers [148], Much lower PL efficiency in films was found in this case for carbazole-containing polymers 102 and 104 (1-4%), when compared to materials prepared by Shim (95 and 96, 59-64%) (Chart 2.21). 

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