Polymers with pendant carbazole groups

Other polymers with pendant carbazole groups... 

Polymers with pendant carbazole groups described in this section are usually prepared either by addition polymerization (most frequently free-radical) or by polymeranalogous reactions. Ogava et al. [216] have reported on the synthesis of a carbazolyl-substituted polymer by polycondensation. By condensing a carbazole-containing bisphenol with phosgene they... 

Modified polymers of PPV with pendant carbazol groups and oxadiazole groups have been prepared by direct polymerization of the respective o(,a-dibromo-p-xylene monomers [103]. 

The synthesis of a series of polyacrylates and methacrylates with pendant carbazole groups has been reported [587]. The polymers were prepared by the reaction of ffl-hydroxyalkylcarbazoles or the corresponding alkoholates with poly(acryloyl chloride) and poly(methacryloyl chloride) (43). GPC, H-NMR, and elemental analysis show that high-molecular weight polymers with an almost quantitative degree of substitution are obtained by this polymer analogous reaction. 

Several poly(a-amino acids) with pendant carbazole groups have been described. Tanikawa et al. [193] reported on the synthesis of poly(y-2-(V-carbazolyl)-ethyl-L-glutamate) (18a) and discussed the photoconductivity of the polymer and its charge-transfer complex with TNF. The photocurrents in (18a) are about one order of magnitude smaller than in PVK at all measured wavelengths. Poly(5 -2-(V-carbazoly-l)ethyl-L-cysteine) [194,195] (18b) a jS-sheet forming polypeptide, was synthesized from the corresponding V-carboxy anhydride. 

Acrylics and Methacrylics. Acrylic and methacrylic polymers with pendant (tricyano-vinyl)carbazole groups [161] or dicyanovinylidene-phenylamine groups [162] have been synthesized. 

The oxadiazole group is already present in 2,2 -(oxydi-4,1 -phenylene)his [5 - (4-fluorophenyl)-1,3,4-oxadiazole], c.f. Figure 10.1. The compound can be condensed with various naphthalenedioles, such as 1,5-naphthalenediol, to result in PODA types [8]. All polymers are amorphous materials and some of them are soluble in aprotic solvents. Alkylated 2,7-dibromo-9H-fluorene compounds, with pendant carbazole and oxadiazole units, can be condensed with nickel catalysts [35,36],... 

Besides polymers with a carbazole moiety a number of polymers with various pendant aromatic amino groups have been reported. Poly(N-vinyldiphenylamine) (17a) and... 

The transport-active groups can be part of the polymer backbone structure, they can be covalently linked as pendant groups to a vinyl or similar chain such as carbazole groups (substituted aromatic amines) in PVK, or need not be covalently attached to the polymer backbone at all. Indeed, solid solutions of NIPC in polycarbonate display hole mobilities that are comparable to those in PVK [19, 20]. The polymer backbone in PVK does not contribute to transport, but merely ties the transport-active groups together. Similarly, both solid solutions of triphenylamine (TPA) in polycarbonate [21] and poly (methacrylate) with pendant triphenylamine groups [22] display photoconductivity and charge transport. 

As demonstrated in previous sections, the carbazole unit was introduced as a pendant group or as a chain member in major classes of EL polymers such as PPVs (95-105,141,177, 190) and PFs (62, 63, 242-245). A variety of 2,7-carbazole-derived polymers with different conjugated units, such as 2-alkoxy- and 2,5-dialkoxy-l,4-phenylene (549) and l,l -binaphtha-lene-6,6 -diyl (550 [658]), 2,5-pyridine (551), 2,7-fluorene (245 [345,346]), 2,5 -bithiophene (554 [345]), 5,8-quinoxaline (552), quinquethiophene-SjS -dioxide (450 [550]), 2,5-thiophene (553), 2,5-furan (555), and acetylene (556 [659]) were reported by Leclerc and coworkers... 

Jt OLYSILOXANES WITH PENDANT SIDE CHAINS are interesting materials from both the theoretical and practical points of view. A number of polysiloxanes with various side chains, such as liquid crystals (i, 2), carbazole groups (3), electron-donor and electron-acceptor groups (4), polystyrene (5), and functional groups (hydroxyl or carboxyl) (6), have been synthesized. Polysiloxanes are known for their useful properties, which include flexibility, heat resistance, water repellence, and biological inertness. These properties, combined with the ease with which a tailored polymer structure can be prepared,... 

A polymer composite with a low glass transition temperature has been described as based on layered photoconductive polymers, namely, poly(p-phenylene terephthalate carbazole)s. " These polymers consist of a rigid backbone of poly(pentylene terephthalate) with pendant oxyalkyl carbazole groups. When the host polymers are mixed with various dopants, the layers are preserved and their layer distance increases, indicating that all the guest molecules are confined to the nanoscale interlayer space. 

Carbazole polymers can be roughly subdivided into polymers that contain the carbazole group as a pendant group and those that have the carbazole group in the backbone. A special variety is a carbazole polymer with conjugated groups. 

Electrochemical doping of insulating polymers has been attempted for polyacetylene, polypyrrole, poly-A/-vinyl carbazole and phthalocyaninato-poly-siloxane. Significantly, Shirota et al. [91] claim to have achieved the first synthesis of electrically conducting poly(vinyl ferrocene) by the method of electrochemical deposition (ECD) [91]. This is based on the insolubilization of doped polymers from a solution of neutral polymers. A typical procedure applied [91] for polyvinyl ferrocene is to dissolve the polymer in dichlorometh-ane and oxidize it anodically with Ag/Ag+ reference electrode under selective conditions. The modified polymer [91] (Fig. 28) is a partially oxidized mixed valence salt containing ferrocene and ferrocenium ion pendant groups with C104 as the counter anion. 

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