POLY-N-VINYL CARBAZOLE

On the methods of analysis of the thermally stimulated current and the values of the trap depth in poly-N-vinyl-carbazole... 

Another useful commercial polymer is poly N-vinyl carbazole which is of interest in reprographic systems due to its photoactive properties. Here there is competition be-... 

There seems no doubt that organic photoconductor systems will permit the development of new reproduction processes based on the electrophotographic principle 10>. Dyes play an important role in this development on the one hand they act as spectral sensitizers of the organic photoconductors (e.g. poly-N-vinyl-carbazole 161> and on the other hand, the photoelectric effects of dyes are important for... 

Polymeric charge transfer complexes of poly(N-vinyl carbazole) and TCNQ have also been investigated 104). These contained relatively little TCNQ <3 mole %). Consequently little enhancement of conductivity was observed. 

Taniguchi, A., S. Kanda, X. Nogaito, S Kusabayashi, H. Mikawa, and I. Ito The electrical properties of poly(N-vinyl carbazole)/TCNQ polymers. Bull. Chem. Soc., Japan 37, 1386 (1964). 

In the first part of this chapter we review some basic concepts of photoconductivity which are followed by a renew of some experimental techniques and how these have been applied to characterize some of the well known polymeric systems such as poly(N-vinyl carbazole) (PVK) and the charge transfer complex of PVK and 2,4,7,trinitro-9-fluorenone (TNF). The second part of this chapter is a review of the extensive original and patent literature on a variety of photoconducting polymers. 

In general, the polymers with polyconjugated systems of double and triple bonds are photoeonductive in the UV and at least part of the visible range. In some cases the photoresponse extends to the near infrared range. Although their usefulness in practical applications has been many times suggested, the results have been more or less disappointing. The main problems still remain difficult synthesis, in most cases poorly identified structure, and with few exceptions insolubility and intractability of the polymers. The direct comparison with poly(N-vinyl carbazole) and other photoeonductive polymers is not possible for lack of comparative data. 

Cationic polymerizations are not only important commercial processes, but, in some cases, are attractive laboratory techniques for preparing well-defined polymers and copolymers. Polyacetal, poly(tetramethyl-ene glycol), poly(e-caprolactam), polyaziridine, polysiloxanes, as well as butyl rubber, poly(N-vinyl carbazol), polyindenes, and poly(vinyl ether)s are synthesized commercially by cationic polymerizations. Some of these important polymers can only be prepared cationically. Living cationic polymerizations recently have been developed in which polymers with controlled molecular weights and narrow polydispersity can be prepared. 

Silicon-Based Polymer Science A Comprehensive Resource POLY (N-VINYL CARBAZOLE)... 

Fig. 36. Temperature d ndence of emission intensities from excamer sites in poly(N-vinyl carbazole). a = 295, b = 275, c = 260, d = 240. e = 220. f = 200 K...

The behaviour of poly(N-vinyl carbazole) is certainly complex, and an attanpt has been made recently to gain an insight into the photophysical properties of this polymer by studying the related compounds below. Monomer fluorescence is observed in these compounds... 

Roberts, A. J., Phillips, D.. Abdul-RasouL F., Ledwith, A. Temperature dependence of excimer formation and dissodation of poly(N-vinyl carbazole). J.CS. Faraday I. (in press) 1980... 

Sakuratani. Y. Asai. M. Tokita. M. Miyata S. (2001). Enhanced electron injection and electroluminescence in poly(N-vinyl carbazole) film doped with ammonium salt. Synthetic. Metals, vol. 123, no. 2, 207-210. 

Even in the absence of substitution on the a-carbon, extremely large side groups attached directly to the polymer chain, as in poly(N-vinyl carbazole), can cause a large tacticity effect. 

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