Poly conjugated copolymers

Poly(dithiafulvene)s toward intelligent functional materials have been synthesized [76-78]. An alternating -conjugated copolymer (13) of ferrocene with dithiafulvene showed a unique redox property [76]. Although 13... 

M. Swager, and A. J. Epstein. Exciplex emission from bilayers of poly(vinyl car-bazole) and pyridine based conjugated copolymers./. Chem. Phys., 108(18/7842-7848, 1998. 

The function of barrier in this structure can be attributed either to biphenyl alone (Eg = 4.88 eV 3) or to both biphenyl and azomethine mojeties. Considering the addivity rule for the calculation of the Eg of a conjugated copolymer the contribution of HC=N- mojety is not univocally determined. Bredas has calculated a value of 5.4 eV for the poly(methineimine) but, from a comparison of experimental Eg data of similar polymers - e g. poly(l,4-phenylenevinylene) (PPV) 2.43 eV and (PPI) 2.50 eV a much smaller value of Eg for HC=N mojety can be inferred. 

Andersson and coworkers have prepared solar cells based on blends of poly(2,7-(9-(2 -ethylhexyl)-9-hexyl-fluorene)-fl/t-5,5-(4, 7 -di-2-thienyl-2, l, 3 -benzothiadiazole) (223) and PCBM [416]. The polymer shows a Amax (545 nm) with a broad optical absorption in the visible spectrum and an efficiency of 2.2% has been measured under simulated solar light. The same group has also reported the synthesis of low bandgap polymers 200 (1 = 1.25 eV) and 224 (1 = 1.46 eV) which have been blended with a soluble pyrazolino[70]fiillerene and PCBM, respectively, to form bulk heterojunction solar cells of PCE of 0.7% [417] and 0.9% [418]. Incorporation of an electron-delident silole moiety in a polyfluorene chain affords an alternating conjugated copolymer (225) with an optical bandgap of 2.08 eV. A solar cell based on a mixture 1 4 of 225 and PCBM exhibits 2.01% of PCE [419]. 

Fig. 4 (a) Structural formula of doxOTubicin-conjugated PEG-i>-poly(aspartate) copolymers, (b) The concept of micelle-forming polymeiie drags, as reported in [29]. The optimized formulation of these micelles was the first elinieally tested polymeric micelles (NK911)... 

Jin SH, Jung HH, Hwang CK, Koo DS, Shin WS, Kim YI, Lee JW, Gal YS (2005) High electroluminescent properties of conjugated copolymers from poly[9,9-dioctylfluorenyl-2,7-vinylene]-co-(2-(3-dimethyldodecylsilylphenyl)-l,4-phenylene vinylene)] for Hght-emitting diode appHcations. J Polym Sd A Polym Chem 43 5062-5071... 

Wu, P.-T., Ren, G., Li, C. et al. (2009) Crystalline diblock conjugated copolymers Synthesis, self-assembly, and microphase separation of poly(3-butylthiophene)-f>-poly(3-octylthiophene). Macromolecules, 42,2317-2320. 

Using the same approach, a substituted HT poly thiophene copolymer containing alkyl and w-hydroxyalkyl side chains has been prepared [122]. The w-hydroxyalkyl side chain was first protected with a tetrahydropyranyl (THP) ether, polymerized, and deprotected to give the random copolymer 19 (Fig. 9.34). The copolymer 19 contains a free alcohol at the end of the side chain and can be functionalized by a number of reagents to tailor the properties of the conjugated polymer. 

The polymerization processes described in this chapter may also impart a helical structure in heterocyclic conjugated polymers or aromatic systems that do not have chiral substituents in the side chain. In fact, in recent years various helical conjugated copolymers, such as poly thiophenes, polyethylenedioxythiophenes, and phenylene-thiophene, have been synthesized by electrochemical or chemical polymerization using the N -LC host phase [171-178]. 

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