Conjugated polymers morphology

Babel A, Li D., Xia Y, and Jenekhe S.A., Electrospun nanofibers of blends of conjugated polymers Morphology, optical properties, and field-effect transistors, Macromolecules, 2005, 38,4705-4711. 

Rotations around torsional barriers induce changes in chain conformation. For conjugated systems like polydiacetylenes, flow-induced changes in chain conformation can have a profound influence on the photon absorption and electronic conductivity properties of the material [73]. Flow-induced changes in molecular conformation form the basis for several technically important processes, the best known examples are the production of oriented fibers by gel spinning [74], the compatibility enhancement [75] and the shear-induced modification of polymer morphology [76]. 

M. Ariu, D.G. Lidzey, M. Sims, A.J. Cadby, P.A. Lane, and D.D.C. Bradley, The effect of morphology on the temperature-dependent photoluminescence quantum efficiency of the conjugated polymer poly(9,9-dioctylfluorene), J. Phys. Condens. Matter, 14 9975-9986, 2002. 

Schwartz BJ (2003) Conjugated polymers as molecular materials how chain conformation and film morphology influence energy transfer and interchain interactions. Annu Rev Phys Chem 54 141-172... 

Song J, Cheng Q, Kopta S, Stevens RC. Modulating artificial membrane morphology pH-induced chromatic transition and nanostructural transformation of a bolaamphiphilic conjugated polymer from blue helical ribbons to red nanofibers. J Am Chem Soc... 

Although the above mobilities in isolated chains of conjugated polymers and in solid phases are much larger than values inferred from ToF experiments, in no case do they come close to the value of 1,000 cm /V s expected for a perfect onedimensional 7i-bonded polymer chain. Moreover, they are morphology-sensitive. 

Nguyen TQ, Martini IB, Liu J, Schwartz BJ (2000) Controlling interchain interactions in conjugated polymers the effects of chain morphology on exciton-exciton annihilation and aggregation in MEH-PPV films. J Phys Chem B 104 237... 

Pu reported the synthesis of axially chiral-conjugated polymer 82 bearing a chiral binaphthyl moiety in the main chain by the cross-coupling polymerization of chiral bifunctional boronic acid 80 with dibromide 81 (Equation (39)). The polymer is soluble in common organic solvents, such as THE, benzene, toluene, pyridine, chlorobenzene, dichloromethane, chloroform, and 1,2-dichloroethane. The polymer composed of racemic 80 was also synthesized, and the difference of characteristics was examined. Optically active polymer 82 was shown to enhance fluorescence quantum yield up to = 0.8 compared with the racemic 82 ( = 0.5). Morphologies of the optically active and racemic polymers were also compared with a systematic atomic-force microscopy (AEM). 

Most research effort, therefore, concentrated on those polymers where it is possible to control morphology, to obtain chemically pure materials and to manipulate them to provide forms, e.g. chain oriented samples and thin films, suitable for basic research and applications. The development of synthetic routes that provide clean, reproducible samples has been critical in the progress achieved in understanding the physics of conjugated polymers. This in turn underpinned the rapid development of technological applications, which appeared on a much shorter timescale than for other, comparable technologies. The level of scientific and technical interest in polymers, such as PAc, PAni, PPy, PThs, PPVs and polyfluorenes, has resulted in the commercial production of them and their precursors. 

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