Oligomers, defined length monodisperse

Furthermore, it turned out that the structurally defined and monodisperse oligomers are excellent model compounds for the corresponding polydisperse polymers which include chain length distributions, defects... 

The exactly defined length of such oligomers is due to the monodisperse character of the compounds having an exactly defined number of repeat units n. Moreover, the distance L between the terminal positions of the conjugated system can be described as a linear function of n, provided that conformational effects do not considerably affect the extent of the oligomeric molecules. Scheme 11.2 illustrates L(n) for the series of oligo(l,4-phenyleneethynylene)s (OPE) 1 and oligo(l,4-phenylenevinylene)s (OPV) 2. 

Oligomers are well-defined systems of monodisperse (uniform-length) molecules, with greatly reduced occurrence of defects within the molecular chains, in comparison with polymers. They therefore offer the possibility of better ordering of the molecules and consequently more well-defined optical properties. This renders them particularly appealing for both theoretical and experimental investigations... 

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