Polystyrene defect groups

To the best of our knowledge, the supercoil conformation of the monoden-dron jacketed polystyrene is one of the first observations of a defined tertiary structure in synthetic polymers. The plectoneme conformation could be caused by underwinding or overwinding of a backbone from its equilibrium state [168]. Quick evaporation of the solvent certainly can cause a residual torsion in the molecule as it contracted in itself. Unlike macroconformations of biomolecules, where the tertiary structures are often stabilized by specific interactions between side groups, the supercoil of the monodendron jacketed polymers is metastable. Eventually, annealing offered a path for the stress relaxation and allowed the structural defects to heal [86]. 

Excimer properties in polymers have special interest in various contexts. Polystyrene prepared by an anionic end-to-end coupling reaction has been found to give anomalous emission between 300-320 nm, attributable to styrenic chain-end impurities. Other workers also associate polystyrene emission with chemical defects in the main chain and optical impurity centres. In the same region 300-350 nm excimer emission is observed, while longer wavelength emission is due to phenylhexatriene groups. Two different time regions of... 

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