Authors:Yusuf Nur, Demet Colak, Ioan Cianga, Yusuf Yagci, and Jale Hacaloglu
High temperature pyrolysis studies of poly(phenylene vinylene)s PPVs with lateral substituents poly(ε-caprolactone) (PPV–PCL)
or poly(ε-caprolactone) and alternating Br (PPV–PCL–Br) or polystyrene (PPV–PSt) clearly showed that thermal stability of
both the substituent and PPV were affected by the thermal stability of the other. In all the polymers under investigation,
decomposition started by the degradation of the substituent. The thermal stability of the PPV backbone increased in the order
PPV–PCL–Br < PPV–PCL < PPV–PSt. When the thermal stability of the substituent was significantly lower than that of the PPV
backbone, as in the case of PPV–PCL and PPV–PCL–Br, then the radicals generated at early stages of pyrolysis coupled before
the temperature reached to the values necessary for complete decomposition. This inturn yielded a thermally more stable crosslinked
structure. The increase in thermal stability was greater upon coupling of the radicals generated on the PPV backbone.
Authors:Y. Nur, D. Colak, I. Cianga, Y. Yagci, and J. Hacaloglu
Thermal degradation characteristics of a new macromonomer polystyrene with central 4,4′-dicarbaldehyde terphenyl moieties
and poly(phenylene vinylene) with well-defined polystyrene (PPV/PSt) as lateral substituents were investigated via direct
pyrolysis mass spectrometry. A slight increase in thermal stability of PSt was detected for (PPV/PSt) and attributed to higher
thermal stability of PPV backbone. It was almost impossible to differentiate products due to the decomposition of PPV backbone
from those produced by degradation of PSt.
Using the pulse-radiolysis time-resolved microwave conductivity technique the mobility and decay kinetics of radiation-induced
charge carriers is studied in a series of poly(2,5-dialkoxy-phenylene vinylene) derivatives. The lower limit to the sum of
the mobilities of the positive and negative charge carriers, Σμmin, depends strongly on the alkoxy functionalization and ranges from 1.2·10−7 to 1.4·10−6 m2/V·s at room temperature. Σμmin increases with the degree of order in the material. The after-pulse conductivity decay kinetics are disperse and are controlled
by a combination of charge recombination and trapping.
Authors:Long Han, Deepak Doraiswamy, and Rakesh K. Gupta
indium-tin oxide (ITO) and the usual cathode materials are Ca, Mg, and Al, or Al.Li alloys. Commonly used LEPs are conjugated polymers like poly (phenylenevinylene), polythiophene, and poly ( p -phenylene). Hole-transport layers like PEDOT-PSS (poly(3