Structure−Property Relationships in Light-Emitting Polymers: Optical, Electrochemical, and Thermal Studies

A series of new PPV-based alternating copolymers containing conjugated and nonconjugated blocks have been synthesized with the objective of raising the glass transition temperature ( T g ) relative to structures previously obtained. The higher T g was achieved by inserting a more rigid unit in the spacer soft block. The effects of molecular architecture and chromophore substituents on the optical and redox properties of the polymers were investigated. The UV−vis absorption and emission in the solid state were in the range 360−415 and 455−533 nm, respectively. The calculated band gaps using cyclic voltammetry data were in the range 2.41−3.30 eV and were in good agreement with those calculated from the UV−vis spectra edge. The results show that, through a choice of substituents and backbone structure, the emission color and other properties can be systematically varied.