Photophysics of single chain poly(arylene ethynylene)s

This dissertation presents the results of an investigation into the photophysical properties of single conjugated polymers. The study focuses on the properties of polymers as single-chain "molecular wires" rather than as bulk materials. The dissertation focuses on the design and synthesis of these materials and the use of a variety of techniques to probe their unique properties. The primary focus of the photophysical investigations is the use of optical techniques, although radiolytic techniques were also applied where appropriate.;All of the polymers under investigation were demonstrated to show rapid and efficient transport of singlet, poleron, and triplet carriers. In order to study these properties, polymers with incorporated carrier traps were synthesized. These traps were either randomly distributed throughout the polymer chain or appended to the polymers as end-caps.;Helical, organometallic polymers were also synthesized and investigated. A hydrophobic polymer with ester pendant groups was subjected to post-polymerization functionalization to give a hydrophilic material with pendant acid groups. This polymer has many similarities to DNA in that it is a polyanion that readily adopts a helical conformation characterized by face-to-face stacking of aromatic moieties. This polymer accepts many well-known DNA intercalators which show characteristic spectral changes upon binding. Additionally, binding of the polymer to a chiral guest induces the preferential formation of one of the two possible enantiomeric helices, as evidenced by circular dichroism spectroscopy.