This manuscript reports a universal chain-growth polymerization protocol for conjugated polymers. Herein, the Pd-based catalyst moiety dissociates from the growing active center into the solution and therefore, the controlled chaingrowth character is not relying on any specific, system-related complexation, as is the case in polymerization methods reported before. This makes the protocol applicable on a broad range of monomers and, furthermore, also allows an easy onepot synthesis of block-copolymers by successive monomer addition. A chain-growth polymerization mechanism for poly(3-hexylthiophene) (P3HT) and poly(9,9-dioctylfluorene) (PF) and all-conjugated block-copolymers of them is presented. Moreover, the sequence of monomer addition in the synthesis of these conjugated block-copolymers is unimportant, which is unique. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5339-5349, 2011

We investigated by dielectric relaxation spectroscopy the distribution of glass transition temperatures and dielectric relaxation strength inside ultrathin polymer films capped between metallic layers. Measurements of the local dielectric properties were achieved by selectively placing layers of dye-labeled polystyrene at different depth inside films of neat polystyrene of different thickness. We show experimental evidence for an interfacial nature of the deviations from bulk behavior; in particular, the value of the dielectric strength and the glass transition temperature strongly depend on the distance from the solid interface. These peculiar profiles of static and dynamic dielectric properties are discussed in terms of a physical picture based on competition between chain adsorption and packing frustration at different annealing conditions. Such a picture was able to rationalize common features observed in properties of ultrathin films like reduction of the relaxation strength, broadening of the dynamic glass transition process, and finally a shift of the structural relaxation time.

No abstract

2′,3′-d]pyrrole)s (PDTPs) with high molecular weights, good yields, and increased solubility were prepared, and their supramolecular behavior was studied. The polymers differ in their polymerization method (using chemical oxidants, Stille-couplings, or a Yamamoto-type polymerization) and the bulkiness of the side chain. The solubility of the polymer depends on the bulkiness of the side chains employed, while the yield and, to a lesser extent, the molecular weight depend on the polymerization method. In general, Stille-couplings proved to be the best polymerization method for PDTPs. The higher molecular weight polymers showed more defined voltammograms, higher λ max together with the presence of a vibronic fine-structure, and higher fluorescence yields than lower molecular weight materials. In solution, the polymers are present as highly conjugated rigid rods, which, upon transition to films or in nonsolvents, poorly aggregate. The stacking is more complicated in high molecular weight polymers than in low molecular weight samples.

No abstract