[3]-Radialene-based dopant CN6-CP studied herein, with its reduction potential of +0.8 versus Fc/Fc+ and the lowest unoccupied molecular orbital level of -5.87 eV, is the strongest molecular p-dopant reported in the open literature, so far. The efficient p-doping of the donor-acceptor dithienyl-diketopyrrolopyrrole-based copolymer having the highest unoccupied molecular orbital level of -5.49 eV is achieved. The doped films exhibit electrical conductivities up to 70 S cm(-1) .

Hierarchical ordering in a series of side-group liquid-crystal block copolymers was investigated in the bulk via differential scanning calorimetry (DSC), polarized light microscopy, smallangle X-ray scattering (SAXS), and small-angle neutron scattering (SANS). The diblock copolymers comprise a polystyrene block and a block of poly(methyl methacrylate) bearing a chiral biphenyl ester mesogenic unit linked to the backbone by a dodecyloxy spacer. A series of copolymers with different volume fractions of mesogenic block were prepared by atom transfer radical polymerization. Ordering of mesogens into a smectic phase is characterized by a period 3.5 nm. Glass transition temperatures and the clearing temperature for each sample were determined by DSC. Additional ordering occurs due to microphase separation of the block copolymer at a length scale of 22-27 nm, as confirmed by SAXS and SANS. The order-disorder transition was found to be coincident with the smectic-isotropic transition for a sample comprising PS cylinders. A hexagonal morphology was determined for samples with both a minority and a majority liquid-crystal block. Remarkably, the morphology comprising liquid-crystal (LC) cylinders in a polystyrene matrix could be oriented by slow cooling through the clearing temperature, in the presence of a strong magnetic field. The inverse morphology of cylinders formed by the PS block in an LC matrix was not oriented in this way. This is ascribed to the nucleation of defects around the nanorods in the LC matrix. The thin film nanostructure was investigated by atomic force microscopy (AFM) and X-ray reflectivity for a sample comprising PS cylinders. AFM confirmed a hexagonal-packed cylinder morphology in thin films with coexisting parallel and perpendicular orientations of rods with respect to the substrate. The presence of Bragg peaks in specular X-ray reflectivity intensity profiles indicates a proportion of smectic layers lying parallel to the substrate, with a spacing similar to that in bulk. Our results provide a comprehensive picture of hierarchical ordering in the bulk and in thin films.

It is known that the determination of the equilibrium melting temperatures of polymers which show recrystallization during heating is a difficult problem. This is mainly due to the difficulty encountered in determining the melting temperature of the initial lamellae which exist before recrystallization takes place. We are reporting here the results of a study investigating this problem for a representative polymer, namely isotactic polystyrene. Both the crystallization line and the Gibbs-Thomson melting line were constructed on the basis of time-and temperature-dependent SAXS measurements, respectively. When the two lines are plotted on the same graph, they intersect each other at a finite crystal thickness and at temperature of about 243 °C. This temperature is very close to the commonly reported values of the equilibrium melting temperature of isotactic polystyrene obtained using the Hoffman-Weeks extrapolative method, namely 242 °C. However, the value obtained from the intercept of the Gibbs-Thomson melting line is found to lie in the range of 289 ( 5 °C. This new, higher value of the equilibrium melting temperature of isotactic polystyrene might justify the high melting temperatures found for some isotactic polystyrene samples, which were as high as 255 °C for samples with a shish kebab morphology. Finally, DSC curves were recorded for samples crystallized at different crystallization temperatures in order to compare the Gibbs-Thomson melting line obtained by the SAXS measurements and that obtained by the DSC curves. The result of such comparison showed a good agreement.

The role of anchoring the mesogenic side chains at the internal and boundary interfaces in the thin film morphology has been investigated for two fluorinated side-chain liquid crystalline/amorphous diblock copolymers. Initial bulk investigations indicate that the two polymers strongly microphase segregate into a cylindrical and a lamellar morphology, respectively. Inside the liquid-crystal block, the cylinder-forming block copolymer shows both a crystalline-B and a smectic-A phase, whereas the lamellaeforming polymer gives only a smectic-A phase, with the side chains organized in double layers with a spacing of 3.33 nm. In both situations the smectic layers are oriented perpendicular to the block interfaces, which state is retained in films. In thin films of the cylinder-forming block copolymer, the smectic layering and the orientational wetting properties of the fluorinated side chains stabilize the minority cylindrical domains normal to the substrate. For films of the lamellar system, however, an evolved structure forms with block lamellae parallel to the substrate in combination with anchoring of the fluorinated chains at the surface of the film.