International audienceThis work presents a simple method to generate ordered conjugated polymer nanoarrays through a pore-filling process for nanoporous polymer templates so as to enhance the efficiency of photoluminescence (PL). PL results combined with the morphological evolution examined by scanning probe microscopy revealed that the enhanced PL reaches maximum intensity as the template pores are completely filled by conjugated polymers. Polarized PL spectroscopy and grazing incidence Fourier transform infrared spectroscopy were used to determine the chain orientation of templated conjugated polymer; the spectroscopic results indicate a parallel chain orientation along the cylindrical direction of nanopores. The induced alignment of the polymer chains is attributed to a nanoscale spatial effect that increases the PL intensity and the lifetime of the conjugated polymer. The enhanced luminescence of nanostructured conjugated polymers is highly promising for use in designing luminescent nanodevices

Four laterally difluorinated phenyl tolane liquid crystals were synthesised and their physical properties evaluated. These compounds exhibit a fairly small heat fusion enthalpy (ÁH , 12.56 kJ mol -1 ), which is favourable for mixture formulations. For comparison, four lateral difluoro cyclohexane tolane homologues are also studied. We doped 10 wt% of each compound into a commercial negative mixture N1 and measured the birefringence, visco-elastic coefficient and figure of merit. Birefringence varies very little between homologues, but the visco-elastic coefficient increases as alkyl chain length increases. The refractive indices of these guest-host mixtures at 1550 nm are also measured.

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Four series of high birefringence biphenyl tolane liquid crystals having a terminal isothiocyanato or fluoro group were synthesized; their mesomorphic properties were studied by optical polarizing microscopy and DSC. These biphenyl tolane compounds exhibit reasonably low melting points and high birefringence of 0.37-0.49. By using these compounds a eutectic mixture was formulated exhibiting a wide nematic range, high figure-of-merit and low viscosity.