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Thiophene-based conjugated polymers are important conjugated polymers due to their exceptional optical and conductive properties, over the past few decades many researchers have designed novel strategies to reach more efficient materials for electronic applications.

A thermodynamic analysis of phase equilibria in polydisperse polymer−liquid crystal blends is presented. Three different systems were analyzed:  (a) a high molar mass polydisperse polystyrene (PS) blended with 4-cyano-4‘-n-heptylbiphenyl (7CB), (b) a low molar mass polydisperse PS blended with 7CB, and (c) an epoxy-based thermosetting polymer blended with a mixture of small mesogenic molecules usually called E7. In the latter case the analysis was performed in both pregel and postgel stages. Macroscopic phase separation taking into account the fractionation of the polydisperse polymer among different phases, was simulated when cooling from an initially homogeneous state. Predicted isotropic−isotropic and isotropic−nematic transitions showed a good agreement with experimental results. The relative volume fraction and compositions of isotropic and nematic phases were predicted. A temperature range was found where three macroscopic phases, two isotropic and one nematic, coexisted at equilibrium. This was the result of a liquid−liquid (or gel−liquid) phase separation preceding the appearance of a nematic phase. Implications of this behavior on morphologies developed in polymer-dispersed liquid crystals (PDLC) are discussed.

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This paper presents the synthesis and thermal and mechanical properties of epoxy-titania composites. First, submicron titania particles are prepared via surfactant-free sol-gel method using TiCl4 as precursor. These particles are subsequently used as inorganic fillers (or reinforcement) for thermally cured epoxy polymers. Epoxy-titania composites are prepared via mechanical mixing of titania particles with liquid epoxy resin and subsequently curing the mixture with an aliphatic diamine. The amount of titania particles integrated into epoxy matrix is varied between 2.5 and 10.0 wt.% to investigate the effect of sub-micron titania particles on thermal and mechanical properties of epoxy-titania composites. These composites are characterized by X-ray photoelectron (XPS) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric (TG), and mechanical analyses. It is found that sub-micron titania particles significantly enhance the glass transition temperature (>6.7%), thermal oxidative stability (>12.0%), tensile strength (>21.8%), and Young's modulus (>16.8%) of epoxy polymers. Epoxy-titania composites with 5.0 wt.% sub-micron titania particles perform best at elevated temperatures as well as under high stress.