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The state diagram of the low-density polyethylene–p-xylene system that contains the solubility curve of p-xylene in the polymer is first built using the optical method with the involvement of the DSC data. It has been shown that, at 72°C, in a blend with a polymer mass fraction of 0.28, the full amorphization of the polymer proceeds simultaneously with the dissolution of p-xylene in it. Blends with a lower polymer content are also homogenized at the same temperature, although the duration of this process can take several days. In blends with a high polymer content, homogenization occurs at a higher temperature. This process is preceded by the formation of microheterogeneous single-phase gel with network junctions as polymer crystallites and amorphous regions saturated by p-xylene. Cooling of the homogeneous blends to–20°С is not accompanied by the full separation of low- and high-molecular-mass phases; in this case p-xylene not only forms an individual crystalline phase, but also partially crystallizes in amorphous regions of the polymer.

The role of specific interactions between a polymer matrix and incorporated quantum dots is one of the critical problems for understanding the effect of the polymer matrix on the optical properties of quantum dots in a nanocomposite material and for creating new photonic materials and related instruments. In this study, cadmium selenide quantum dots have been incorporated into a liquid-crystalline polymer via the interaction of carboxyl groups of the polymer with the quantum-dot surfaces through ionic bonds. From the data of transmission electron microscopy, it has been shown that this interaction provides the localization of quantum dots in the environment of the liquid-crystalline phase of the polymer. Various features of photoluminescent properties have been observed and interpreted in terms of the emission recombination of excitons in CdSe quantum dots, light reabsorption by quantum dots, the effect of the electronic states on the surface CdSe-liquid crystal, and the energy transfer from quantum dots to the polymer liquid-crystalline matrix.

On the basis of copolymers of 4-methoxyphenyl-4-(6-(acryloyloxyhexyloxy)benzoate with 4-(6-acryloyloxyhexyloxy)benzoic acid, nonequilibrium composites containing nanoparticles (quantum dots) of cadmium selenide at concentrations many times higher than their solubility limit in the liquid-crystalline phase are synthesized. In the resulting material, the polymer matrix undergoes the transition to the liquidcrystalline state before separation into phases with concentrations of nanoparticles corresponding to thermodynamically equilibrium values. Under common conditions, the composites are stable for at least several months.

A comparative study of the viscoelastic properties of melts of vinyl acetate-vinyl alcohol copolymers with equimolar compositions characterized by different statistical distributions of chain units has been performed. It has been shown that the principle of temperature-frequency superposition is obeyed by copolymers close to a random copolymer, but is violated by copolymers with the block distribution of units. Unlike amorphous random copolymers, a multiblock copolymer is characterized by weak crystallinity, the absence of the relaxation flow state, and a more pronounced tendency to form interchain hydrogen bonds both between two hydroxyl groups and between hydroxyl and ester groups.

A new luminescent composite based on quantum dots of CdSe immobilized on the polymer LC matrix prepared through the graft polymerization of the monomer of 4-(ω-acryloyloxyhexyloxy)benzoic acid on a fluorocarbon support after its preliminary irradiation with vacuum ultraviolet light is elaborated. The structure, composition, and optical characteristics of the prepared composite are studied via the methods of the FTIR spectroscopy, energy-dispersive and wave-dispersive analyses, and luminescence spectroscopy. The CdSe particles are shown to interact with the carboxyl groups of mesogenic fragments of the LC polymer, and this interaction leads to the integration of quantum dots into the ordered LC structure of the composite. As a result of immobilization, the luminescence peak of the quantum dots is shifted toward lower wavelengths owing to the interaction between the nanoparticles and the polymer LC matrix.

This paper briefly summarizes the state of the art in the field of designing composites containing semiconductor nanoparticles distributed in a polymer matrix. Special attention is focused on (i) nanocomposites based on block copolymers and (ii) LC polymer matrices capable of controlling the localization and alignment of nanoparticles.