ИСТИНА

Both low molecular weight and polymer liquid crystals (LCs) doped with metal and semiconductor nano-particles (NPs) attract the growing attention because the properties of such composites may differ significantly from those of pure soft materials. Some fundamental issues of hybrid organicinorganic composites created via introducing of nanometer scale colloidal particles (NPs) into LC polymer matrices will be discussed. The control of the processes of ordered structure formation in nanocomposites is driven by anisotropic polymer matrixes by means of chemical coupling of polymers with NPs, mesophase structure type and NP shape control. The binding of NPs by polymer macromolecule allows the embedding of NP in a polymer matrix at much higher content with no phase separation than just simple blending. In frameworks of that approach two different models will be discussed, namely, an interaction of functional groups in side chains of polymers responsible for LC formation with the surface of a semiconductor NPs and an attachment of the polymer backbone to the surface of plasmonic NPs: Such matrices may govern the distribution and assembly of NPs that are of wide-ranging interest for both fundamental science and technological applications. Several optical phenomena are detected that result from the coupling of NPs and hydrogen bonded LC polymers in one system, namely: a redshift of the exciton photoluminescence (PL) band of CdSe quantum dots (QDs) in smectic matrix relatively to that of colloidal QDs in solution and a splitting of the excitonic state in CdSe QDs while in smectic matrix which results in the increase of photoinduced optic translucence under the action of powerful laser pulses. Cholesteric matrices provide other effects like a blue shift of QDs PL and polarized PL of QDs that appear due to selective reflection of light of a certain polarization characteristic for a cholesteric matrix. RAFT polymerization followed by the reduction of the end group allows creating polymers with the thiol end group capable of the stabilization of gold plasmonic NPs. Optical properties of composite film are the combination of properties inherent to the cholesteric matrix and NPs. The reason is weak overlap of the spectral position of the stop band of the cholesteric polymer and the absorption bands of NPs. However the major result is that the composite with such a high content of NPs retains cholesteric ordering in combination with the lack of aggregation of the NPs.