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Fourier transform infrared spectroscopy (FTIR) was used for determination of orientational and conformational characteristics of plane polypeptide brushes with different density of polypeptide chains grafted to modified silicon surface. The determination of grafting density of polypeptide chains in brushes, which depends on chemical structure of spacer groups, was carried out using ultraviolet (UV) spectroscopy. The influence of chemical structure of modifying spacer groups and outer conditions on the characteristics of plane polypeptide brushes was established. The peculiarities of α-helical structure (random coil transfer of polymer chains in brushes under the action of denaturants) were investigated.

A comparative analysis of phase transitions in diols with various chain lengths [(CH2)(44)(OH)(2) and (CH2)(22)(OH)(2)] and changes in their absorption spectra with temperature have been investigated by DSC and FTIR. Analysis of the DSC data has led to the conclusion that the low-temperature phase transition of (CH2)22(OH)2 in a solid state (Ts-s = 367.1 K) is a phase transition of the first order, while the high-temperature phase transition (T-m = 376.3 K) is of the second order, i.e., a transition of the order-disorder type. Splitting of the IR absorption bands into doublets at 720-730 cm(-1) and 1463-1473 cm(-1) indicates that crystalline subcells in the lamellae of both diols are orthorhombic lattices with the parameters typical of hydrocarbons. IR spectra showed that at the phase transition temperature Ts-s transformation of an orthorhombic subcell into a hexagonal one occurs. This type of molecular chain packing remains the same up to the melting temperature T-m. In a (CH2)44(OH)2 diol, the ortho-hexagonal subcell transition occurs only at the melting temperature (390.0 K). The wide IR band in the region from 3000 cm(-1) to 3600 cm(-1) shows that end hydroxyl groups of diol molecules form, on the surfaces of lamellar crystals, long (polymer) regular sequences consisting of intermolecular hydrogen bonds.

Conformational transitions in thermotropic main-chain polymers of complex chemical structure including homopolymers with possibility of conformational transformations in mesogens and random copolymers (CPLs) containing mesogens of the same type and spacers of different lengths were investigated. It was demonstrated that liquid crystalline (LC) state influences conformational transformations in fragments of chain restraining them in comparison with an isotropic melt. It was found that CPLs studied form LC order of smectic type. Peculiarities in spacers behaviour during transition to LC state ensure formation of such type of LC order. Conclusion about dependence of mechanism of smectic LC order formation on chemical structure of rigid components of CPLs is made.

Mesogen conformations in thermotropic polyesters with alternating mesogens and poly(methylene) spacers were investigated by IR spectroscopy with polarized and unpolarized light. The selective deuteration of terephthaloyl-bis(p-oxybenzoate) mesogens gave a possibility of assigning part of the IR bands to terephthalic or to oxybenzoic fragments. It is shown that in the liquid crystalline melt the mesogen conformation is planar, but in the semicrystalline state it is mainly nonplanar. Differences in mesogen conformations of polymers containing an even or an odd number of methylene units in the spacer are detected. Thus, LC ordering seems to affect not only the conformation of the spacer but also the conformation of the mesogen.

The conformations of thermotropic polyesters with alternating mesogens and poly(methylene) spacers in the main chain were investigated by conformational calculations using the data of linear-dichroism IR-spectroscopy, X-ray analysis and differential scanning calorimetry. The conformations of monomeric units and of the macromolecules as a whole in different phase-aggregated states were estimated. It is shown that in the liquid-crystalline (LC) state the polymer chains are strongly extended. The results are compared with the data of various theories of LC ordering.