In this study, bioactive composite systems based on natural polymers (chitosan and lignin) were prepared in this study. The structural, mechanical, and morphological properties of chitosan-based materials containing various amounts of lignin filler were investigated. The infra-red IR spectroscopy data confirmed the formation of chemical bonds between the components of the obtained composites. The mechanical properties of film samples were studied in air and in physiological solution. It was demonstrated that the breaking elongation values of the obtained film samples in the wet state were higher (150–160%) than the corresponding (average) value of a pure chitosan film (100%). The scanning electron microscopy and atomic force microscopy data demonstrated that the introduction of lignin had caused significant changes in the surface morphology of films. The appearance of a strongly pronounced texture and porosity facilitated cell proliferation on the surface of composites, i.e., the bioactivity of film samples was enhanced with an increasing lignin content in the chitosan matrix.

A new type of polymer–liquid crystal (LC) composite with photovariable dichroism and birefringence is described. Porous stretched polyethylene (PE) films with pores size in the range 50–500 nm were used as polymer matrices. A photochromic cholesteric mixture based on a commercial nematic mixture doped with azobenzene and merocyanine dopants was prepared. Highly birefringent deeply coloured flexible films possessing strong dichroism were obtained by introduction of the photochromic LC mixture into the stretched PE films by capillary forces. UV irradiation leads to E–Z isomerisation of azobenzene‐containing molecules inside the composite films and results in a significant decrease of the dichroism almost down to zero due to isothermal transition from the mesophase to isotropic melt stimulated by the isomerisation process. This process is reversible and the visible light irradiation or annealing lead to a back transition to the uniaxial birefringent and dichroic state. The composite films show a high fatigue resistance during the alternating cycles of the UV–visible irradiation. These novel composites can be considered as promising materials for photonics and optical information processing.