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.

The past two decades have been marked by an increased interest in the synthesis and the properties of geoinspired hydrosilicate nanoscrolls and nanotubes. The present review considers three main representatives of this group: halloysite, imogolite and chrysotile. These hydrosilicates have the ability of spontaneous curling (scrolling) due to a number of crystal structure features, including the size and chemical composition differences between the sheets, (or the void in the gibbsite sheet and SiO₂ tetrahedron, in the case of imogolite). Mineral nanoscrolls and nanotubes consist of the most abundant elements, like magnesium, aluminium and silicon, accompanied by uncontrollable amounts of impurities (other elements and phases), which hinder their high technology applications. The development of a synthetic approach makes it possible to not only to overcome the purity issues, but also to enhance the chemical composition of the nanotubular particles by controllable cation doping. The first part of the review covers some principles of the cation doping approach and proposes joint criteria for the semiquantitative prediction of morphological changes that occur. The second part focuses on some doping-related properties and applications, such as morphological control, uptake and release, magnetic and mechanical properties, and catalysis.

The polymer-inorganic nanocomposites based on the aromatic polyamidoimides and the silicate nanotubes of chrysotile structure were developed. The polyamidoimides were synthesized from...

The growth of nanotubes of the Mg₃Si₂O₅(OH)₄ composition with a chrysotile structure has been investigated under hydrothermal conditions. It has been established that the nanotubes in the axial and radial directions grow through the step mechanism due to the recrystallization and mass transfer of the components. The introduction of seeds considerably promotes the growth process, especially at the nanotube ends. The evolution of chrysotile nanotubes with a variation in different physicochemical parameters of synthesis, such as the temperature, time, NaOH concentration in the reaction medium, and introduction of seeds, has been traced. It has been demonstrated that the controllable variation in these parameters makes it possible to perform a controlled hydrothermal synthesis of chrysotile nanotubes with specified lengths and aspect ratios.