The route for the preparation of cellulose nanofiber dispersions from bacterial cellulose using ethylene glycol- or glycerol-based deep eutectic solvents (DES) is demonstrated. Choline chloride was used as a hydrogen bond acceptor and the effect of the combined influence of DES treatment and ultrasound on the thermal and mechanical properties of bacterial cellulose nanofibers (BC-NFs) is demonstrated. It was found that the maximal Young’s modulus (9.2 GPa) is achieved for samples prepared using a combination of ethylene glycol-based DES and ultrasound treatment. Samples prepared with glycerol-based DES combined with ultrasound exhibit the maximal strength (132 MPa). Results on the mechanical properties are discussed based on the structural investigations that were performed using FTIR, Raman, WAXD, SEM and AFM measurements, as well as the determination of the degree of polymerization and the density of BC-NF packing during drying with the formation of paper. We propose that the disordering of the BC-NF surface structure along with the preservation of high crystallinity bulk are the key factors leading to the improved mechanical and thermal characteristics of prepared BC-NF-based papers.

Modern materials science, both in terms of functional and structural materials, is actively developing towards the creation of structures with a given ordering. A wide range of methods involves ordering the structure according to a template shape. Template synthesis is one of the mots wide-spread approaches. Most often, the template synthesis method is implemented under conditions of limiting the growth of the phase due to the geometry of the template. In the present work, a template electrochemical method is considered for calcium hydroxyapatite (HAp) coating synthesis, based on the replication of the planar template texture during deposition. In this case, the template is an array of silver microparticles immobilized on an electrically conductive substrate, separated by an insulator layer. The developed approach is similar to the mask metallization widely used in planar technology. In this work, the possibility of the template pulsed electrodeposition of ceramics rather than metal is shown using HAp as an example. This approach is interesting for materials science, in particular, for obtaining micro-ordered hydroxyapatite structures—a crystallochemical analogue of the inorganic bone tissue component—on the surface of bone implants, which can be implemented to improve their biomedical characteristics. As a result of our study, we experimentally determined the conditions for obtaining the composite coating TiO2/Ag/Ca10(PO4)6(OH)2 with controlled phase structure, topology and localization of components on the surface, which was confirmed by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and X-ray Diffraction (SEM, EDS and XRD). The absence of cytotoxicity for the osteoblast-like cells of the developed coating was revealed by cytological tests.