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Abstract Polymer-coated metals may act as biodegradable orthopedic implants with adjustable corrosion rates. Metallic surfaces represent a dynamic system with specific interactions occurring after the material is implanted into the human body. An additional layer, in the form of polymeric thin film, changes the nature of this metal-body fluids interface. Moreover, the interaction between polymer and metal itself can differ for various systems. Iron-based material modified with a thin layer of polyethyleneimine (PEI) coating was prepared and studied as potential absorbable implant. Computational methods were employed to study the interaction between the metallic surface and polymer functional monomer units at atomic levels. Various spectroscopical and optical methods (SEM, AFM, Confocal, and Raman spectroscopy) were also used to characterize prepared material. Electrochemical measurements have been chosen to study the polymer adsorption process onto the iron surface and corrosion behavior which is greatly influenced by the PEI presence. The adsorption mechanism of PEI onto iron was proposed alongside the evaluation of Fe and Fe-PEI degradation behavior studied using the impedance method. Bonding via amino -NH2 group of PEI onto Fe and enhanced corrosion rate of coated samples were observed and confirmed.

This contribution describes the preparation, coupled with detailed characterization, of Nb2O5 nanofibers and their application in lithium–sulfur batteries for the improvement of electrochemical performance. The utilization of reactive needle-less electrospinning allowed us to obtain, in a single step, amorphous pre-ceramic composite PAN/Nb2O5 fibers, which were transformed into porous ceramic Nb2O5 nanofibers via calcination. Thermogravimetric studies defined that calcination at 600 °C results in crystalline ceramic fibers without carbon residues. The fibrous morphology and mean diameter (614 ± 100 nm) of the ceramic nanofibers were analyzed via scanning and transmission electron microscopy. A surface area of 7.472 m2/g was determined through nitrogen adsorption measurements, while a combination of X-ray diffraction and Raman spectroscopy was used to show the crystallinity and composition of the fibers after calcination—single T-phase Nb2O5. Its performance in the cathode of lithium–sulfur batteries was defined through electrochemical tests, and the obtained results were compared to a similar blank electrode. The initial discharge capacity of 0.5 C reached a value of 570 mAh∙g−1, while the reversible capacity of 406 mAh∙g−1 was retained after 200 cycles, representing a capacity retention of 71.3%. The presence of Nb2O5 nanofibers in the carbon cathode inhibits the shuttle effect through polysulphide confinement, which originates from porosity and chemical trapping.

Lanthanide Metal–Organic Frameworks (LnMOFs), in recent years, have developed into an interesting subclass of MOFs. While the number of published papers, in particular, were dedicated to their synthesis and functional properties, along with the application mechanisms of MOFs, only a few of them have been focused on LnMOFs thin films independently. LnMOFs have become interesting thanks to their outstanding properties, for example, excellent structural flexibility, tunable pore size, surface area, functionality, and good chemical stability. Significant progress over the past two decades in the preparation of MOF films has been achieved, especially towards the development of green, or at least greener, synthesis approaches. We begin with insight into various types of MOFs and summarize recent achievements in the production of LnMOF films, along with various film preparation approaches. Afterward, we briefly discuss the applications of luminescence features of lanthanide ions in films and their potential as white-light source materials. We also covered films based on Eu, Tb, and Gd with particular accents on different design approaches. Moreover, specifically, luminescent features applied for sensing temperature, a variety of ions, gases, and biomolecules are highlighted. The review ends with a comprehensive conclusion about the state-of-art-potential of LnMOFs together with an outlook on the future of LnMOF films in future technologies.

The present study is focused on the synthesis and structural properties of amorphous terbium metal–organic framework thin film (TbMOF-TF) and its transformation to terbium oxide by pyrolysis at 450 °C in the air. The crystalline (cTbMOF) and amorphous (aTbMOF) films were prepared by solvothermal synthesis using different amounts (0.4 and 0.7 mmol) of the modulator (sodium acetate), respectively. The powders were characterized by differential scanning calorimetry (DSC), thermogravimetry (TG), Fourier transform infrared (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). The varied chemical composition of the surface of TbMOFs and TbxOy was investigated by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed that aTbMOF had been fully transformed to a Tb4O7 phase with a cubic crystal structure at 450 °C. The amorphous aTbMOF-TF film was prepared by dropping a colloidal solution of amorphous precursor nanocrystals on the SiO2/Si substrates covered with Pt as an interlayer. XPS confirmed the presence of Tb in two states, Tb3+ and Tb4+. The amorphous film has a rough, porous microstructure and is composed of large clusters of worm-like particles, while terbium oxide film consists of fine crystallites of cubic fluorite cF-TbOx, c-Tb4O7, and c-Tb2O3 phases. The surface topography was investigated by a combination of confocal (CM) and atomic force microscopy (AFM). The amorphous film is porous and rough, which is contrast to the crystalline terbium oxide film.