Introduction

Bioactive glasses are a type of biomaterial widely used when high osteoconductive or osteosynthesis capabilities are required. In recent years, research on bioactive glasses has been partially directed towards obtaining more stable compositions with increased network connectivity. Thus, it is possible to use this biomaterial in diverse applications with high surface/volume ratios, such as scaffolds, in which the most reactive bioactive glasses experience excessively rapid dissolution. The micro-structuring of the surface of these biomaterials is a research niche that has been scarcely explored, mainly because the osteoconductivity mechanism that occurs during the interaction with biological fluids is associated with the dissolution of the glass surface layer. However, it has recently been shown that surface modification by laser can produce permanent long-term surface changes.

Methods

For this work, recent reports in the field of laser surface modification of bioactive glass have been critically studied and analysed. In addition, laboratory experiments have been carried out on the structuring of the surface of glasses with different network connectivities. The in vitro behaviour when in contact with simulated physiological fluid has been characterised.

Results and conclusions

In this work, the latest advances in laser surface modification of bioactive glasses are presented, discussing the different types of lasers used and the radiation–matter interaction phenomena, particularly in terms of surface energy density and interaction times. Furthermore, the properties of the micro-structured surfaces are presented as a function of the parameters of the laser surface modification process and their evolution when they are subjected to contact with simulated physiological fluids.

The in vitro behavior of the laser-modified bioactive glass surface demonstrates that, by selecting the appropriate laser radiation and the appropriate process conditions, it is possible to produce a selective change in the osteoconductivity process.

Antibacterial coatings produced on the surface of biomaterials have received considerable attention due to the possibility of protecting medical implants placed in the human body against bacterial colonization resulting in inflammation of the surrounding tissues. According to various sources, the percentage of all infections can reach up to 30% of all implanted materials, leading to serious consequences including the necessity of surgical intervention. Thus, a number of methods allowing the production of antibacterial coatings has been developed. Micro-arc oxidation, considered as a simple and environmentally friendly method of functional coating deposition on top of so-called “valve metals”, is gaining in importance in this field. The relative simplicity in the mixing of electrolyte constituents makes the incorporation of antibacterial elements possible.

In the present work, the coatings were produced by the micro-arc oxidation method on the surface of commercially pure titanium subjected to plastic deformation by means of hydrostatic extrusion. Metallic (Ag) and ceramic (ZrO₂/ ZnO/CeO2) types of antibacterial agents were applied. The substrate material presents strong substrate anisotropy, which strongly affects the microstructure and the functional properties of the produced coatings. Therefore, the use of advanced methods of scanning and transmission electron microscopy and X-ray photoelectron spectroscopy allowed us to optimize the parameters of the micro-arc oxidation process and reveal the mechanisms of the incorporation of antibacterial additions into the titanium oxide coating.

Acknowledgements

This research was conducted within the framework of a project funded by the National Science Center of Poland, under grant number UMO-2020/39/D/ST8/01783.

Spin-assisted layer-by-layer (LbL) assembly is an innovative method for producing nanostructured thin films, offering enhanced efficiency and precision over traditional dip-coating techniques. This method enables significantly faster deposition and bilayer cycle times while optimizing material usage. In addition, spray LbL systems present advantages in speed and scalability for large-area substrates. By integrating these approaches, spin-spray-assisted LbL assembly allows for rapid assembly and extensive coverage of substrates. In this study, we demonstrated the efficacy of spin-spray LbL assembly in fabricating a thin-film composite nanofiltration (NF) membrane.

In this work, TFC NF consists of multiple layers of polyelectrolyte, and a metal–organic framework (MOF-303) was fabricated to enhance the membrane's biofouling resistance. Polyethyleneimine (PEI) and poly (sodium-4-styrene sulfonate) (PSS) were sprayed alternately and deposited on the top of a spinning polyethersulfone (PSF) ultrafiltration support to construct thin-film composite NF.

The resulting membrane was examined using standard nanofiltration membrane testing, and its performance is comparable to commercial NF. For instance, five bilayers of PEI/PSS NF membrane, i.e., (PEI/PSS)₅, showed a rejection rate of 42.65 ± 0.17 % and a permeability of 9.46 ± 0.14 l/h.bar.m^2, while a commercial NFX membrane from Synder Inc. showed a rejection rate of 53.66 ± 3.23 % and a permeability of 3.51 ± 0.42 l/h.bar.m². We fabricated a PEI/PSS membrane coated with MOF303 as the outermost layer. From our preliminary investigation, (PEI/PSS)5-MOF303 with an MOF concentration of 0.05 wt% exhibited a rejection rate of 18.94 ± 1.58% and a permeability of 0.91 ± 0.13 l/h.bar.m². Although this is still a preliminary result, this work shows that spin- and/or spin-spray-assisted layer-by-layer assembly is a promising method for fabricating membranes for various applications. Some further details, such as surface characteristics, are also provided in this work.

C/C composites exhibit a unique property profile, including high specific strength, flexural strength, excellent thermal shock resistance and low density. These properties make C/C an attractive material with great potential for high-temperature applications such as furnace technology. However, the low oxidation resistance of the material at high temperatures as well as its low wear resistance are critical factors that restrict its in-service lifetime and can lead to premature material failure.

This study investigates to what extent oxidation and wear resistance can be increased by the deposition of atmospheric plasma-sprayed coatings. Therefore, different coating systems are investigated, which consist of Mo or Si as intermediate coating and Al₂O₃, Al₂O₃-8%Cr₂O₃, Al₂O₃-40%TiO₂, an experimental (Al,Cr,Ti)₂O₃ solid solution or Yb₂Si₂O₇ as top coat. The wear resistance is determined by means of a ball-on-disc test, while the oxidation protection and damage mechanisms of the coating systems are evaluated by thermocyclic tests up to 1000 °C and rapid cooling in air. The microstructure of the coatings is analyzed using a scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD).

The results show that atmospheric plasma-sprayed coatings, despite their typical microstructure, which is characterized by pores and microcracks, can significantly improve the oxidation resistance of the C/C composite by reducing the rate of degradation in an oxidative environment. In addition, the oxide ceramic coatings provide considerably higher wear resistance than the C/C composite.

Various halide perovskite crystals based on CH₃NH₃PbI₃ (abbreviated MAPbI₃) are expected to become next-generation solar cell materials and are currently undergoing research and development worldwide. However, despite its high photoelectric conversion efficiency, MAPbI₃ has an unstable structure due to the presence of CH₃NH₃ (MA) organic molecules, and the decomposition of CH₃NH₃ from CH₃NH₃PbI₃ in the atmosphere results in the formation of PbI₂. The expensive 2,2',7,7'-tetrakis (N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (spiro-OMeTAD) is widely used throughout the world as a hole transport material in perovskite solar cells. To enhance hole transport, spiro-OMeTAD needs dopants such as lithium bis(trifluoromethane sulfonyl) imide and 4-tert-butylpyridine, which are highly hygroscopic and accelerate degradation of the perovskite layer when moisture is absorbed. Therefore, it is necessary to find alternative hole transport materials. In this study, decaphenylcyclopentasilane (DPPS) was selected as a material to modify the perovskite surface, and fabrication of perovskite photovoltaic devices in air and under unsealed conditions was attempted. DPPS is stable in air at temperatures up to 300°C and has the potential to suppress MA desorption; additionally,high-temperature heat treatment can form dense cubic perovskite, which is a stable phase at high temperatures. Polysilane has also been reported to function as a hole transport material, and is also expected to improve photoelectric conversion properties by using the DPPS as a hole transport layer. The fabrication of perovskite photovoltaic devices with DPPS by the air blow method in air could greatly simplify the manufacturing process without using a glove box and stabilize the solar cell characteristics.

In recent years, photovoltaics has attracted attention as a clean energy source. Although silicon-based materials are the mainstay of solar cells, organic–inorganic hybrid perovskite crystals are a candidate alternative. Perovskite solar cells can be lightweight and flexible devices manufactured by easy methods, and some have been developed to achieve photoelectric conversion efficiencies comparable to silicon-based materials. However, one of the organic cations present in perovskite crystals, methylammonium (MA), is prone to decomposition and desorption, leading to device instability. To address this issue, composition control using additives and optimizations of device structures through passivation techniques have been actively explored. In addition, encapsulation with films and improvements in film fabrication techniques have been pursued to achieve uniform thin-film formation. Various additives have been studied, including organic molecules such as guanidinium (GA) and ethylammonium, as well as alkali metal cations like cesium (Cs). Among these, dimethylammonium (DMA) has a larger molecular radius and possesses high molecular symmetry. The introduction of DMA into formamidinium (FA)-based perovskite crystals has been reported to limit the motion of FA, and to promote crystal growth in Cs-based perovskite crystals. In this study, the effects of DMA addition to MA-based perovskite crystals were investigated, and the photovoltaic properties of solar cells fabricated using these crystals were reported. Additionally, first-principles calculations were also carried out to evaluate performance in conjunction with experiments.

Introduction

Thin film deposition is an essential process in various industries, including optics, electronics, and aerospace. Among the most effective techniques, Physical Vapor Deposition (PVD) and Ion-Assisted Deposition (IAD) provide high-quality coatings with improved adhesion, mechanical strength, and optical performance. The choice of deposition materials is critical, as it directly influences the film's durability, functionality, and efficiency.

Methods

PVD involves transferring material from a source to a substrate in a vacuum environment. Common methods include evaporation and sputtering, where the material is either thermally vaporized or ejected by high-energy ion bombardment. IAD enhances PVD by introducing ion beams during deposition, improving film density, adhesion, and stress control. The selection of deposition materials depends on properties such as melting point, optical transparency, hardness, and chemical stability.

Results

Studies show that materials like titanium (Ti), silicon dioxide (SiO₂), and aluminum oxide (Al₂O₃) perform exceptionally well in PVD coatings, particularly for optical and wear-resistant applications. When combined with IAD, these films exhibit higher density, reduced defects, and better environmental resistance. However, materials with low thermal stability or high volatility require optimized deposition conditions to achieve uniform coatings.

Conclusions

The effectiveness of thin film deposition relies on selecting suitable materials and optimizing process parameters. PVD ensures high-quality coatings, while IAD further refines film characteristics, enhancing durability and performance. As deposition technologies evolve, new material innovations will continue to expand thin film applications across multiple industries, driving advancements in optics, electronics, and protective coatings. Understanding the interplay between deposition techniques and material properties is essential for producing high-performance thin films.

Perovskite solar cells (PSCs) have emerged as a groundbreaking photovoltaic technology, achieving power conversion efficiencies exceeding 25% with the integration of organic small-molecule hole transport materials (HTMs). Despite this significant advancement, large-scale commercialization remains hindered by the high cost of HTMs and the inherent instability of perovskite materials. Among the most widely used HTMs, Spiro-OMeTAD exhibits excellent optoelectronic properties; however, its complex synthesis and costly purification pose major barriers to widespread adoption. Overcoming these challenges requires the development of alternative, cost-effective HTMs with comparable or enhanced performance to improve both the efficiency and stability of PSCs.

This study explores the optoelectronic properties of carbazole-based derivatives as potential HTMs for PSC applications. Thin films were fabricated via the sol–gel spin coating technique on glass substrates, using chlorobenzene as the solvent. The molecular structure of the investigated compounds was confirmed through FTIR analysis, while UV-visible absorption and photoluminescence spectroscopy were employed to assess theiroptical properties. The resulting films exhibited high transparency in the visible spectrum and strong UV absorption, highlighting their suitability for photovoltaic integration. The estimated optical bandgap of the studied compounds was approximately 2.8 eV. Furthermore, a strong green emission in the visible region further underscores their potential for optoelectronic applications.

Kapton can be classified as an optical-grade plastic material because its amorphous nature does not allow light-scattering phenomena. Kapton films are amber-colored and have a unique optical absorption spectrum, characterized by a high transmittance value above 500nm (from yellow-red to near-infrared spectral regions) and an extremely high absorbance value below 500nm (from blue-violet to ultra-violet spectral regions). Owing to these special optical characteristics, Kapton films can be used as optical limiters (i.e., absorption-type optical filters), specifically as longwave pass (LWP) filters, and such optical devices can be used as ‘optical windows’ for many technological applications like the protection of sensors, optoelectronic devices (e.g., IR sensors and detectors), etc., from high-energy radiation (e.g., UV light, X-ray, etc.). This thermoplastic polymer has a very high thermal stability; indeed, its maximum service temperature is ca. 400°C. However, Kapton can be carbonized/graphitized by heating at very high temperatures (above 1000°C) to produce well-oriented graphite films. This process can be controlled and used to change Kapton's absorption profile. In particular, it is possible to modulate Kapton's optical absorption behavior by heating the polymer at temperatures slightly above 400°C. In particular, heating Kapton above 400°C leaves the film's optical transparency practically unmodified but causes a red-shift of the cut-on edge wavelength because of the formation of conjugated structures, with delocalized π-bonded electrons, in the Kapton chemical structure (very mild carbonization process). Therefore, it is possible to tune the cut-on edge wavelength of this LWP filter simply by applying a controlled thermal annealing treatment to the pristine film. Here, the optical properties of Kapton films modified by thermal treatment at temperatures higher than 400°C have been investigated by absorption optical spectroscopy (UV-Vis spectroscopy).

Introduction: Antibacterial coatings are becoming essential in construction materials to prevent microbial growth and improve hygiene, particularly in environments prone to bacterial contamination. Zinc oxide (ZnO) nanoparticles have emerged as a highly effective antimicrobial additive, offering unique properties such as high surface area, photocatalytic activity, and the ability to generate reactive oxygen species. When incorporated into cementitious coatings, ZnO nanoparticles provide dual benefits by enhancing both mechanical properties and antimicrobial functionality.

Methods: Recent advancements highlight the potential of ZnO-enhanced cement coatings to inhibit common pathogens, including Escherichia coli and Staphylococcus aureus. The antibacterial activity stems from the nanoparticles' ability to disrupt bacterial membranes and produce reactive oxygen species, effectively controlling microbial growth.

Results: The addition of ZnO improves the durability and compressive strength of cement, ensuring the material's structural integrity. The uniform dispersion of zinc oxide nanoparticles in the cement matrix contributes to consistent antibacterial performance and increased durability.

Conclusion: Recent studies have shown that ZnO-based antibacterial coatings represent a sustainable and innovative approach to addressing hygiene challenges in construction while maintaining high material performance. Future research is needed to optimize nanoparticle concentrations, ensure long-term antimicrobial efficacy, and evaluate the environmental and economic impacts of these coatings. This integration of functionality and durability underscores the transformative potential of ZnO nanoparticle-based coatings in modern construction and infrastructure.