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Adaptability of Electrospun PVDF Nanofibers in Bone Tissue Engineering
(MDPI, 2025-01-25) Havlíková, Tereza; Papež, Nikola; Fohlerová, Zdenka; Kaspar, Pavel; Dallaev, Rashid; Částková, Klára; Ţălu, Ştefan
This study focused on the development of a suitable synthetic polymer scaffold for bone tissue engineering applications within the biomedical field. The investigation centered on electrospun polyvinylidene fluoride (PVDF) nanofibers, examining their intrinsic properties and biocompatibility with the human osteosarcoma cell line Saos-2. The influence of oxygen, argon, or combined plasma treatment on the scaffold’s characteristics was explored. A comprehensive design strategy is outlined for the fabrication of a suitable PVDF scaffold, encompassing the optimization of electrospinning parameters with rotating collector and plasma etching conditions to facilitate a subsequent osteoblast cell culture. The proposed methodology involves the fabrication of the PVDF tissue scaffold, followed by a rigorous series of fundamental analyses encompassing the structural integrity, chemical composition, wettability, crystalline phase content, and cell adhesion properties.
Piezophotocatalytic Activity of PVDF/Fe3O4 Nanofibers: Effect of Ultrasound Frequency and Light Source on the Decomposition of Methylene Blue
(ACS Publications, 2025-05-29) Rabadanova, Alina; Selimov, Daud; Gulakhmedov, Rashid; Magomedova, Asiyat; Ronoh, Kipkurui; Částková, Klára; Sobola, Dinara; Kaspar, Pavel; Shuaibov, Abdulatip; Abdurakhmanov, Magomed; Kh. Rabadanov, Murtazali; Ramazanov, Shikhgasan; Orudzhev, Farid
This study investigates the piezophotocatalytic (PPhC) performance of electrospun nanofibrous membranes composed of polyvinylidene fluoride (PVDF) and magnetite (Fe3O4) nanoparticles. The composite membranes were synthesized via electrospinning, with optimized parameters to promote -phase crystallinity and uniform fiber morphology. Structural and phase analyses by SEM, FTIR, Raman, and XPS confirmed the predominance of the electroactive -phase (99.8%) in the composite, as well as strong interfacial interaction between Fe3O4 and the PVDF matrix. The composites exhibited significantly enhanced surface hydrophilicity and piezoelectric response compared to pristine PVDF. The piezoelectric potential generation was confirmed using a flexible piezoelectric nanogenerator (PENG), where a 3 × 1 cm membrane generated output voltages up to 2 V under periodic mechanical deformation at 4 Hz. Photocatalytic and piezophotocatalytic degradation of methylene blue (MB) was carried out under UV and visible light at varying ultrasonic frequencies. Maximum PPhC efficiency was achieved at 40 kHz, with 93% dye degradation in 60 min and a reaction rate constant exceeding the sum of photocatalysis and piezocatalysis by 13%, indicating a pronounced synergistic effect. Reactive oxygen species trapping and fluorescence spectroscopy confirmed •OH as the dominant oxidant. H2O2 productivity under PPhC reached 1700 mol·g–1·h–1 in pure water, with a light-to-chemical energy conversion efficiency of 0.26%. Additionally, experiments conducted under an alternating magnetic field (0.3 T, 1.3 Hz) demonstrated 50% MB degradation within 240 min, revealing the contribution of magnetoelectric coupling as an alternative catalytic activation mechanism. The results suggest that PVDF/Fe3O4 nanocomposites are highly promising for multifunctional catalytic applications, combining piezoelectric, photo-, and magnetoelectric activation for efficient water purification and green oxidant production.
Correlation of Dielectric Properties and Vibrational Spectra of Composite PVDF/Salt Fibers
(MDPI, 2024-08-26) Dallaev, Rashid; Sarkar, Ranjini; Selimov, Daud; Papež, Nikola; Kočková, Pavla; Schubert, Richard; Částková, Klára; Orudzhev, Farid; Ramazanov, Shihgasan; Holcman, Vladimír
Nitride salts were added to polyvinylidene fluoride fibers and then the fiber mats were prepared by electrospinning. An experimental investigation of the structure was provided by Raman, FTIR, SEM, and XRD. The phase ratio of the polymer was studied both theoretically and experimentally in connection with the addition of the hydrates Mg(NO3)2, Ca(NO3)2, and Zn(NO3)2 salts. The com-parison of simulated and experimental data for vibrational spectroscopies is discussed. We provide a comparison of triboelectric, dielectric, and compositional characterization of PVDF fibers doped with three types of nitride hydrates. Doping of PVDF fibers with magnesium nitrate hexahydrate leads to significant improvement of the triboelectric performance.
Exploring Hydrogen Embrittlement: Mechanisms, Consequences, and Advances in Metal Science
(MDPI, 2024-06-17) Sobola, Dinara; Dallaev, Rashid
Hydrogen embrittlement (HE) remains a pressing issue in materials science and engineering, given its significant impact on the structural integrity of metals and alloys. This exhaustive review aims to thoroughly examine HE, covering a range of aspects that collectively enhance our understanding of this intricate phenomenon. It proceeds to investigate the varied effects of hydrogen on metals, illustrating its ability to profoundly alter mechanical properties, thereby increasing vulnerability to fractures and failures. A crucial section of the review delves into how different metals and their alloys exhibit unique responses to hydrogen exposure, shedding light on their distinct behaviors. This knowledge is essential for customizing materials to specific applications and ensuring structural dependability. Additionally, the paper explores a diverse array of models and classifications of HE, offering a structured framework for comprehending its complexities. These models play a crucial role in forecasting, preventing, and mitigating HE across various domains, ranging from industrial settings to critical infrastructure.
FUNCTIONAL TUNGSTEN-BASED THIN FILMS AND THEIR CHARACTERIZATION
(TANGER Ltd, 2024-01-08) Košelová, Zuzana; Horáková, Lenka; Sobola, Dinara; Burda, Daniel; Knápek, Alexandr; Fohlerová, Zdenka
Anodization is a technique that can be used to create thin layers of oxide on the surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten is still often choice for cold field emitters in commercial microscopy applications. His suitable quality can be improved even more by deposition of thin layer. Not only emission characteristic can be improved, but also emitter operating time can be prolonged. Tungsten oxide is known for its excellent resistance to corrosion and chemical attack, which is due to its stable crystal structure and the strong chemical bonds between tungsten and oxygen atoms. Many techniques were applied for this purpose, with various advantages and disadvantages. For this work anodization was chosen because of controllable uniform material coverage and easy accessibility without the need for expensive complex equipment. The anodization process involves applying an electrical potential to tungsten while it is immersed in an electrolyte solution. This causes a thin layer of tungsten oxide to form on the surface of the metal. The thickness and properties of the resulting oxide layer can be controlled by adjusting the anodization conditions, such as the electrolyte solution, voltage, and the duration of the process. In this work, H3PO4 was used as electrolyte To test whether these tungsten oxide layers would be viable for electron emitters, for use in electron guns and other devices that require high-quality electron emitters, we put them through a series of tests. Properties were evaluated using appropriate techniques. In general, anodization of tungsten to create thin tungsten oxide layers is a promising technique for producing high-quality electron emitters.

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