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Access status: Open Access ,
Bactericidal Properties of the Sol-gel Layer on Polymer Substrates in Medical Applications
(AGH University Press, 2024) Armatys, Paulina; Długoń, Elżbieta; Smółka, Wojciech; Sobota, Robert; Frączek-Szczypta, Aneta; Markowski, Jarosław; Stodolak-Zych, Ewa
Polymeric biomaterials are a group of plastics used in medical devices, implants, and artificial organ components. In order to maintain the higher asepticity of the products, solutions based on the modification of the volume or surface of a plastic with biocidal agents, e.g. antibiotics, nanoparticles, are used. One of the methods used to impart biocidal properties to the material can be the use of layers applied by the sol-gel method. The aim of this study was to produce homogeneous and durable coatings on inert and hydrophobic silicone surfaces based on polysiloxane sols with biocidal activity against model bacteria: Gram negative (Escherichia coli, Klebsiella pneumoniae) and Gram positive (Staphylococcus aureus, Enterococcus faecalis). This paper presents results of investigations on a commercial biomedical silicone material (DEMED Sp. zoo) modified with eight sols, siloxane (TD), phenol-siloxane (FD), siloxanealuminum (TD-Al), siloxane-titanium (TD-Ti), titanium (Ti), zinc (Zn), and TD and TD-Al sols modified with green tea extract (TD-GT, TD-Al-GT). The reference for the tested materials was unmodified silicone. In order to be prepared for coating, the siloxane samples were etched with hydrofluoric acid. Residual acid was removed from the silicone by washing and the substrates were then coated with sols by means of dip coating. The modified materials were then polymerized at 100°C for one week. The produced layered composites were subjected to microstructural, physicochemical, structural and microbiological analysis by contacting them with Gramm negative and Gramm positive bacteria. It was shown that the strongest biocidal properties were exhibited by samples modified with the sols based on - Zn, TD-Ti, Ti, TD-Al-GT and TD-GT.
Access status: Open Access ,
Comparative Analysis of Electrophoretic Deposition and Dip Coating for Enhancing Electrical Properties of Electrospun PVDF Mats Through Carbon Nanotube Deposition
(2025) Kopacz, Michał; Szewczyk, Piotr K.; Długoń, Elżbieta; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Integrating carbon nanotubes (CNTs) into electrospun polyvinylidene fluoride (PVDF) fibers is a promising approach for developing conductive and multifunctional materials. This study systematically compared two CNT deposition techniques, electrophoretic deposition (EPD) and dip coating (DC), in terms of their effectiveness in modifying the surface of aligned electrospun PVDF mats. Morphological characterization revealed that EPD produced more homogeneous and compact CNT coatings. In contrast, DC resulted in discontinuous and irregular layers regardless of deposition time. A key distinction between the two methods was the tunability of the coating: EPD allowed for precise control over CNT layer thickness and mass accumulation by adjusting the deposition time. In contrast, DC showed no significant changes in thickness with longer immersion. These structural differences translated into distinct electrical behaviors. Resistance measurements showed that EPD samples exhibited a substantial decrease in resistance with increasing deposition time, from 5.9 ± 2.5 kΩ to 0.2 ± 0.1 kΩ, indicating the formation of well-connected conductive pathways. On the other hand, DC samples maintained relatively constant, higher resistance values across all conditions. Additionally, EPD-coated mats demonstrated enhanced touch sensitivity, generating higher and more stable current responses compared to DC-deposited samples. These results confirm that EPD is a more effective, tunable method for fabricating conductive CNT coatings on electrospun PVDF mats, particularly for applications in flexible electronics and wearable sensors.
Access status: Open Access ,
Multifunctional, Flexible and Interactive PVDF Fibers with Tunable Conductivity via CNT Coatings for Sensing and Smart Textile Applications
(2025) Kopacz, Michał; Szewczyk, Piotr K.; Długoń, Elżbieta; Berniak, Krzysztof; Nizioł, Jacek; Jeleń, Piotr; Sitarz, Maciej; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Integrating electronics into textiles has the potential to revolutionize wearable devices, but achieving conductivity without compromising breathability and flexibility remains a challenge. Electrospun polyvinylidene fluoride (PVDF) fibers offer a porous and flexible scaffold but are inherently insulating. Previous methods for adding conductivity often reduce vapor permeability and mechanical performance. Here, this study reports a two-step fabrication strategy using electrophoretic deposition (EPD) of carbon nanotubes (CNTs) onto electrospun PVDF fibers, resulting in highly conductive (80 $\pm$ 6 $\Omega$), porous, and stretchable mats (elongation of ≈600%). The EPD process enables tunable conductivity while preserving fiber structure and water vapor transmission. The mats achieve significantly lower impedance and enhanced mechanical performance compared to existing coatings. This study demonstrates the use of these composites as sensors capable of detecting pressure, motion, respiration, and temperature. This multifunctionality, combined with scalable fabrication, highlights their potential in smart textiles. These findings open new opportunities for designing wearable sensors that unite functionality, user comfort, and durability.

Długoń, Elżbieta

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