Copper has a strong bactericidal effect against multi-drug resistant pathogens and polyethers are known for their resistance to biofilm formation. Herein, we combined Cu nanoparticles (NPs) and a polyether plasma polymer in the form of nanocomposite thin films and studied whether both effects can be coupled. Cu NPs were produced by magnetron sputtering via the aggregation in a cool buffer gas whereas polyether layers were synthesized by Plasma-Assisted Vapor Phase Deposition with poly(ethylene oxide) (PEO) used as a precursor. In situ specific heat spectroscopy and XPS analysis revealed the formation of a modified polymer layer around the NPs which propagates on the scale of a few nanometers from the Cu NP/polymer interface and then transforms into a bulk polymer phase. The chemical composition of the modified layer is found to be ether-deficient due to the catalytic influence of copper whereas the bulk polymer phase exhibits the chemical composition close to the original PEO. Two cooperative glass transition phenomena are revealed that belong to the modified polymer layer and the bulk phase. The former is characterized by constrained mobility of polymer segments which manifests itself via a 30 K increase of dynamic glass transition temperature. Furthermore, the modified layer is characterized by the heterogeneous structure which results in higher fragility of this layer as compared to the bulk phase. The Cu NPs/polyether thin films exhibit reduced protein adsorption; however, the constrained segmental dynamics leads to the deterioration of the non-fouling properties for ultra-thin polyether coatings. The films are found to have a bactericidal effect against multi-drug resistant Gram-positive Methicillin-Resistant Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa.

The surface modification of TiO ₂ aerogel powders by cerium ions has led to enhanced photoinduced properties.

AC discharge in a dense hydrodynamic cavitation cloud in water, called CaviPlasma, has been studied at different discharge parameters. CaviPlasma stands for cavitation and plasma, which are two coupled basic phenomena of the novel technology enabling very high throughput of plasma water processing compared to other current technologies. In this article, the diagnostics and the properties of CaviPlasma discharge are discussed based on optical and electric characterization of the discharge phenomena together with the physico-chemical characterization of the plasma-treated water. The so-called unbridged mode of CaviPlasma operation is described, where the discharge propagates from a metal electrode towards a liquid electrode at the collapsing end of the cavitation cloud. The production of H, O and OH species in the discharge was proven by optical emission spectroscopy. The formation of hydrogen peroxide (H₂O₂) in water was determined by chemical methods. The energy yield for H₂O₂ generation is as high as 9.6 g kWh⁻¹ and the generation rate is up to 2.4 g h⁻¹. The degradation of phenol admixture in water was also studied. The article covers a parametric study enabling the development of tailored applications.

Plasma-activated water (PAW) is increasingly recognized for its bactericidal properties. To advance this technology toward practical applications and deepen the understanding of its mechanisms, it is crucial to study the storage stability of PAW, focusing on both its chemical composition and antimicrobial properties over time. In this study, PAW was produced using a surface dielectric barrier discharge applied to ultra-pure water. Six PAW samples were analyzed, with plasma exposure times of 10, 20, or 30 min, and with or without water recirculation. Chemical properties such as pH, electrical conductivity, and oxidation-reduction potential were monitored over 72 h of storage at 25 ^∘C. The kinetics of long-lived reactive oxygen and nitrogen species were also studied, with H 2 O 2 measured by visible spectrophotometry and NO 2 − and NO 3 − analyzed via ion chromatography. While H 2 O 2 and NO 2 − concentrations decreased during the storage, NO 3 − levels increased in all samples, reaching similar final concentrations independently on the water recirculation during plasma exposure. After 72 h, the bactericidal effect of PAW on Escherichia coli was evaluated for 10 and 30 min treatment times and compared to fresh samples. Although water recirculation initially provided stronger antimicrobial effects, after storage, both recirculated and non-recirculated PAW samples exhibited similar antimicrobial activity. This study demonstrates that PAW samples, regardless of the initial chemical composition, associated to water recirculation, achieve comparable antimicrobial properties after 72 h of storage, providing valuable insights for practical PAW applications.