Publications by authors named "Petr Sajdl"

5 Publications

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Antibacterial Properties of Plasma-Activated Perfluorinated Substrates with Silver Nanoclusters Deposition.

Nanomaterials (Basel) 2021 Jan 13;11(1). Epub 2021 Jan 13.

Department of Solid State Engineering, University of Chemistry and Technology Prague, 166 28 Prague, Czech Republic.

This article is focused on the evaluation of surface properties of polytetrafluoroethylene (PTFE) nanotextile and a tetrafluoroethylene-perfluoro(alkoxy vinyl ether) (PFA) film and their surface activation with argon plasma treatment followed with silver nanoclusters deposition. Samples were subjected to plasma modification for a different time exposure, silver deposition for different time periods, or their combination. As an alternative approach, the foils were coated with poly-L-lactic acid (PLLA) and silver. The following methods were used to study the surface properties of the polymers: goniometry, atomic force microscopy, and X-ray photoelectron microscopy. By combining the aforementioned methods for material surface modification, substrates with antibacterial properties eliminating the growth of Gram-positive and Gram-negative bacteria were prepared. Studies of antimicrobial activity showed that PTFE plasma-modified samples coated with PLLA and deposited with a thin layer of Ag had a strong antimicrobial effect, which was also observed for the PFA material against the bacterial strain of . Significant antibacterial effect against , and has been demonstrated on PTFE nanotextile plasma-treated for 240 s, coated with PLLA, and subsequently sputtered with thin Ag layer.
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http://dx.doi.org/10.3390/nano11010182DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828452PMC
January 2021

Plasmon-Induced Water Splitting-through Flexible Hybrid 2D Architecture up to Hydrogen from Seawater under NIR Light.

ACS Appl Mater Interfaces 2020 Jun 12;12(25):28110-28119. Epub 2020 Jun 12.

Department of Solid State Engineering, University of Chemistry and Technology, 16628 Prague, Czech Republic.

The efficient utilization of solar energy is the actual task of the present and near future. Thus, the preparation of appropriate materials that are able to harvest and utilize the broad wavelength range of solar light (especially commonly ignored near-infrared light region-NIR) is the high-priority challenging mission. Our study provides a rationally designed two-dimensional (2D) flexible heterostructures with photocatalytic activity for the production of "clean" hydrogen under NIR illumination, with the hydrogen production rate exceeding most 2D materials and the ability to use the seawater as a starting material. The proposed design utilizes the hybrid bimetallic (Au/Pt) periodic structure, which is further covalently grafted with a metal-organic framework MIL-101(Cr). The periodic gold structure is able to efficiently support the plasmon-polariton wave and to excite the hot electrons, which is further injected in the Pt and MIL-101(Cr) layers. The Pt and MIL-101(Cr) structures provide catalytic sites, which are saturated with hot electrons and efficiently initiate water splitting and hydrogen production. The MIL-101(Cr) layer also serves for repelling generated hydrogen bubbles. The mechanistic studies reveal the catalytic role of every element of the 2D flexible heterostructures. The maximum hydrogen output was achieved under plasmon resonance excitation in the NIR range, and it could be actively controlled by the applied LED wavelength.
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http://dx.doi.org/10.1021/acsami.0c04029DOI Listing
June 2020

The Photodynamic Properties and the Genotoxicity of Heat-Treated Silicalite-1 Films.

Materials (Basel) 2019 Feb 14;12(4). Epub 2019 Feb 14.

Power Engineering Department, University of Chemistry and Technology, Technická 3, 166 28 Prague 6, Czech Republic.

We investigated the use of a supported silicalite-1 film () as a promising coating for metallic materials used in the fabrication of prostheses. The role of carbonaceous residua present on high-temperature calcined- in generating singlet oxygen for future use as a sterilization method has also been addressed, and the potential genotoxicity of these residua in osteoblast-like cells has been investigated. Calcination of as-synthesized induced the appearance of a rather complicated mixture of aliphatic and aromatic species on its outer surface. A series of variously volatile polycyclic aromatic hydrocarbons (PAH), including naphthalene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene, were identified in micromole concentrations. Irradiation of these PAHs on calcined- immersed in air-saturated chloroform led to the formation of very low concentrations of singlet oxygen. However, an increased level of DNA damage was observed on calcined-SF by immunofluorescence staining of phosphorylated histone H2AX analyzed by flow cytometry.
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http://dx.doi.org/10.3390/ma12040567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416588PMC
February 2019

Nanocrystalline diamond protects Zr cladding surface against oxygen and hydrogen uptake: Nuclear fuel durability enhancement.

Sci Rep 2017 07 25;7(1):6469. Epub 2017 Jul 25.

Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 21, Prague 8, Czech Republic.

In this work, we demonstrate and describe an effective method of protecting zirconium fuel cladding against oxygen and hydrogen uptake at both accident and working temperatures in water-cooled nuclear reactor environments. Zr alloy samples were coated with nanocrystalline diamond (NCD) layers of different thicknesses, grown in a microwave plasma chemical vapor deposition apparatus. In addition to showing that such an NCD layer prevents the Zr alloy from directly interacting with water, we show that carbon released from the NCD film enters the underlying Zr material and changes its properties, such that uptake of oxygen and hydrogen is significantly decreased. After 100-170 days of exposure to hot water at 360 °C, the oxidation of the NCD-coated Zr plates was typically decreased by 40%. Protective NCD layers may prolong the lifetime of nuclear cladding and consequently enhance nuclear fuel burnup. NCD may also serve as a passive element for nuclear safety. NCD-coated ZIRLO claddings have been selected as a candidate for Accident Tolerant Fuel in commercially operated reactors in 2020.
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http://dx.doi.org/10.1038/s41598-017-06923-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526891PMC
July 2017

Mechanisms and efficiency of the simultaneous removal of metals and cyanides by using ferrate(VI): crucial roles of nanocrystalline iron(III) oxyhydroxides and metal carbonates.

Chemistry 2011 Aug 26;17(36):10097-105. Epub 2011 Jul 26.

Regional Centre of Advanced Technologies and Materials, Palacký University in Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic.

The reaction of potassium ferrate(VI), K(2)FeO(4), with weak-acid dissociable cyanides--namely, K(2)[Zn(CN)(4)], K(2)[Cd(CN)(4)], K(2)[Ni(CN)(4)], and K(3)[Cu(CN)(4)]--results in the formation of iron(III) oxyhydroxide nanoparticles that differ in size, crystal structure, and surface area. During cyanide oxidation and the simultaneous reduction of iron(VI), zinc(II), copper(II), and cadmium(II), metallic ions are almost completely removed from solution due to their coprecipitation with the iron(III) oxyhydroxides including 2-line ferrihydrite, 7-line ferrihydrite, and/or goethite. Based on the results of XRD, Mössbauer and IR spectroscopies, as well as TEM, X-ray photoelectron emission spectroscopy, and Brunauer-Emmett-Teller measurements, we suggest three scavenging mechanisms for the removal of metals including their incorporation into the ferrihydrite crystal structure, the formation of a separate phase, and their adsorption onto the precipitate surface. Zn and Cu are preferentially and almost completely incorporated into the crystal structure of the iron(III) oxyhydroxides; the formation of the Cd-bearing, X-ray amorphous phase, together with Cd carbonate is the principal mechanism of Cd removal. Interestingly, Ni remains predominantly in solution due to the key role of nickel(II) carbonate, which exhibits a solubility product constant several orders of magnitude higher than the carbonates of the other metals. Traces of Ni, identified in the iron(III) precipitate, are exclusively adsorbed onto the large surface area of nanoparticles. We discuss the relationship between the crystal structure of iron(III) oxyhydroxides and the mechanism of metal removal, as well as the linear relationship observed between the rate constant and the surface area of precipitates.
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http://dx.doi.org/10.1002/chem.201100711DOI Listing
August 2011