Accurate characterization of single track-etched, conical nanopores

Single track-etched conical nanopores in polymer foils have attracted considerable attention in recent years due to their potential applications in biosensing, nanofluidics, information processing, and other fields. The performance of a nanopore critically depends on the size and shape of its narrowest, nanometer-sized region. In this paper, we reconstructed the profiles of both doubly-conical and conical pores, using an algorithm based on conductometric measurements performed in the course of etching, coupled with SEM data. We showed that pore constriction deviates from the conical shape, and the deviation depends on the energy loss of the particle that produced the track. Funnel-like profiles of tracks of four ions with different atomic numbers were derived from experimental data. The simulations, using a Poisson–Nernst–Planck model, demonstrated that the ion current rectification properties of the funnel-shaped asymmetrical pores significantly differ from those of conical ones if the tip radius of the pore is smaller than 10 nm. Upon subjecting to further etching, the pores gradually approach the ‘‘ideal’’ conical geometry, and the ion transport properties of these two pore configurations become almost indistinguishable.The authors are grateful to the Material Research group (GSI Darmstadt) for providing irradiated samples. The authors thank O. M. Ivanov for the irradiation of the polymer foils with accelerated ions. The help with SEM imaging provided by N. E. Lizunov is also appreciated. P. R. acknowledges financial support from the Generalitat Valenciana (project PROMETEO/GV/0069), Ministry of Science and Innovation of Spain, Materials Program (project MAT2012-32084), and FEDER. 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Study of deuterium plasma interaction with a tungsten target within RPI-IBIS facility

The paper presents results of experimental research on the interaction of a pulsed plasma-ion stream with a tungsten (W) target. The pulsed deuterium plasma was produced within the RPI-IBIS (Multi-Rod Plasma Injector) facility at IPJ in Swierk. Measurements were carried out by means of optical spectroscopy and corpuscular diagnostic techniques. Structural changes in the irradiated targets were investigated with a SEM. Before experiments with the W-target there were determined operational conditions, when clean deuterium plasma streams can be generated. For that purpose a so-called “slow or PID (Plasma Ion Deposition) mode” of the RPI-IBIS operation was chosen. Particular attention was paid to the identification of spectral lines from WI and WII species. The obtained results, i.e. optical spectra and other characteristics have demonstrated applicability of the RPI-IBIS facility for research on the interaction of plasma streams with W-targets, e.g. those constituting some internal parts of fusion facilities.Представлено результати експериментальних досліджень по взаємодії імпульсного плазмово-іонного потоку з вольфрамовою мішенню. Імпульсні дейтерієві потоки плазми генерувались в СПІ-ІБІС (стержневий плазмовий інжектор), який знаходиться в ІЯП у Шверку. Виміри проводились за допомогою оптичної спектроскопії та корпускулярної діагностики. Структурні зміни облучаємої мішені досліджувались за допомогою SEM. Перед експериментами з вольфрамовою мішенню визначались робочі умови, коли генерувались чисті дейтерієві плазмові потоки. Був вибраний так званий режим “повільний або PID-моди” (плазмового іонного осадження). Частична увага приділялась ідентифікації спектральних ліній WI та WII. Отримані результати, оптичні спектри та інші характеристики, продемонстрували можливість застосовувати установку СПІ-ІБІС для досліджень взаємодії плазмових потоків з W-мішенню, які складають деякі внутрішні частини термоядерного реактору.Представлены результаты экспериментальных исследований по взаимодействию импульсного плазменно-ионного потока с вольфрамовой мишенью. Импульсные дейтериевые потоки плазмы генерировались внутри СПИ-ИБИС (стержневой плазменный инжектор), который расположен в ИЯП в Шверке. Измерения проводились с помощью оптической спектроскопии и корпускулярной диагностики. Структурные изменения облучаемой мишени исследовались с помощью SEM. Перед экспериментами с вольфрамовой мишенью определялись рабочие условия, когда генерировались чистые дейтериевые плазменные потоки. Для этой цели был выбран так называемый режим “медленной или PID-моды” (плазменного ионного осаждения). Частичное внимание уделялось идентификации спектральных линий WI и WII. Полученные результаты, оптические спектры и другие характеристики, продемонстрировали применимость установки СПИ-ИБИС для исследований взаимодействия плазменных потоков с W-мишенью, которые составляют некоторые внутренние части термоядерного реактора

PET-MOF-CLEANWATER Joint Poland – South Africa Project

Celem projektu PET-MOF-CLEANWATER jest wytworzenie nowych zaawansowanych materiałów adsorpcyjnych na bazie porowatych metaloorganicznych polimerów koordynacyjnych (sorbenty typu MOF) z wykorzystaniem odpadów PET jako surowca do pozyskania liganda tereftalowego. Uzyskano pozytywne wyniki badań laboratoryjnych. Prowadzone są prace dla wykazania przydatności materiałów sorpcyjnych produkowanych z wykorzystaniem odpadowego PET do usuwania szkodliwych pierwiastków z roztworów wodnych.The aim of PET-MOF-CLEANWATER project is to produce new advance sorption materials on the base of porous metaloorganic coordinated polymers (sorbents MOF type) with using terephtalic linker recovered from waste PET. The positive results of laboratory investigations were obtained. Works for removal of the hazardous elelements removal from water solutions using sorption materials formed from waste PET are carried out

Multi-Elemental Coatings on Zirconium Alloy for Corrosion Resistance Improvement

Zirconium alloys are commonly used as a cladding material for fuel elements in nuclear reactors. This application is connected with zirconium alloy’s good resistance to water corrosion and radiation resistance under normal working conditions. In the case of severe accident conditions, the possibly very fast oxidation of zirconium alloys in steam or/and air atmosphere may result in the intense generation of hydrogen and explosion of the hydrogen oxide mixture. The development of a solution to minimize the aforementioned risk is of interest. One of the actual concepts is to improve the oxidation resistance of Zr alloy cladding with protective coatings. This study aimed to develop, form, and investigate new coatings for zirconium alloy Zry-2. Multi-elemental Physical Vapour Deposition (PVD) coatings with Cr, Si, and Zr were considered for Institute of Nuclear Chemistry and Technology) INCT as corrosion protective coatings for nuclear fuel claddings. Heat treatment at 850–1100 °C/argon, air oxidation processes at 700 °C/1–5 h, and a long-term corrosion test in standard conditions for Pressure Water Reactor (PWR) reactors (360 °C/195 bar/water simulating the water used in PWR) were carried out. Initial, modified, and oxidized materials were characterized with Scanning Electron Microscopy (SEM) (morphology observations), Energy Dispersive Spectroscopy (EDS) (elemental composition determination), and X-ray Diffraction (XRD) (phase composition analysis). Slower oxidation processes and a smaller oxidation rate, in the case of modified material investigations, were observed, as compared with the unmodified material. The obtained results displayed a protective character against the oxidation of formed layers in the defined range of parameters in the process

Nanopores with controlled profiles in track - etched membranes

Track-etched membranes are porous systems consisting of a polymer foil with thin channels-pores - from surface to surface. The increasing interest in this kind of material is connected with the development of nanoporous materials with unique properties such as diode-like effects in membranes with highly asymmetrical nanopores. The materials can be used for molecular sensors and atom beam optics, development of nanocapillary bodies for modelling the transport of molecules and ions in constrained volumes. Control over pore geometry opens the way to a number of new applications of track-etch membranes (TMs). The nanopores were obtained by the ion-track etching method using surfactant-doped alkaline solutions. Control over the pore profile and dimensions was achieved by varying the alkali concentration in the etchant and the etching time. The pore geometry was characterized in detail using field-emission scanning electron microscopy (SEM). SEM images of the surfaces and cleavages of TMs with different pore morphology are shown

Radiation synthesis of silver nano- and microparticles in cellulose fibers

Polymer nanocomposites containing metal nanoparticles have attracted a great interest due to their unique chemical and physical properties. “Green” chemistry promotes application of natural fibers in such structures, among them cellulose is one of the most frequently used. However, cellulose fabric have ability to absorb moisture, so under certain conditions of humidity and temperature they can be subjected to microbial attack. One of the most popular and best known antibacterial agents is silver, which serves as a potential antibacterial material acting against an exceptionally broad spectrum of bacteria including activity against antibiotic-resistant bacteria. Silver nanoparticles (Ag NPs) were grown at the cellulose fibers surface by direct reduction of AgNO3 with electron beam (EB) application. Nanocomposites obtained according to the method described in the text were investigated with X-ray diffraction (XRD), scanning electron microscope with back-scattered electrons detector (SEM-BSE) and energy dispersive spectroscopy (EDS) as well as thermogravimetric analysis (TGA) in order to determine influence of different size silver particles on fibers thermal properties