Uroš Cvelbar

Bio: Uroš Cvelbar is an academic researcher from Jožef Stefan Institute. The author has contributed to research in topics: Materials science & Surface modification. The author has an hindex of 38, co-authored 175 publications receiving 5117 citations. Previous affiliations of Uroš Cvelbar include Center for Functional Nanomaterials & University of Sydney.

Surface modification of polyester by oxygen- and nitrogen-plasma treatment

Abstract: In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by plasma treatment. The samples were treated by nitrogen and oxygen plasma for different time periods between 3 and 90 s. The plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 1015 m−3, and the neutral atom density was about 4 × 1021 m−3 for oxygen and 1 × 1021 m−3 for nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen-plasma-treated samples showed much more pronounced changes in the surface topography compared to those treated by nitrogen plasma. The contact angle of a water drop decreased from 75° for the untreated sample to 20° for oxygen and 25° for nitrogen-plasma-treated samples for 3 s. It kept decreasing with treatment time for both plasmas and reached about 10° for nitrogen plasma after 1 min of plasma treatment. For oxygen plasma, however, the contact angle kept decreasing even after a minute of plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or nitrogen plasma, respectively. Ageing effects of the plasma-treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later. Copyright © 2008 John Wiley & Sons, Ltd.

Spontaneous Growth of Superstructure α-Fe2O3 Nanowire and Nanobelt Arrays in Reactive Oxygen Plasma

Abstract: One-dimensional a-Fe2O3 is a promising nanomaterial for advanced applications in catalysis and water splitting, environmental protection, sensors, dye solar cells, magnetic storage media, bioprocessing, and controlled drug delivery and detection, especially as carriers of antigens for prion detection and PCR manipulation. a-Fe2O3 nanowires have been successfully synthesized by various methods based on templates, hydrothermal conditions, sol–gel-mediated reactions, solvothermal conditions, gas decomposition, direct thermal oxidation (in a gas atmosphere of CO2, SO2, O2, and NO2), [7] chemical vapor deposition (CVD), and plasmaenhanced chemical vapor deposition (PECVD). The methods based on direct thermal oxidation, gas decomposition, and CVD reported to date require long synthesis times and high temperatures and therefore limit the efficiency of oxide nanowire synthesis. The application and commercialization of nanowires or nanobelts requires simple synthetic methods that can be scaled for both large areas and large quantities. Recently, we discovered a new universal method for the synthesis of transition metal oxide nanowires and nanobelts by direct plasma oxidation of bulk materials. It has been successfully applied for the rapid synthesis of high-density niobium oxide nanowires. In this process, there is no

Plasma nanoscience : setting directions, tackling grand challenges

Abstract: This review paper presents historical perspectives, recent advances and future directions in the multidisciplinary research field of plasma nanoscience The current status and future challenges are presented using a three-dimensional framework The first and the largest dimension covers the most important classes of nanoscale objects (nanostructures, nanofeatures and nanoassemblies/nanoarchitectures) and materials systems, namely carbon nanotubes, nanofibres, graphene, graphene nanoribbons, graphene nanoflakes, nanodiamond and related carbon-based nanostructures; metal, silicon and other inorganic nanoparticles and nanostructures; soft organic nanomaterials; nano-biomaterials; biological objects and nanoscale plasma etching In the second dimension, we discuss the most common types of plasmas and plasma reactors used in nanoscale plasma synthesis and processing These include low-temperature non-equilibrium plasmas at low and high pressures, thermal plasmas, high-pressure microplasmas, plasmas in liquids and plasma–liquid interactions, high-energy-density plasmas, and ionized physical vapour deposition as well as some other plasma-enhanced nanofabrication techniques In the third dimension, we outline some of the 'Grand Science Challenges' and 'Grand Socio-economic Challenges' to which significant contributions from plasma nanoscience-related research can be expected in the near future The urgent need for a stronger focus on practical, outcome-oriented research to tackle the grand challenges is emphasized and concisely formulated as from controlled complexity to practical simplicity in solving grand challenges

Copper oxide nanowires: a review of growth.

Abstract: Cuprous oxide (Cu(2)O) and cupric oxide (CuO) nanowires have started playing important roles in energy conversion devices and optoelectronic devices. Although the desired advanced properties have been demonstrated, these materials cannot yet be produced in large-bulk quantities in order to bridge the technological transfer gap for wider use. In this respect, the quest for the most efficient synthesis process which yields not only large quantities but also high quality and advanced material properties continues. This paper gives an extensive review of copper oxide nanowire (NW) synthesis by all methods and routes by which various researchers have obtained their nanomaterial. These methods are critically overviewed, evaluated and compared. Methods of copper oxide NW growth include wet-chemical methods based on pure solution growth, electrochemical and hydrothermal routes as well as thermal and plasma oxidation methods. In terms of advanced nanowire synthesis, the fast thermal method or direct plasma oxidation as well as the combined hybrid wet-chemical method in which copper hydroxide NWs are produced and sequentially transformed by plasma oxidation which produces Cu(2)O NWs are seen as the most promising methods to explore in the near future. These methods not only yield large quantities of NWs, but produce high quality material with advanced properties.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Inorganic nanostructures for photoelectrochemical and photocatalytic water splitting

Abstract: The increasing human need for clean and renewable energy has stimulated research in artificial photosynthesis, and in particular water photoelectrolysis as a pathway to hydrogen fuel. Nanostructured devices are widely regarded as an opportunity to improve efficiency and lower costs, but as a detailed analysis shows, they also have considerably disadvantages. This article reviews the current state of research on nanoscale-enhanced photoelectrodes and photocatalysts for the water splitting reaction. The focus is on transition metal oxides with special emphasis of Fe2O3, but nitrides and chalcogenides, and main group element compounds, including carbon nitride and silicon, are also covered. The effects of nanostructuring on carrier generation and collection, multiple exciton generation, and quantum confinement are also discussed, as well as implications of particle size on surface recombination, on the size of space charge layers and on the possibility of controlling nanostructure energetics via potential determining ions. After a summary of electrocatalytic and plasmonic nanostructures, the review concludes with an outlook on the challenges in solar fuel generation with nanoscale inorganic materials.

One-Dimensional Metal-Oxide Nanostructures: Recent Developments in Synthesis, Characterization, and Applications

Abstract: 1D metal-oxide nanostructures have attracted much attention because metal oxides are the most fascinating functional materials. The 1D morphologies can easily enhance the unique properties of the metal-oxide nanostructures, which make them suitable for a wide variety of applications, including gas sensors, electrochromic devices, light-emitting diodes, field emitters, supercapacitors, nanoelectronics, and nanogenerators. Therefore, much effort has been made to synthesize and characterize 1D metal-oxide nanostructures in the forms of nanorods, nanowires, nanotubes, nanobelts, etc. Various physical and chemical deposition techniques and growth mechanisms are exploited and developed to control the morphology, identical shape, uniform size, perfect crystalline structure, defects, and homogenous stoichiometry of the 1D metal-oxide nanostructures. Here a comprehensive review of recent developments in novel synthesis, exceptional characteristics, and prominent applications of one-dimensional nanostructures of tungsten oxides, molybdenum oxides, tantalum oxides, vanadium oxides, niobium oxides, titanium oxides, nickel oxides, zinc oxides, bismuth oxides, and tin oxides is provided.