Recent Advances in the Methods for Designing Superhydrophobic Surfaces

The investigations of superhydrophobicity and self-cleaning surfaces have been given a lot of attention in the last few decades. The surfaces having water contact angle larger than 90° are termed as hydrophobic surfaces and those which exhibit contact angle higher than 150° are said to be superhydrophobic. Such surfaces were first observed in nature in various plants and animals, for example, lotus leaf-like structures. Water repellence of various materials have shown great influences on various applications such as self-cleaning, anti-ageing, water-oil separation, water corrosion in electrical industry, water proof textiles, controlled transportation of fluids, etc. Generally, surface micro/nanostructuring combined with low surface energy of materials leads to extreme anti-wetting properties. The hundreds of research articles and more than 450 patents on the subject of nature mimicking self-cleaning surfaces prove the potential of this topic

White paper on the future of plasma science and technology in plastics and textiles

International audienceThis white paper considers the future of plasma science and technology related to the manufacturing and modifications of plastics and textiles, summarizing existing efforts and the current state-of-art for major topics related to plasma processing techniques. It draws on the frontier of plasma technologies in order to see beyond and identify the grand challenges which we face in the following 5–10 years. To progress and move the frontier forward, the paper highlights the major enabling technologies and topics related to the design of surfaces, coatings and materials with nonequilibrium plasmas. The aim is to progress the field of plastics and textile production using advanced plasma processing as the key enabling technology which is environmentally friendly, cost-efficient, and offers high-speed processing

Selective Plasma Etching of Polymeric Substrates for Advanced Applications

In today’s nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a “zoo” of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance

A review of plasma-assisted catalytic conversion of gaseous carbon dioxide and methane into value-added platform chemicals and fuels

CO(2) and CH(4) contribute to greenhouse gas emissions, while the production of industrial base chemicals from natural gas resources is emerging as well. Such conversion processes, however, are energy-intensive and introducing a renewable and sustainable electric activation seems optimal, at least for intermediate-scale modular operation. The review thus analyses such valorisation by plasma reactor technologies and heterogeneous catalysis application, largely into higher hydrocarbon molecules, that is ethane, ethylene, acetylene, propane, etc., and organic oxygenated compounds, i.e. methanol, formaldehyde, formic acid and dimethyl ether. Focus is given to reaction pathway mechanisms, related to the partial oxidation steps of CH(4) with O(2), H(2)O and CO(2), CO(2) reduction with H(2), CH(4) or other paraffin species, and to a lesser extent, to mixtures' dry reforming to syngas. Dielectric barrier discharge, corona, spark and gliding arc sources are considered, combined with (noble) metal materials. Carbon (C), silica (SiO(2)) and alumina (Al(2)O(3)) as well as various catalytic supports are examined as precious critical raw materials (e.g. platinum, palladium and rhodium) or transition metal (e.g. manganese, iron, cobalt, nickel and copper) substrates. These are applied for turnover, such as that pertinent to reformer, (reverse) water–gas shift (WGS or RWGS) and CH(3)OH synthesis. Time-on-stream catalyst deactivation or reactivation is also overviewed from the viewpoint of individual transient moieties and their adsorption or desorption characteristics, as well as reactivity

Ammonia plasma-treated carbon nanotube/epoxy composites and their use in sensing applications

Epoxy composites filled by multiwalled carbon nanotubes treated by inductively coupled ammonia plasma were prepared to improve composite intrinsic properties. The ammonia plasma treatment generated amine and oxygenated groups on the carbon nanotube surface, which facilitated its interaction with the epoxy ring and restricted the slippage of epoxy from the carbon nanotube surface. As a result, an improvement in the elastic modulus of the composite by the embedded carbon nanotubes and a decrease in the glass transition temperature and the cure degree were found. It indicated a strengthening effect of the carbon nanotube filler in the epoxy matrix explained by the generation of chemical reaction pathways between treated filler and the epoxy matrix detected by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy during different stages of the composite formation. To demonstrate the use of carbon nanotube-filled epoxy composites, a microstrip resonant vapor sensor was assembled that was used to detect the occurrence of volatile organic compounds and to monitor the ambient temperature below and over the glass transition temperature. © BME-PT.RP/CPS/ 2020/006; 67985874, CZ.1.05/2.1.00/19.0409; Akademie Věd České Republiky, AV ČR; Javna Agencija za Raziskovalno Dejavnost RS, ARRS: L2-6769, P2-0082Ministry of Education, Youth and Sports of the Czech Republic-DKRVO [RP/CPS/2020/006]; National Budget of the Czech Republic: the project CPSV-Strengthening Research Capacity [CZ.1.05/2.1.00/19.0409]; Czech Academy of Sciences, Czech Republic [RVO: 67985874]; Slovenian Research Agency (ARRS)Slovenian Research Agency - Slovenia [L2-6769, P2-0082

Plasma-enabled sensing of urea and related amides on polyaniline

The atmospheric pressure plasma jet (APPJ) was used to enhance the sensitivity of industrially important polyaniline (PANI) for detection of organic vapors from amides. The gas sensing mechanism of PANI is operating on the basis of reversible protonation or deprotonation, whereas the driving force to improve the sensitivity after plasma modifications is unknown. Herein we manage to solve this problem and investigate the sensing mechanism of atmospheric plasma treated PANI for vapor detection of amides using urea as a model. The results from various analytical techniques indicate that the plausible mechanism responsible for the improved sensitivity after plasma treatment is operating through a cyclic transition state formed between the functional groups introduced by plasma treatment and urea. This transition state improved the sensitivity of PANI towards 15 ppm of urea by a factor of 2.4 times compared to the non-treated PANI. This plasma treated PANI is promising for the improvement of the sensitivity and selectivity towards other toxic and carcinogenic amide analytes for gas sensing applications such as improving material processing and controlling food quality. [Figure not available: see fulltext.] © 2016, Higher Education Press and Springer-Verlag Berlin Heidelberg

Hydrothermal Synthesis of Rare-Earth Modified Titania: Influence on Phase Composition, Optical Properties, and Photocatalytic Activity

In order to expand the use of titania indoor as well as to increase its overall performance, narrowing the band gap is one of the possibilities to achieve this. Modifying with rare earths (REs) has been relatively unexplored, especially the modification of rutile with rare earth cations. The aim of this study was to find the influence of the modification of TiO2 with rare earths on its structural, optical, morphological, and photocatalytic properties. Titania was synthesized using TiOSO4 as the source of titanium via hydrothermal synthesis procedure at low temperature (200 °C) and modified with selected rare earth elements, namely, Ce, La, and Gd. Structural properties of samples were determined by X-ray powder diffraction (XRD), and the phase ratio was calculated using the Rietveld method. Optical properties were analyzed by ultraviolet and visible light (UV-Vis) spectroscopy. Field emission scanning electron microscope (FE-SEM) was used to determine the morphological properties of samples and to estimate the size of primary crystals. X-ray photoelectron spectroscopy (XPS) was used to determine the chemical bonding properties of samples. Photocatalytic activity of the prepared photocatalysts as well as the titania available on the market (P25) was measured in three different setups, assessing volatile organic compound (VOC) degradation, NOx abatement, and water purification. It was found out that modification with rare earth elements slows down the transformation of anatase and brookite to rutile. Whereas the unmodified sample was composed of only rutile, La- and Gd-modified samples contained anatase and rutile, and Ce-modified samples consisted of anatase, brookite, and rutile. Modification with rare earth metals has turned out to be detrimental to photocatalytic activity. In all cases, pure TiO2 outperformed the modified samples. Cerium-modified TiO2 was the least active sample, despite having a light absorption tail up to 585 nm wavelength. La- and Gd-modified samples did not show a significant shift in light absorption when compared to the pure TiO2 sample. The reason for the lower activity of modified samples was attributed to a greater Ti3+/Ti4+ ratio and a large amount of hydroxyl oxygen found in pure TiO2. All the modified samples had a smaller Ti3+/Ti4+ ratio and less hydroxyl oxygen