TY - JOUR A1 - Kettner, Marie Therese A1 - Oberbeckmann, Sonja A1 - Labrenz, Matthias A1 - Grossart, Hans-Peter T1 - The Eukaryotic Life on Microplastics in Brackish Ecosystems JF - Frontiers in Microbiology N2 - Microplastics (MP) constitute a widespread contaminant all over the globe. Rivers and wastewater treatment plants (WWTP) transport annually several million tons of MP into freshwaters, estuaries and oceans, where they provide increasing artificial surfaces for microbial colonization. As knowledge on MP-attached communities is insufficient for brackish ecosystems, we conducted exposure experiments in the coastal Baltic Sea, an in-flowing river and a WWTP within the drainage basin. While reporting on prokaryotic and fungal communities from the same set-up previously, we focus here on the entire eukaryotic communities. Using high-throughput 18S rRNA gene sequencing, we analyzed the eukaryotes colonizing on two types of MP, polyethylene and polystyrene, and compared them to the ones in the surrounding water and on a natural surface (wood). More than 500 different taxa across almost all kingdoms of the eukaryotic tree of life were identified on MP, dominated by Alveolata, Metazoa, and Chloroplastida. The eukaryotic community composition on MP was significantly distinct from wood and the surrounding water, with overall lower diversity and the potentially harmful dinoflagellate Pfiesteria being enriched on MP. Co-occurrence networks, which include prokaryotic and eukaryotic taxa, hint at possibilities for dynamic microbial interactions on MP. This first report on total eukaryotic communities on MP in brackish environments highlights the complexity of MP-associated biofilms, potentially leading to altered microbial activities and hence changes in ecosystem functions. KW - microeukaryotes KW - plastic-associated biofilms KW - Baltic Sea KW - polyethylene KW - polystyrene KW - diversity profiles KW - network analysis KW - next-generation sequencing Y1 - 2019 U6 - https://doi.org/10.3389/fmicb.2019.00538 SN - 1664-302X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Rychkov, Dmitry A1 - Kuznetsov, Alexey A1 - Rychkov, Andrey T1 - Electret properties of polyethylene and polytetrafluoroethylene films with chemically modified surface JF - IEEE transactions on dielectrics and electrical insulation N2 - This paper investigates the effect of chemical surface modification of polytetrafluoroethylene (PTFE) and low density polyethylene (LDPE) films on their electret properties. PTFE films were subjected to wet treatment with three different chemicals: orthophosphoric acid, tetrabutyl titanate and tetraethoxysilane. The technique based on the principles of molecular layer deposition (MLD) method was used to modify the surface of LDPE films with phosphorus trichloride vapors. The surfaces of the films were then corona charged, and the electret charge stability was studied by means of isothermal and thermally stimulated surface potential decay. Both PTFE and LDPE films, after the surface treatment, displayed a considerable enhancement in the charge stability compared to the virgin samples. It is important to note that the enhancement of the charge stability was achieved in the positively charged PTFE films, a result important to practical applications. We attribute this effect of charge stabilization to the formation of new energetically deep traps on the modified surface. Decrease in molecular mobility, due to attachment of new chemical structures to the surface macromolecules, may also contribute to the overall growth of the charge stability. KW - Electrets KW - surface treatment KW - charge stability KW - charge carrier processes KW - polytetrafluoroethylene KW - polyethylene Y1 - 2011 U6 - https://doi.org/10.1109/TDEI.2011.5704487 SN - 1070-9878 VL - 18 IS - 1 SP - 8 EP - 14 PB - Inst. of Electr. and Electronics Engineers CY - Piscataway ER - TY - JOUR A1 - Rychkov, Dmitry A1 - Gerhard, Reimund A1 - Ivanov, Vadim A1 - Rychkov, Andrey T1 - Enhanced electret charge stability on Polyethylene Films treated with Titanium-Tetrachloride vapor JF - IEEE transactions on dielectrics and electrical insulation N2 - Low-density polyethylene (LDPE) films have been treated with titanium-tetrachloride vapor by means of the molecular-layer-deposition method. It is shown that such a treatment leads to a considerable improvement of the electret properties for both positively and negatively charged films. The temperature stability of the electret homo-charge has been increased by approximately 60 degrees C. At the same time, the temporal stability of charge is also considerably improved. Modified low-density polyethylene films show no "cross-over phenomenon" when charged to higher voltages. Thus, it is now possible to produce electrets from polyethylene films with high initial charge densities, but without a strongly reduced charge stability. The influence of a chemical treatment with titanium-tetrachloride vapor on charge injection from aluminum electrodes into polyethylene films was also investigated. It is found that the interface between an aluminum electrode and a modified LDPE surface layer has different injection properties for positive and negative charges. Electrons can be injected across the modified interface, whereas injection of holes is either very limited or non-existent. KW - Electrets KW - chemical modification KW - surface treatment KW - space-charge stability KW - charge-carrier transport KW - polyethylene KW - low-density polyethylene KW - injection Y1 - 2012 SN - 1070-9878 VL - 19 IS - 4 SP - 1305 EP - 1311 PB - Inst. of Electr. and Electronics Engineers CY - Piscataway ER -