TY - JOUR A1 - Stephan, Ina A1 - Dimke, Thomas A1 - Guterman, R. A1 - Smith, C. A. A1 - Cataldo, V. A. T1 - Antibacterial and degradable thioimidazolium poly(ionic liquid) JF - ACS Sustainable Chemistry and Engineering N2 - New antibacterial agents are urgently required to fight the emergence of antibiotic-resistant bacteria. We recently synthesized the first thioimidazolium ionene, which has antibacterial properties and can degrade in various media. This dual functionality is crucial in order to limit the environmental impact of these biocides. We have found that our polymer is stronger than benzalkonium chloride (BAC) against Pseudomonas aeruginosa and also readily degrades in the presence of base, while remaining stable in acidic environments. These results highlight a new emerging class of antibacterial degradable polymers. KW - Ionic liquid KW - Antibacterial polymer KW - Amphiphilic polymer KW - Thioimidazolium KW - Degradable polymer KW - Polyioinic liquid PY - 2020 DO - https://doi.org/10.1021/acssuschemeng.0c02666 VL - 8 IS - 22 SP - 8419 EP - 8424 PB - ACS Publications AN - OPUS4-50982 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bandow, N. A1 - Aitken, M. D. A1 - Geburtig, Anja A1 - Kalbe, Ute A1 - Piechotta, Christian A1 - Schoknecht, Ute A1 - Simon, Franz-Georg A1 - Stephan, Ina T1 - Using Environmental Simulations to Test the Release of Hazardous Substances from Polymer-Based Products: Are Realism and Pragmatism Mutually Exclusive Objectives? JF - Materials N2 - The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented. KW - Environmental simulations KW - Polymer-based products KW - Artificial weathering KW - Degradation KW - Leaching KW - Soil contact PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509310 DO - https://doi.org/10.3390/ma13122709 SN - 1996-1944 VL - 13 IS - 12 SP - Paper 2709, 22 PB - MDPI CY - Basel, Switzerland AN - OPUS4-50931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Usmani, S. A1 - Voss, L. A1 - Stephan, Ina A1 - Hübert, Thomas A1 - Kemnitz, E. T1 - Improved Durability of Wood Treated with Nano Metal Fluorides against Brown-Rot and White-Rot Fungi JF - Applied Sciences N2 - Low-water soluble metal fluorides such as magnesium fluoride (MgF2) and calcium Fluoride (CaF2) were evaluated for decay protection of wood. Initially, the biocidal efficacy of nano metal fluorides (NMFs) against wood destroying fungi was assessed with an in-vitro agar test. The results from the test showed that agar medium containing MgF2 and CaF2 was more efficient in preventing fungal decay than stand-alone MgF2 or CaF2. These metal fluorides, in their nanoscopic form synthesized using fluorolytic sol-gel synthesis, were introduced into the sapwood of Scots pine and beech wood and then subjected to accelerated ageing by leaching (EN 84). MAS 19F NMR and X-ray micro CT images showed that metal fluorides were present in treated wood, unleached and leached. Decay resistance of Scots pine and beech wood treated with NMFs was tested against Wood destroying fungi Rhodonia placenta and Trametes versicolor in accordance with EN 113. Results revealed that mass losses were reduced to below 3% in wood treated with the combination of MgF2 and CaF2. It is concluded that NMFs provide full protection to wood even after it has been leached and can be used as wood preservatives in outdoor environments. KW - Nanoparticles KW - Fluoride KW - Wood protection KW - Fluorolytic sol-gel synthesis KW - Brown-rot fungi KW - White-rot fungi KW - Basidiomycetes PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543877 DO - https://doi.org/10.3390/app12031727 VL - 12 IS - 3 SP - 1 EP - 11 PB - MDPI AN - OPUS4-54387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Redfern, J. A1 - Tucker, J. A1 - Simmons, L. A1 - Askew, P. A1 - Verran, J. A1 - Stephan, Ina T1 - Environmental and experimental factors affecting efficacy testing on nonporous plastic antimicrobial surfaces JF - Methods and Protocols N2 - Test methods for efficacy assessment of antimicrobial coatings are not modelled on a hospital environment, and instead use high humidity (>90%) high temperature (37 ◦C), and no airflow. Therefore, an inoculum will not dry, resulting in an antimicrobial surface exhibiting prolonged antimicrobial activity, as moisture is critical to activity. Liquids will dry quicker in a hospital ward, resulting in a reduced antimicrobial efficacy compared to the existing test, rendering the test results artificially favourable to the antimicrobial claim of the product. This study aimed to assess how hospital room environmental conditions can affect the drying time of an inoculum, and to use this data to inform test parameters for antimicrobial efficacy testing based on the hospital ward. The drying time of different droplet sizes, in a range of environmental conditions likely found in a hospital ward, were recorded (n = 630), and used to create a model to inform users of the experimental conditions required to provide a drying time similar to what can be expected in the hospital ward. Drying time data demonstrated significant (p < 0.05) variance when humidity, temperature, and airflow were assessed. A mathematical model was created to select environmental conditions for in vitro antimicrobial efficacy testing. Drying time in different environmental conditions demonstrates that experimental set-ups affect the amount of time an inoculum stays wet, which in turn may affect the efficacy of an antimicrobial surface. This should be an important consideration for hospitals and other potential users, whilst future tests predict efficacy in the intended end-use environment. KW - Method development KW - Standardisation KW - Antimicrobial test KW - Environmental conditions KW - Hospital premises PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472699 DO - https://doi.org/10.3390/mps1040036 SN - 2409-9279 VL - 1 IS - 4 SP - 36, 1 EP - 10 PB - MDPI CY - Internet open accsess AN - OPUS4-47269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guterman, R. A1 - Miao, H. A1 - Cataldo, V. A. A1 - Antonietti, M. A1 - Dimke, Thomas A1 - Stephan, Ina T1 - Thioimidazolium salts as a platform for nonvolatile alkylators and degradable antiseptics JF - ACS sustainable chemistry and engineering N2 - ABSTRACT: A collection of thioimidazolium salts were synthesized and used as a new class of nonvolatile alkylating agents. Their nonvolatility prevents exposure during use or handling and are thus drastically safer than conventional alkylating agents. We discovered that thioimidazolium Iodide salts cannot release volatile compounds in the solid state, but instead only decompose when molten. Since decomposition proceeds via alkyl iodide elimination, SN2 of iodide on the thioimidazolium cation is constrained in the solid state, and instead can occur only upon melting when ions are mobile. By smart design of these alkylators, the melting point and thus the decomposition temperature of these salts can be increased from 106 to 169 °C and release negligible volatile organic compounds prior to melting. Thioimidazolium-bis(trifluoromethanesulfonyl)imide (TFSI) ionic liquids act as a completely nonvolatile and air-stable TFSI-based alkylating agent and can be used for high-throughput Synthesis of TFSI ionic liquids without solvent. Alkyl groups from methyl to dodecyl can be transferred to a nucleophile and the product purified by sublimation of the thione byproduct, which can then be recycled. We also found that thioimidazolium salts with a dodecyl chain are bactericidal, yet can hydrolyze in water to form benign neutral products, and thus wont accumulate in the environment. These results demonstrate that thioimidazolium salts are a designable platform for the pursuit of safer and more environmentally friendly alkylating and antiseptic agents. KW - Alkylating agents KW - Decomposition point KW - Melting point KW - Nonvolatile KW - One-step ionic liquids synthesis KW - Antiseptic agents PY - 2018 DO - https://doi.org/10.1021/acssuschemeng.8b03874 SN - 2168-0485 VL - 6 IS - 11 SP - 15434 EP - 15440 PB - American Chemical Society CY - Washington, DC AN - OPUS4-46904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Usmani, Shirin A1 - Stephan, Ina A1 - Huebert, Thomas A1 - Kemnitz, E. T1 - Nano metal fluorides for wood protection against fungi JF - ACS Applied Nano Materials N2 - Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives. KW - Brown-rot fungi KW - Coniophora puteana KW - Fluoride nanoparticles KW - Fluorolytic sol−gel KW - Rhodonia placenta KW - SEM wood characterization KW - Wood protection PY - 2018 DO - https://doi.org/10.1021/acsanm.8b00144 SN - 2574-0970 VL - 2018 SP - 1 EP - 6 PB - American Chemical Society (ACS) CY - Washington DC, US AN - OPUS4-44730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brischke, C. A1 - Bollmus, S. A1 - Melcher, E. A1 - Stephan, Ina T1 - Biological durability and moisture ynamics of Dawn redwood (Metasequoia glyptostroboides) and Port Orford cedar (Chamaecyparis lawsoniana) JF - Wood Material Science and Engineering N2 - Numerous non-native tree species are given attention with respect to the reforestation of calamity areas in Europe. Among them, several species may form durable wood which can be used for outdoor applications, but differences in wood durability are expected between original and European growth sites. This study aimed at examining the biological durability against wooddestroying fungi and water permeability of German-grown Dawn redwood (Metasequoia glyptostroboides) and Port Orford cedar (Chamaecyparis lawsoniana). The heartwood of both wood species was assigned to durability class 4 (DC 4, less durable) in soil contact and DC 1–4 (very to less durable) against wood-destroying basidiomycetes. However, according to the Meyer-Veltrup model, their material resistance dose was notably higher compared to the reference species Norway spruce (Picea abies), and the resulting service life of above ground structures should be a multiple of the reference. KW - Natural durability KW - Fungal decay KW - Moisture performance KW - Permeability KW - Resistance model KW - Water uptake PY - 2022 DO - https://doi.org/10.1080/17480272.2022.2101941 SN - 1748-0272 SP - 1 EP - 11 PB - Taylor & Francis CY - London AN - OPUS4-55490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barkeshli, Mandana A1 - Stephan, Ina A1 - Shevchuk, Ivan A1 - Soltani, Mojtaba T1 - Characteristics of Sizing Materials Used in Persian Medieval Manuscripts: Physical, Optical, Spectral Imaging, and Fungicidal Properties JF - Studies in Conservation N2 - In this study, we investigated the diverse range of materials used for sizing in Iranian paper manuscripts during the Timurid (fifteenth century) to Safavid (sixteenth century) and Qajar (nineteenth century) periods. Our approach combined historical analysis with scientific examination of reconstructed sizings. We reconstructed 15 sizing materials based on identified Persian historical recipes and analysed their physical, optical, and spectral characteristics. Additionally, we assessed their behaviour against the mould fungus Aspergillus flavus. The results revealed distinctive properties for each sizing material, shedding light on their potential applications in paper preservation. Furthermore, our investigation demonstrated variations in hygroscopicity, thickness, grammage, and ash content post-sizing. The sizing materials also exhibited different effects on paper reflectance properties. Additionally, our study revealed insights into the impact of sizing on burnished papers, indicating that the mechanical process of burnishing did not significantly alter the chemical composition or spectral properties of the paper, with only minor changes in brightness observed in specific cases. All tested sizing materials supported varying levels of mould growth, indicating potential implications for paper conservation. Our findings provide valuable insights into the historical practices of Iranian paper sizing and offer practical considerations for the preservation of paper manuscripts. KW - Paper sizings KW - Persian historical recipes KW - Physical and optical characteristics KW - Fungicidal property KW - Spectral imaging PY - 2024 DO - https://doi.org/10.1080/00393630.2024.2342647 SP - 1 EP - 18 PB - Informa UK Limited AN - OPUS4-60159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -