Chemistry, Surfaces, Coatings and Films, Polymers and Plastics, Metals and Alloys
23
Scopus Publications
Scopus Publications
Polyethylene Terephthalate-Based Heat Sealable Packaging Film Without Heat Sealing Layer Yukihiro Kusano, Alexander Leo Bardenstein, Claus Bischoff, Stanislav Landa, Anders Ask Carton Packaging Technology and Science, 2025 The food packaging industry is evolving to meet demands for circularity, cost‐effectiveness, lower carbon footprint and higher production efficiency with polyethylene terephthalate (PET) emerging as a preferred material for packaging. Despite its advantages, PET faces two main challenges in flexible barrier packaging applications, such as flow packs or form‐fill‐seal pouches. First, PET films for flexible packaging often lack adequate moisture and oxygen barriers, limiting their range of applications. Second, the high melting temperature of PET of around 250°C complicates the sealing process, causing deformation and poor‐quality seals. Traditional solutions involve multilayer films, in which PET is laminated with a superior permeation‐barrier layer and a lower melting‐temperature heat‐sealing layer. This results in nonrecyclable packaging, posing sustainability issues. In the present work, PET‐based heat sealable films were developed to address these issues. Specifically, a water‐based organic–inorganic hybrid nanocomposite sol–gel coating was applied to one side of the 23‐μm thick PET film, followed by drying and curing. The thickness of the subsequent coatings was approximately 2.3 μm. The sol–gel's rheological properties allow for a microscopically thin application that hardens into a micrometre‐thick, flexible, transparent and abrasion‐resistant coating with a decomposition temperature well above melting temperature of PET. The wettability of the coating was slightly higher than that of PET. The result of the pencil hardness test indicates tight bonding of the coating to the PET film. Mechanical tests of the coated and uncoated PET indicate that the mechanical properties of the bulk PET were retained after the application and curing of the coating, and the reinforcing effect of the coating was confirmed by the measurement of the Young's moduli and the puncture resistance test. Characterization using Fourier transform infrared spectroscopy confirms that the film contains organo‐silicon compounds and aluminium oxides. Uncoated sides of a pair of PET films were faced and heat‐welded at 250°C, demonstrating significantly reduced deformation around the welding portion. The coating reduced oxygen and water vapour transmission rates by more than a factor of 3 and 4, respectively.
Pigmented Antifouling Coatings for Improved on-Site Inspection Claus Bischoff, Jens Røberg Frandsen, Ian Luna, Les Jackowski Heat Transfer Engineering, 2024 Sol-gel derived antifouling coatings for use in crude oil heat exchangers have been successfully utilized for years. The combination of a very thin and heat conductive coating with low surface energy and low surface roughness in an inert glass ceramic matrix has proven very effective in preventing fouling accumulation and maintaining sustained production. A challenge using very thin and transparent sol-gel coatings is reassuring that the items are actually coated and are correctly applied. For plate heat exchangers, that may only be single side coated, it is important that the unit is assembled correctly, so that the coated side of the heat exchanger plates face the crude oil. Also, for inspection purposes and for estimation of residual lifetime, it is important to be able to establish the quality of the coating efficiently and quickly – also inside individual tubes of a shell and tube heat exchanger. Here we present ongoing coating development of Thermo Coat 200 (TC200), an antifouling coating stable up to 300 °C/572 °F, which is provided with inert and heat stable pigments that allow quick inspection of coating integrity, both before and after operation. Together with procedures for testing coating repellency and substrate adhesion, the pigmented TC200 coating may facilitate the industrial transition to antifouling coatings.
Thin sol-gel coatings for fouling mitigation in shell-and-tube heat exchangers Nace International Corrosion Conference Series, 2017
Development, test and offshore use of a foulina repellent coatina for plate heat exchanaers Society of Petroleum Engineers SPE Bergen One Day Seminar 2014, 2014
Gender and telomere length: Systematic review and meta-analysis Michael Gardner, David Bann, Laura Wiley, Rachel Cooper, Rebecca Hardy, Dorothea Nitsch, Carmen Martin-Ruiz, Paul Shiels, Avan Aihie Sayer, Michelangela Barbieri, Sofie Bekaert, Claus Bischoff, Angela Brooks-Wilson, Wei Chen, Cyrus Cooper, Kaare Christensen, Tim De Meyer, Ian Deary, Geoff Der, Ana Diez Roux, Annette Fitzpatrick, Anjum Hajat, Julius Halaschek-Wiener, Sarah Harris, Steven C. Hunt, Carol Jagger, Hyo-Sung Jeon, Robert Kaplan, Masayuki Kimura, Peter Lansdorp, Changyong Li, Toyoki Maeda, Massimo Mangino, Tim S. Nawrot, Peter Nilsson, Katarina Nordfjall, Giuseppe Paolisso, Fu Ren, Karl Riabowol, Tony Robertson, Goran Roos, Jan A. Staessen, Tim Spector, Nelson Tang, Brad Unryn, Pim van der Harst, Jean Woo, Chao Xing, Mohammad E. Yadegarfar, Jae Yong Park, Neal Young, Diana Kuh, Thomas von Zglinicki, Yoav Ben-Shlomo Experimental Gerontology, 2014
Entrapment of subtilisin in ceramic sol-gel coating for antifouling applications Viduthalai Rasheedkhan Regina, Helmer Søhoel, Arcot Raghupathi Lokanathan, Claus Bischoff, Peter Kingshott, Niels Peter Revsbech, Rikke Louise Meyer ACS Applied Materials and Interfaces, 2012 Enzymes with antifouling properties are of great interest in developing nontoxic antifouling coatings. A bottleneck in developing enzyme-based antifouling coatings is to immobilize the enzyme in a suitable coating matrix without compromising its activity and stability. Entrapment of enzymes in ceramics using the sol-gel method is known to have several advantages over other immobilization methods. The sol-gel method can be used to make robust coatings, and the aim of this study was to explore if sol-gel technology can be used to develop robust coatings harboring active enzymes for antifouling applications. We successfully entrapped a protease, subtilisin (Savinase, Novozymes), in a ceramic coating using a sol-gel method. The sol-gel formulation, when coated on a stainless steel surface, adhered strongly and cured at room temperature in less than 8 h. The resultant coating was smoother and less hydrophobic than stainless steel. Changes in the coating's surface structure, thickness and chemistry indicate that the coating undergoes gradual erosion in aqueous medium, which results in release of subtilisin. Subtilisin activity in the coating increased initially, and then gradually decreased. After 9 months, 13% of the initial enzyme activity remained. Compared to stainless steel, the sol-gel-coated surfaces with active subtilisin were able to reduce bacterial attachment of both Gram positive and Gram negative bacteria by 2 orders of magnitude. Together, our results demonstrate that the sol-gel method is a promising coating technology for entrapping active enzymes, presenting an interesting avenue for enzyme-based antifouling solutions.
Quantification of bacteria on abiotic surfaces by laser scanning cytometry: An automated approach to screen the antifouling properties of new surface coatings Viduthalai Rasheedkhan Regina, Morten Poulsen, Helmer Søhoel, Claus Bischoff, Rikke Louise Meyer Journal of Laboratory Automation, 2012 Bacterial biofilms are a persistent source of contamination, and much effort has been invested in developing antifouling surfaces or coatings. A bottleneck in developing such coatings is often the time-consuming task of screening and evaluating a large number of surface materials. An automated high-throughput assay is therefore needed. In this study, we present a promising technique, laser scanning cytometry (LSC), for automated quantification of bacteria on surfaces. The method was evaluated by quantifying young Staphylococcus xylosus biofilms on glass surfaces using LSC and comparing the results with cell counts obtained by fluorescence microscopy. As an example of application, we quantified bacterial adhesion to seven different sol-gel-based coatings on stainless steel. The surface structure and hydrophobicity of the coatings were analyzed using atomic force microscopy and water contact angle measurements. Among the coatings tested, a significant reduction in adhesion of S. xylosus was observed only for one coating, which also had a unique surface microstructure. LSC was particularly sensitive for quantification at low cell densities, and the adhered bacteria could be quantified both as cell number and as area coverage. The method proved to be an excellent alternative to microscopy for fast and reproducible quantification of microbial colonization on abiotic surfaces.
Biofilm retention on surfaces with variable roughness and hydrophobicity Lone Tang, Saju Pillai, Niels Peter Revsbech, Andreas Schramm, Claus Bischoff, Rikke Louise Meyer Biofouling, 2011 Biofilms on food processing equipment cause food spoilage and pose a hazard to consumers. The bacterial community on steel surfaces in a butcher's shop was characterized, and bacteria representative of this community enriched from minced pork were used to study biofilm retention. Stainless steel (SS) was compared to two novel nanostructured sol-gel coatings with differing hydrophobicity. Surfaces were characterized with respect to roughness, hydrophobicity, protein adsorption, biofilm retention, and community composition of the retained bacteria. Fewer bacteria were retained on the sol-gel coated surfaces compared to the rougher SS. However, the two sol-gel coatings did not differ in either protein adsorption, biofilm retention, or microbial community composition. When polished to a roughness similar to sol-gel, the SS was colonized by the same amount of bacteria as the sol-gel, but the bacterial community contained fewer Pseudomonas cells. In conclusion, biofilm retention was affected more by surface roughness than chemical composition under the condition described in this study.
Influence of New Sol-Gel refractory coating on the casting properties of cold box and furan cores for Grey cast iron 69th World Foundry Congress 2010 Wfc 2010, 2010
Telomere length among the elderly and oldest-old Claus Bischoff, Jesper Graakjaer, Hans Christian Petersen, Bernard Jeune, Vilhelm A. Bohr, Steen Koelvraa, Kaare Christensen Twin Research and Human Genetics, 2005
Investigation of the molecular defects in premature aging syndromes: Functional analysis of the sequence-related CSB and WRN proteins FASEB Journal, 1997
