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  • 51.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Blomberg, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    In the Search for Nanospecific Effects of Dissolution of Metallic Nanoparticles at Freshwater-Like Conditions: A Critical Review2019Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, nr 8, s. 4030-4044Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Knowledge on relations between particle properties and dissolution/transformation characteristics of metal and metal oxide nanoparticles (NPs) in freshwater is important for risk assessment and product development. This critical review aims to elucidate nanospecific effects on dissolution of metallic NPs in freshwater and similar media. Dissolution rate constants are compiled and analyzed for NPs of silver (Ag), copper (Cu), copper oxide/hydroxide (CuO, Cu(OH) 2 ), zinc oxide (ZnO), manganese (Mn), and aluminum (Al), showing largely varying (orders of magnitude) constants when modeled using first order kinetics. An effect of small primary sizes (<15 nm) was observed, leading to increased dissolution rate constants and solubility in some cases. However, the often extensive particle agglomeration can result in reduced nanospecific effects on dissolution and also an increased uncertainty related to the surface area, a parameter that largely influence the extent of dissolution. Promising ways to model surface areas of NPs in solution using fractal dimensions and size distributions are discussed in addition to nanospecific aspects related to other processes such as corrosion, adsorption of natural organic matter (NOM), presence of capping agents, and existence of surface defects. The importance of the experimental design on the results of dissolution experiments of metal and metal oxide NPs is moreover highlighted, including the influence of ionic metal solubility and choice of particle dispersion methodology.

  • 52.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Fransson, K.
    Prideaux, Sonja
    Roos, S.
    Jönsson, C.
    Odnevall Wallinder, Inger
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Improving the life cycle impact assessment of metal ecotoxicity: Importance of chromium speciation, water chemistry, and metal release2019Inngår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, nr 6, artikkel-id 1655Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Investigations of metal ecotoxicity in life cycle assessment (LCA) and life cycle impact assessment (LCIA) are becoming important tools for evaluating the environmental impact of a product or process. There is, however, improvement needed for LCIA of metal ecotoxicity in order to make this assessment more relevant and robust. In this work, three issues within the LCIA of metal ecotoxicity are investigated, mainly focusing on topics related to stainless steel manufacturing. The first issue is the importance of considering regional water chemistry when constructing the characterization factor (CF). A model freshwater of relevance for stainless steel manufacturing in a region of Sweden was created with chemistry different from available options. The second issue is related to the lack of consideration on changes in speciation of Cr(VI) in freshwater for a given emission, as Cr(VI) to some extent will be reduced to Cr(III). Two new options are suggested based on relationships between the Cr(VI)-total Cr ratio as a way to improve the relevancy of LCIA for Cr(VI) in freshwater. The last issue is how to treat metal release from slags in LCIA. Metal release from slags was shown to vary significantly between different ways of modelling slag emissions (differences in total metal content, slag leaching tests, estimated emissions to groundwater). 

  • 53.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chaudhary, Himanshu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Wei, Zheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Lendel, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Synergistic effects of metal-induced aggregation of human serum albumin2019Inngår i: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 173, s. 751-758Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Exposure to cobalt (Co), chromium (Cr), and nickel (Ni) occurs often via skin contact and from different dental and orthopedic implants. The metal ions bind to proteins, which may induce structural changes and aggregation, with different medical consequences. We investigated human serum albumin (HSA) aggregation in the presence of Co-II, Cr-III, and/or Ni-II ions and/or their nanoparticle precipitates by using scattering, spectroscopic, and imaging techniques, at simulated physiological conditions (phosphate buffered saline - PBS, pH 7.3) using metal salts that did not affect the pH, and at HSA:metal molar ratios of up to 1:8. Co ions formed some solid nano particles in PBS at the investigated conditions, as determined by nanoparticle tracking analysis, but the Cr-III anions and Ni-II ions remained fully soluble. It was found that all metal ions induced HSA aggregation, and this effect was significantly enhanced when a mixture of all three metal ions was present instead of any single type of ion. Thus, the metal ions induce aggregation synergistically. HSA aggregates formed linear structures on a mica surface in the presence of Cr-III ions. A clear tendency of aggregation and linearly aligned aggregates was seen in the presence of all three metal ions. Spectroscopic investigations indicated that the majority of the HSA molecules maintained their alpha helical secondary structure and conformation. This study highlights the importance of synergistic effects of metal ions and/or their precipitates on protein aggregation, which are highly relevant for implant materials and common exposures to metals.

  • 54.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Erfani, Behnaz
    Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Matura, Mihály
    Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden ; Unit of Occupational and Environmental Dermatology, Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden.
    Lidén, Carola
    Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
    Chromium(III) release from chromium-tanned leather elicits allergic contact dermatitis: a use test study.2018Inngår i: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 78, nr 5, s. 307-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Chromium (Cr) is a common skin sensitizer. The use of Cr(VI) in leather is restricted in the EU, but that of Cr(III) is not.

    OBJECTIVES: To assess whether prolonged exposure to Cr-tanned leather with mainly Cr(III) release may elicit allergic contact dermatitis in Cr-allergic individuals.

    METHOD: Ten Cr-allergic subjects and 22 controls were patch tested with serial dilutions of Cr(III) and Cr(VI), and with leather samples. They then conducted a use test with a Cr-tanned and a Cr-free leather bracelet over a period of 3 weeks, for 12 h per day. Cr deposited on the skin from the bracelets was measured in the controls, and the diphenylcarbazide test for Cr(VI) and extraction tests for Cr(III) and Cr(VI) were conducted for the different leathers.

    RESULTS: Four of 10 Cr-allergic subjects developed positive reactions to the Cr-tanned bracelet within 7-21 days, whereas only 1 of 10 had a positive patch test reaction to this leather. Cr released from the Cr-tanned leather was most probably entirely Cr(III), with a quantifiable amount being deposited on the skin.

    CONCLUSIONS: This study strongly suggests that prolonged and repeated exposure to Cr-tanned leather with mainly Cr(III) release is capable of eliciting allergic contact dermatitis in Cr-allergic individuals.

  • 55.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Uter, Wolfgang
    Univ Erlangen Nurnberg, Dept Med Informat Biometry & Epidemiol, Erlangen, Germany..
    Banerjee, Piu
    Guys Hosp, St Johns Inst Dermatol, London, England.;Lewisham & Greenwich NHS Trust, London, England..
    Lind, Marie-Louise
    Stockholm Cty Council, Ctr Occupat & Environm Med, Stockholm, Sweden..
    Steengaard, Sanne Skovvang
    Univ Hosp Herlev Gentofte, Natl Allergy Res Ctr, Hellerup, Denmark..
    Teo, Ying
    Guys Hosp, St Johns Inst Dermatol, London, England..
    Liden, Carola
    Karolinska Inst, Inst Environm Med, Box 210, SE-17177 Stockholm, Sweden..
    Non-oxidative hair dye products on the European market: What do they contain?2018Inngår i: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 79, nr 5, s. 281-287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Hair dyeing is very common and may cause allergic contact dermatitis. Oxidative (often termed permanent or semi-permanent) hair dye products have constituted the focus of market surveys and toxicological risk assessments, while non-oxidative (semi-permanent, temporary or direct) products have not been assessed. Objectives: To identify the hair dye substances presently used in non-oxidative hair dye products in Europe. Methods: Ingredient label data on eligible products in 5 European countries were collected, and 289 different non-oxidative hair dye products were included in this study. Results: Up to 9 hair dye substances were present in each product. Sixty-eight individual hair dye substances were identified on the 289 product labels, and their occurrence ranged from 0.3% to 34%. There were differences concerning substances used and their number per product between products of different consistency and colour. Conclusions: The hair dye substances in non-oxidative hair dye products are different from those in oxidative hair dye products, and are currently not covered by patch test series. The toxicological and skin-sensitizing profile of the substances in non-oxidative hair dye products, as well as their concentrations, should be further investigated.

  • 56.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Wei, Zheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chevez, Federico Moncada
    Natl Autonomous Univ Honduras, Dept Publ Hlth, Fac Med Sci, Tegucigalpa, Honduras.;Cent Amer Network Informat & Advice Ctr Toxicol R, Tegucigalpa, Honduras.;Ctr Res & Dev Hlth Labour & Environm CIDSTA, Tegucigalpa, Honduras..
    Chromium(III), chromium(VI) and cobalt release from leathers produced in Nicaragua2019Inngår i: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 80, nr 3, s. 149-155Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Leather exposure has been associated with chromium (Cr) and cobalt (Co) contact dermatitis. Cr(VI) in leather is now restricted to < 3 mg/kg in the EU. Cr(III) is not restricted. Objectives: To analyse 29 differently coloured Cr-tanned leather samples from two Nicaraguan tanneries, and to compare their release of Cr, Cr(VI) and Co with that of leathers produced in Europe. Methods: Cr, Cr(VI) and Co were extracted in phosphate buffer for 3 hours at 25 degrees C according to EN ISO 17075. Atomic absorption spectroscopy and spectrophotometry were used for detection of the metals in phosphate buffer. Results: There was no difference in total Cr or Cr(VI) release between European and Nicaraguan leathers. There was no association between Cr(VI) and total Cr release. Co was released primarily from leathers of one tannery. Cr(III) was released in significantly higher amounts than Cr(VI). Conclusions: Future investigations and regulations should focus on Cr(III) and Co as well as on Cr(VI).

  • 57.
    Hedberg, Yolanda
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Znidarsic, Monika
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Univ Ljubljana, Fac Chem & Chem Technol, Vecna Pot 113, SI-1000 Ljubljana, Slovenia.
    Herting, Gunilla
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Milosev, Ingrid
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Mechanistic insight on the combined effect of albumin and hydrogen peroxide on surface oxide composition and extent of metal release from Ti6Al4V2019Inngår i: Journal of Biomedical Materials Research - Part B Applied Biomaterials, ISSN 1552-4973, Vol. 107, nr 3, s. 858-867Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The titanium–aluminium (6 wt%)–vanadium (4 wt%) (Ti6Al4V) alloy is widely used as an orthopedic and dental implant material due to its high corrosion resistance in such environments. The corrosion resistance is usually determined by means of electrochemical methods, which may not be able to detect other chemical surface reactions. Literature findings report a synergistic effect of the combination of the abundant protein albumin and hydrogen peroxide (H 2 O 2 ) on the extent of metal release and corrosion of Ti6Al4V. The objectives of this study were to gain further mechanistic insight on the interplay of H 2 O 2 and albumin on the metal release process of Ti6Al4V with special focus on (1) kinetics and (2) H 2 O 2 and albumin concentrations. This was accomplished mainly by metal release and surface oxide composition investigations, which confirmed the combined effect of H 2 O 2 and albumin on the metal release process, although not detectable by electrochemical open circuit potential measurements. A concentration of 30 mM H 2 O 2 induced substantial changes in the surface oxide characteristics, an oxide which became thicker and enriched in aluminum. Bovine serum albumin (BSA) seemed to be able to deplete this aluminum content from the outermost surface or at least to delay its surface enrichment. This effect increased with increased BSA concentration, and for time periods longer than 24 h. This study hence suggests that short-term (accelerated) corrosion resistance measurements are not sufficient to predict potential health effects of Ti6Al4V alloys since also chemical dissolution mechanisms play a large role for metal release, possibly in a synergistic way.

  • 58.
    Hermanowska, Malgorzata
    et al.
    Univ Southern Denmark, Dept Phys & Chem, Odense M, Denmark.;Univ Southern Denmark, MEMPHYS, Odense M, Denmark..
    Bijelic, Goran
    KTH, Skolan för kemivetenskap (CHE).
    Ciobanasu, Corina
    Univ Bonn, Inst Phys & Theoret Chem, Bonn, Germany..
    Kubitscheck, Ulrich
    Univ Bonn, Inst Phys & Theoret Chem, Bonn, Germany..
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Klosgen, Beate M.
    Univ Southern Denmark, Dept Phys & Chem, Odense M, Denmark.;Univ Southern Denmark, MEMPHYS, Odense M, Denmark..
    Charges in phospholipid layers2009Inngår i: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 96, nr 3, s. 18A-18AArtikkel i tidsskrift (Annet vitenskapelig)
  • 59.
    Herting, Gunilla
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Maria-Elisa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    A novel method to assess mass loss of aluminium in concrete2018Inngår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 69, nr 12, s. 1811-1814Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel pickling procedure for aluminium is elaborated for successful removal of corrosion products on aluminium embedded and exposed in concrete, allowing subsequent mass loss evaluation. The current recommended standard procedures for mass loss evaluation of aluminium are not sufficiently effective, either leaving significant amounts of concrete and corrosion products on the aluminium surfaces after pickling, or containing hazardous chemicals. Removal of both concrete and corrosion products from the aluminium surfaces require a stepwise combination of an aqueous glycine solution, nitric acid at elevated temperature and careful manual removal of adherent concrete.

  • 60.
    Hjalmarsson, Nicklas
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Attana AB, Stockholm, SE-11419, Sweden.
    Bergendal, Erik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Attana AB, Stockholm, SE-11419, Sweden.
    Wang, Yong-Lei
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Munavirov, Bulat
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Wallinder, Daniel
    Attana AB, SE-11419 Stockholm, Sweden..
    Glavatskih, Sergei
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.). Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University, Ghent, B-9000, Belgium.
    Aastrup, Teodor
    Attana AB, SE-11419 Stockholm, Sweden..
    Atkin, Rob
    Univ Western Australia, Sch Mol Sci, Perth, WA 6009, Australia..
    Furo, Istvan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Rutland, Mark W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Surfaces, Processes and Formulation, RISE Research Institutes of Sweden, Stockholm, SE-50115, Sweden.
    Electro-Responsive Surface Composition and Kinetics of an Ionic Liquid in a Polar Oil2019Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, nr 48, s. 15692-15700Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The quartz crystal microbalance (QCM) has been used to study how the interfacial layer of an ionic liquid dissolved in a polar oil at low weight percentages responds to changes in applied potential. The changes in surface composition at the QCM gold surface depend on both the magnitude and sign of the applied potential. The time-resolved response indicates that the relaxation kinetics are limited by the diffusion of ions in the interfacial region and not in the bulk, since there is no concentration dependence. The measured mass changes cannot be explained only in terms of simple ion exchange; the relative molecular volumes of the ions and the density changes in response to ion exclusion must be considered. The relaxation behavior of the potential between the electrodes upon disconnecting the applied potential is more complex than that observed for pure ionic liquids, but a measure of the surface charge can be extracted from the exponential decay when the rapid initial potential drop is accounted for. The adsorbed film at the gold surface consists predominantly of ionic liquid despite the low concentration, which is unsurprising given the surtactant-like structures of (some of) the ionic liquid ions. Changes in response to potential correspond to changes in the relative numbers of cations and anions, rather than a change in the oil composition. No evidence for an electric field induced change in viscosity is observed. This work shows conclusively that electric potentials can be used to control the surface composition, even in an oil-based system, and paves the way for other ion solvent studies.

  • 61.
    Hore, Dennis K.
    et al.
    Univ Victoria, Dept Chem, Victoria, BC V8W 3V6, Canada..
    Tyrode, Eric
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Probing Charged Aqueous Interfaces Near Critical Angles: Effect of Varying Coherence Length2019Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, nr 27, s. 16911-16920Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Angle-resolved vibrational sum frequency generation experiments have been used to study the silica-water interface as a function of ionic strength. Well below the critical angle, the sum frequency intensity increases up to 10(-4) M NaCl and then drops. However, near the critical angle, a plateau may be observed up to 10(-4) M. We first demonstrate that this is a result of the interaction of a long Debye length at low ionic strength with a long coherence length near the critical angles. In order to account for the behavior at the lowest concentrations where surface potentials are typically large, it is necessary to consider an electrostatic potential that extends into the bulk aqueous phase beyond the Debye-Huckel approximation. Because the extent of second- and third-order contributions to the nonlinear polarization can vary with ionic strength, but not with the angle of incidence, we perform a global fit to the experimental data using our proposed model to extract the relative magnitude of the two susceptibilities. The ionic strength dependence of this ratio points to the critical nature of the silanol deprotonation and the development of surface charge and illustrates how surface water molecules respond. These results highlight the importance of varying the coherence length in order to probe the water structure at charged interfaces.

  • 62. Hosseinpour, S.
    et al.
    Leygraf, Christopher
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Gretic, Z. H.
    Mioc, E. K.
    Curkovic, H. O.
    Bochmann, S.
    Bachmann, J.
    Waegner, V.
    Virtanen, S.
    Peukert, W.
    Self-assembled monolayers as corrosion inhibitors; indoor, marine and biologically relevant exposure2017Inngår i: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers , 2017Konferansepaper (Fagfellevurdert)
  • 63.
    Hägg Mameng, Sukanya
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Localised corrosion and atmospheric corrosion of stainless steels2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This research is focused on defining limiting conditions for corrosion of stainless steels. The aim of the first part (Papers I-IV) was to understand the role of alloying level and environmental parameters on localised corrosion in aqueous conditions. Testing was done with a combination of short-term electrochemical and long-term immersion experiments. Results show that the chloride ion concentration and temperature are the main factors that affect the localised corrosion resistance. The presence of residual chlorine is also significant, since it leads to the ennoblement of the corrosion potential. If the corrosion potential exceeds the breakdown potential, the stainless steel will suffer from localised corrosion. Oxygen content and pH were identified as additional factors influencing the corrosivity of the environment.

    The aim of second part (Papers V-VIII) was to present information about the effect of alloying level, surface condition and environmental conditions on atmospheric corrosion resistance in Middle-East environments. Field exposure tests were performed and supplemented by laboratory aqueous corrosion tests. Results demonstrate that a higher alloying level (in both the bulk material and the surface), plus a smoother and cleaner surface gave an improvement in the corrosion performance and resistance to aesthetic degradation. Chloride and sulphate are the main surface contaminants found in the Middle East atmosphere. Stainless steels exposed in sheltered conditions showed a better atmospheric corrosion resistance than in open conditions. Three factors are considered to contribute to this difference: a very low rainfall, more condensation leading to corrosion in the open conditions and a higher level of beneficial sulphate in the deposits in sheltered conditions. The results showed a reasonable correlation between laboratory pitting corrosion tests and atmospheric field tests.

    The results from this thesis provide reference data to aid selection of appropriate stainless steel grades. Results can also be used to help understand the limits for use of stainless steels in different conditions in both aqueous environments and in the atmosphere.

  • 64.
    Hägg Mameng, Sukanya
    et al.
    Avesta Research Center, Outokumpu Stainless AB, Avesta, Sweden.
    Pettersson, Rachel
    Jernkontoret, The Swedish Steel Producers’ Association Stockholm, Stockholm, Sweden.
    Leygraf, Christopher
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Wegrelius, Lena
    Avesta Research Center, Outokumpu Stainless AB, Avesta, Sweden.
    Atmospheric Corrosion Resistance of Stainless Steel: Results of a Field Exposure Program in the Middle-East2016Inngår i: Berg- und Huttenmännische Monatshefte (BHM), ISSN 0005-8912, E-ISSN 1613-7531, Vol. 161, nr 1, s. 33-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Stainless steels have been widely used as architectural and construction materials because of their high degree of corrosion resistance, unique aesthetic quality, and stability in an unpolluted atmosphere. Although stainless steel is highly corrosion resistant, localized corrosion can occur in certain environments, especially in marine atmospheric conditions if the appropriate grade is not used. Exposure of stainless steel to an environment more aggressive than the limiting conditions may be harmful to its aesthetic appearance and ultimately even to its load-bearing capacity. Selecting a suitable stainless steel grade requires knowledge of the actual location of the application and the atmospheric conditions. In terms of materials selection, the austenitic stainless steel grade 316/316L has proved a very popular choice for architectural applications in many locations, but it is not always suitable at demanding sites such as marine environments in the Middle-East. In such cases the use of a higher-performance grade, often in combination with a good surface finish and established cleaning routines, is required to maintain pristine surfaces.

    The main objective of this paper is to present information about the atmospheric corrosion resistance of a number of stainless steels in the Middle-East at a marine site. The results obtained are analysed and discussed in terms of factors affecting atmospheric corrosion of stainless steel such as the, alloying element level, surface roughness, surface treatment, and microclimate.

  • 65.
    Hägg Mameng, Sukanya
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pettersson, RachelLeygraf, ChristopherKTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.Wegrelius, Lena
    Effect of surface finishes on the atmospheric corrosion of duplex grade UNS S32205: results of a field exposure program in Dubai2016Konferanseproceedings (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The duplex grade UNS S32205 is an excellent choice in many marine environments where UNS S31603 is on the borderline in regards to atmospheric corrosion resistance. The properties of S32205 make it well suited for construction with respect to strength, reduced maintenance, durability and long-term service. In marine environments the use of a sufficiently highly alloyed stainless steel, often in combination with a good surface finish and adequate maintenance, is required to maintain pristine surfaces.

    The main objective with this paper is to present information about the effect of different surface finishes on the corrosion and aesthetic appearance of the duplex grade S32205 exposed at a marine test site in Dubai, UAE. The results obtained include the effect of characteristics such as surface roughness, surface treatment and surface orientation after several years of exposure. Results show that duplex grade UNS S32205 can be considered for architectural materials in severe marine locations such as the Dubai site. A smooth surface and an appropriate surface treatment give improved corrosion resistance. Chromium and silicon in the passive film were found to be beneficial in terms of resistance to aesthetic degradation. A correlation was observed between aqueous corrosion resistance measured in laboratory pitting corrosion tests and the atmospheric field test results.

  • 66. Jin, Ying
    et al.
    Lai, Zhaogui
    Bi, Peng
    Yan, Songtao
    Wen, Lei
    Wang, Yongchao
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Combining lithography and capillary techniques for local electrochemical property measurements2018Inngår i: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 87, s. 53-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The relationships between composition, microstructure and electrochemical properties are of fundamental importance in understanding the corrosion of multiphase materials and thus in aiding in the design of new materials. A local electrochemical test system which combines a capillary device with a photolithographic mask has been developed to investigate the local electrochemical properties of a predefined micron-sized area with greater reliability and versatility than existing approaches. Independent electrochemical measurements were conducted on the different phases of a 2205 duplex stainless steel in NaCl solution, demonstrating the feasibility of the developed test system.

  • 67.
    Judith Cruz, M.
    et al.
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Makarova, Irina V.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS.;Lappeenranta Univ Technol, Sch Engn Sci, Dept Separat & Purificat, Skinnarilankatu 34, FI-53850 Lappeenranta, Finland..
    Kharitonov, Dmitry S.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS.;Polish Acad Sci, Jerzy Haber Inst Catalysis & Surface Chem, Krakow, Poland..
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chernik, Alexander A.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS..
    Grageda, Mario
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Ushak, Svetlana
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Corrosion properties of nickel coatings obtained from aqueous and nonaqueous electrolytes2019Inngår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 51, nr 9, s. 943-953Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nickel was deposited on a copper substrate from aqueous and nonaqueous ethanol electrolytes. X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and chronovoltametry, scanning electron microscopy, and atomic force microscopy were used to study the effect of the solvent on the surface and corrosion properties of the Ni coatings formed. Unifom and relatively smooth Ni films were obtained as measured with microscopy techniques. The formation of a passive film in acidic, alkaline, and neutral chloride-containing media was confirmed with X-ray photoelectron spectroscopy. The water-based nickel-plating electrolyte makes it possible to deposit coatings with higher corrosion resistance as compared with coatings deposited from ethanol electrolyte in NaOH and NaCl media. The proposed mechanism of corrosion in a 0.5 M H2SO4 solution involves cycles of active-passive surface behavior due to its passivation by corrosion products.

  • 68.
    Kaestner, Bernd
    et al.
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Johnson, C. Magnus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Hermann, Peter
    PTB, Abbestr 2-12, D-10587 Berlin, Germany.;Deutschland GmbH & Co KG, West Pharmaceut Serv, Stolberger Str 21-41, D-52249 Eschweiler, Germany..
    Kruskopf, Mattias
    PTB, Bundesallee 100, D-38116 Braunschweig, Germany.;NIST, 100 Bur Dr, Gaithersburg, MD 20899 USA..
    Pierz, Klaus
    PTB, Bundesallee 100, D-38116 Braunschweig, Germany..
    Hoehl, Arne
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Hornemann, Andrea
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Ulrich, Georg
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Fehmel, Jakob
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Patoka, Piotr
    Free Univ Berlin, Inst Chem & Biochem, Phys Chem, Takustr 3, D-14195 Berlin, Germany..
    Ruehl, Eckart
    Free Univ Berlin, Inst Chem & Biochem, Phys Chem, Takustr 3, D-14195 Berlin, Germany..
    Ulm, Gerhard
    PTB, Abbestr 2-12, D-10587 Berlin, Germany..
    Infrared Nanospectroscopy of Phospholipid and Surfactin Monolayer Domains2018Inngår i: ACS OMEGA, ISSN 2470-1343, Vol. 3, nr 4, s. 4141-4147Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A main challenge in understanding the structure of a cell membrane and its interactions with drugs is the ability to chemically study the different molecular species on the nanoscale. We have achieved this for a model system consisting of mixed monolayers (MLs) of the biologically relevant phospholipid 1,2-distearoyl-sn-glycero-phosphatidylcholine and the antibiotic surfactin. By employing nano-infrared (IR) microscopy and spectroscopy in combination with atomic force microscopy imaging, it was possible to identify and chemically detect domain formation of the two constituents as well as to obtain IR spectra of these species with a spatial resolution on the nanoscale. A novel method to enhance the near-field imaging contrast of organic MLs by plasmon interferometry is proposed and demonstrated. In this technique, the organic layer is deposited on gold and ML graphene substrates, the latter of which supports propagating surface plasmons. Plasmon reflections arising from changes in the dielectric environment provided by the organic layer lead to an additional contrast mechanism. Using this approach, the interfacial region between surfactin and the phospholipid has been mapped and a transition region is identified.

  • 69.
    Kanerva, M.
    et al.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland.;Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Besharat, Zahra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Parnanen, T.
    Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Jokinen, J.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Honkanen, M.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Sarlin, E.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Göthelid, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Schlenzka, D.
    Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Miniature CoCr laser welds under cyclic shear: Fatigue evolution and crack growth2019Inngår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 99, s. 93-103Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Miniature laser welds with the root depth in the range of 50-300 pm represent air-tight joints between the components in medical devices, such as those in implants, growth rods, stents and various prostheses. The current work focuses on the development of a fatigue test specimen and procedure to determine fatigue lives of shear-loaded laser welds. A cobalt-chromium (CoCr) alloy is used as a benchmark case. S-N graphs, damage process, and fracture surfaces are studied by applying x-ray analysis, atomic force microscopy, and scanning electron microscopy both before and after the crack onset. A non-linear material model is fitted for the CoCr alloy to run finite element simulations of the damage and deformation. As a result, two tensile-loaded specimen designs are established and the performance is compared to that of a traditional torque-loaded specimen. The new generation specimens show less variation in the determined fatigue lives due to well-defined crack onset point and, therefore, precise weld seam load during the experiments. The fatigue damage concentrates to the welded material and the entire weld experiences fatigue prior to the final, fracture-governed failure phase. For the studied weld seams of hardened CoCr, a regression fatigue limit of 10.8-11.8 MPa, where the stress refers to the arithmetic average shear stress computed along the region dominated by shear loading, is determined.

  • 70.
    Kanerva, M.
    et al.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland. Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Besharat, Zahra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pärnänen, T.
    Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Jokinen, J.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Honkanen, M.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Sarlin, E.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Göthelid, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Schlenzka, D.
    Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Automatization and stress analysis data of CoCr laser weld fatigue tests2019Inngår i: Data in Brief, E-ISSN 2352-3409, Vol. 26, artikkel-id 104374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work includes raw and analyzed test data when using a recently developed fatigue test method for miniature laser welds in cobalt-chromium (CoCr) alloy joints [1]: 10.1016/j.jmbbm.2019.07.004. The automization of fatigue tests is crucial for saving costs and personnel resources and that is the reason why the atomization threshold and the resulting spectrum data related to CoCr welds are provided here. The finite element method based stress computation output is provided related to shearing-mode tests to support the dataset as a whole. In addition, the compositional data of the parent material and the laser weld are given.

  • 71.
    Kawada, S.
    et al.
    Japan.
    Watanabe, Seiya
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Sasaki, S.
    Japan.
    Miyatake, M.
    Japan.
    Evaluation of friction behavior and surface interactions of cyano-based ionic liquids under different sliding contacts and high vacuum condition2018Inngår i: Lubricants, ISSN 2075-4442, Vol. 6, nr 3, artikkel-id 69Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The friction coefficients of ionic liquids were evaluated by many investigations. Most investigations used fluorine-based ionic liquids as lubricants. However, these ionic liquids produce the corrosion wear. This investigation focuses on the use of cyano-based ionic liquids as lubricants. Compared to fluorine-based ionic liquids, cyano-based ionic liquids exhibit high friction coefficients against steel material. This work examines how the friction coefficients of cyano-based ionic liquids are influenced by the type of sliding material used (AISI 52100, TiO2, and tetrahedral amorphous carbon). TiO2 lubricated with 1-ethyl-3-methylimidazolium tricyanomethanide, and ta-C lubricated with 1-butyl-1methylpyrrolidinium tetracyanoborate exhibited very low friction coefficients, smaller than fluorine-based ionic liquids. Time-of-Flight Secondary Ion Mass Spectrometry analysis showed that anions adsorb onto the worn surface, suggesting that anion adsorption is a critical parameter influencing friction coefficients. Quadrupole Mass Spectrometry measurements revealed that cations decompose on the nascent surface, preventing adsorption on the worn surface. These results suggest that low friction coefficients require the decomposition of cations and adsorption of anions. The reactivity of nascent surface changes with the sliding material used due to varying catalytic activity of the nascent surfaces.

  • 72. Kawada, S.
    et al.
    Watanabe, Seiya
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Tadokoro, C.
    Sasaki, S.
    Effects of Alkyl Chain Length of Sulfate and Phosphate Anion-Based Ionic Liquids on Tribochemical Reactions2018Inngår i: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 66, nr 1, artikkel-id 8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ionic liquids are expected to become increasingly popular lubricants as they feature a number of attractive properties. This investigation focused on sulfate and phosphate anion-based ionic liquids and the improvement in lubricating performance with the addition of these anions. However, the detailed lubricating mechanism and effect of alkyl chain length on tribochemical reactions are unclear. This study investigates tribochemical reaction processes using a quadrupole mass spectrometer (Q-MS) and X-ray photoelectron spectroscopy. Seven types of ionic liquids: 1-ethyl-3-methylimidazolium hydrogensulfate ([EMIM][HSO4]), 1-ethyl-3-methylimidazolium methylsulfate ([EMIM][MSU]), 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][ESU]), 1-ethyl-3-methylimidazolium n-octylsulfate ([EMIM][OSU]), 1-ethyl-3-methylimidazolium dimethyl phosphate ([EMIM][DMP]), 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][DEP]), and 1-ethyl-3-methylimidazolium dibutyl phosphate ([EMIM][DBP]), were selected as lubricants. The friction coefficient of sulfate anion-based ionic liquids increased as their alkyl chain lengthened. However, wear scar diameter in this case showed the opposite tendency. The friction coefficient and wear scar diameter of phosphate anion-based ionic liquids increased with an increase in the alkyl chain length. Q-MS results indicated that the main outgassing components during sliding were the cation components, whereas the anion remained on the sliding surface and formed a tribofilm. The ionic liquids with short alkyl chains reacted with the sliding surface easily and led to very low friction. However, corrosive wear occurred in the case of the sulfate anion. On the other hand, anions with long alkyl chains underwent gradual tribochemical reactions because that led the mitigation of contact with nascent surface. The phosphate-based ionic liquids with long alkyl chains were unable to cause the lubricating effect due to low reactivity.

  • 73. Kawada, S.
    et al.
    Watanabe, Seiya
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Tadokoro, C.
    Tsuboi, R.
    Sasaki, S.
    Lubricating mechanism of cyano-based ionic liquids on nascent steel surface2018Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 119, s. 474-480Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates the lubricating mechanism of cyano-based ionic liquids on steel surfaces using Q-MS, ToF-SIMS, and TGA. [EMIM][DCN], [EMIM][TCC], [EMIM][TCB], [BMPL][DCN], [BMPL][TCC], and [BMPL][TCB] were selected as lubricants. [EMIM][TCB] exhibited the highest friction coefficient. The others exhibited very low friction coefficients of less than 0.08. Q-MS analysis indicated that the cation components were detected in outgassing during sliding tests. However, anion components were not detected. ToF-SIMS results showed that the anions remained on the worn surfaces which would lead low friction coefficients. To achieve low friction coefficient, the tribo-decomposition of the ionic liquids and adsorption of anion were required. TGA indicated thermal stability was an index for tribo-decomposition on the nascent steel surface.

  • 74. Kawada, Shouhei
    et al.
    Sato, Keisuke
    Watanabe, Seiya
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Sasaki, Shinya
    Lubricating property of cyano-based ionic liquids against hard materials2017Inngår i: Journal of Mechanical Science and Technology, ISSN 1738-494X, E-ISSN 1976-3824, Vol. 31, nr 12, s. 5745-5750Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ionic liquids are expected to be used as a new lubricants and lubricant additives because of their unique properties. However, cyano-based ionic liquids have exhibited poor lubricating property with steel/steel contacts. We evaluated the lubricating properties of cyano-based ionic liquids with steel/hard materials contacts. TiO2, Al2O3, and tetrahedral amorphous carbon (ta-C) DLC were used as hard materials. Six types of ionic liquids, as combination of two types of cations ([EMIM], [BMPL]) and three types of cyanide anions ([DCN], [TCC] and [TCB]), were selected. In sliding tests of steel/TiO2 and steel/Al2O3 lubricated with [EMIM][DCN], [BMPL][DCN], [EMIM][TCC], [BMPL][TCC] exhibited low friction coefficients of less than 0.1. In addition, steel/Al2O3 and steel/ta-C DLC lubricated with [BMPL][TCB] exhibited very low friction coefficients less than 0.05. On the other hand, high friction coefficients were observed at steel/TiO2 and steel/Al2O3 contacts lubricated with [EMIM][TCB] and steel/ta-C DLC contact lubricated with [EMIM] cation group. Peeling of the ta-C DLC was observed when [EMIM] cation group was used. ToF-SIMS analysis indicated that the anion was adsorbed on the worn surfaces in the case of low frictional conditions. However, both ions were hardly observed in the case of high frictional conditions. It is considered that the ionic liquids underwent tribo-decomposition on the worn surfaces at low friction coefficient. To evaluate the degree of tribo-decomposition, Thermogravimetric analysis (TGA) was used. TGA results indicated that [EMIM][TCB], which exhibited high friction coefficient, had the most highest stability among all ionic liquids. Low stability ionic liquids, however, showed a tendency for low friction coefficient. These results suggest that lubricating properties are related to the stability of ionic liquids.

  • 75.
    Kharitonov, Dmitry S.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Sommertune, Jens
    RISE Res Inst Sweden, Surface Proc & Formulat, SE-11486 Stockholm, Sweden..
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Ryl, Jacek
    Gdansk Univ Technol, Dept Electrochem Corros & Mat Engn, 11-12 Narutowicza St, PL-80233 Gdansk, Poland..
    Kurilo, Irina I.
    Belarusian State Technol Univ, Organ Subst Technol Fac, Dept Phys Colloid & Analyt Chem, Minsk 220006, BELARUS..
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Corrosion inhibition of aluminium alloy AA6063-T5 by vanadates: Local surface chemical events elucidated by confocal Raman micro-spectroscopy2019Inngår i: CORROSION SCIENCE, Vol. 148, s. 237-250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemical interactions between aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions. Confocal Raman and X-ray photoelectron spectroscopy experiments were utilised to gain insight into the mechanism of corrosion inhibition by vanadates. A greenish-grey coloured surface layer, consisting of V+4 and V+5 polymerized species, was seen to form on the alloy surface, especially on top of cathodic micrometre-sized IMPs, whereby suppressing oxygen reduction kinetics. The results suggest a two-step mechanism of corrosion inhibition in which V+5 species are first reduced to V+4 or V+3 species above cathodic IMPs, and then oxidized to mixed-valence V+5/V+4 polymerized compounds.

  • 76.
    Kharitonov, Dmitry S.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Electrochem Prod Technol & Mat Elect Eq, Minsk 220006, BELARUS..
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Swerea KIMAB, Dept Corros Energy & Proc Ind, SE-16440 Kista, Sweden..
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Sommertune, Jens
    RISE Res Inst Sweden, Chem Mat & Surfaces, SE-11486 Stockholm, Sweden..
    Zharskii, Ivan M.
    Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Electrochem Prod Technol & Mat Elect Eq, Minsk 220006, BELARUS..
    Kurilo, Irina I.
    Belarusian State Technol Univ, Organ Subst Technol Fac, Dept Phys Colloid & Analyt Chem, Minsk 220006, BELARUS..
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Corrosion Inhibition of Aluminum Alloy AA6063-T5 by Vanadates: Microstructure Characterization and Corrosion Analysis2018Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, nr 3, s. C116-C126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Corrosion inhibition of aluminum alloy AA6063-T5 by vanadates (NaVO3) in 0.05 M NaCl solution has been investigated by electrochemical and weight loss measurements, and associated with microstructure and Volta potential data. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy analyses confirmed the presence of micrometer-sized Fe-rich Al4.01MnSi0.74, Al1.69Mg4Zn2.31, and FeAl3 intermetallic phases (IMPs) and nanometer-sized CuAl2, ZnAl2, and Mg2Si precipitates in the microstructure. Scanning Kelvin probe force microscopy measurements showed Volta potential differences of up to 600 mV between the microstructure constituents indicating a high susceptibility to micro-galvanic corrosion, with interphase boundary regions exhibiting the highest propensity to corrosion. Most IMPs had cathodic character whereas some nanometer-sized Mg-rich particles exhibited anodic nature, with large Volta potential gradients within interphase regions of large cathodic particles. Electrochemical potentiodynamic polarization measurements indicated that the vanadates provided mixed corrosion inhibition effects, mitigating both oxygen reduction, occurring on cathodic IMPs, and anodic metal dissolution reaction, occurring on anodic sites, such as Mg2Si and interphase boundary regions. Electrochemical measurements indicated that the sodium metavanadate inhibitor blocks active metal dissolution, giving high inhibition efficiency (>95%) during the initial exposure, whereas long-term weight loss measurements showed that the efficacy decreases after prolonged exposure.

  • 77. Kocabaş, M.
    et al.
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Curioni, M.
    Cansever, N.
    Nickel fluoride as a surface activation agent for electroless nickel coating of anodized AA1050 aluminum alloy2019Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 364, s. 231-238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, the use of nickel fluoride tetrahydrate (NiF 2 ·4H 2 O) as a surface activator and sealant at the same time for the coating of electroless nickel-phosphorus (Ni-P) on anodized aluminum alloy AA1050 is proposed. The usage of the activator resulted in more efficient deposition of Ni-P, improved adhesion properties, and increased wear and friction behavior as opposed to non-activated conditions. Scanning electron microscopy (SEM) and confocal laser microscopy (CLM) analyses of ultramicrotome-cut cross sections of Ni-P coated specimens, surface-activated by NiF 2 ·4H 2 O, revealed a more well-structured metal-coating interface as opposed to non-activated conditions.

  • 78.
    Koppolu, Rajesh
    et al.
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland..
    Abitbol, Tiffany
    RISE Res Inst Sweden, Biosci & Mat Surface Proc & Formulat, S-11428 Stockholm, Sweden..
    Kumar, Vinay
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland.;Finland Ltd, VTT Tech Res Ctr, High Performance Fiber Prod, Espoo 02044, Finland..
    Jaiswal, Aayush Kumar
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland..
    Swerin, Agne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. RISE Res Inst Sweden, Biosci & Mat Surface Proc & Formulat, S-11428 Stockholm, Sweden..
    Toivakka, Martti
    Abo Akad Univ, Lab Paper Coating & Converting, Ctr Funct Mat, SF-20500 Turku, Finland..
    Continuous roll-to-roll coating of cellulose nanocrystals onto paperboard2018Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 10, s. 6055-6069Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is an increased interest in the use of cellulose nanocrystal (CNC) films and coatings for a range of functional applications in the fields of material science, biomedical engineering, and pharmaceutical sciences. Most of these applications have been demonstrated on films and coatings produced using laboratory-scale batch processes, such as solvent casting, dip coating, or spin coating. For successful coating application of CNC suspensions using a high throughput process, several challenges need to be addressed: relatively high viscosity at low solids content, coating brittleness, and potentially poor adhesion to the substrate. This work aims to address these problems. The impact of plasticizer on suspension rheology, coating adhesion, and barrier properties was quantified, and the effect of different pre-coatings on the wettability and adhesion of CNC coatings to paperboard substrates was explored. CNC suspensions were coated onto pre-coated paperboard in a roll-to-roll process using a custom-built slot die. The addition of sorbitol reduced the brittleness of the CNC coatings, and a thin cationic starch pre-coating improved their adhesion to the paperboard. The final coat weight, dry coating thickness, and coating line speed were varied between 1-11 g/m(2), 900 nm-7 A mu m, and 2.5-10 m/min, respectively. The barrier properties, adhesive strength, coating coverage, and smoothness of the CNC coatings were characterized. SEM images show full coating coverage at coat weights as low as 1.5 g/m(2). With sorbitol as plasticizer and at coat weights above 3.5 g/m(2), heptane vapor and water vapor transmission rates were reduced by as much as 99% and 75% respectively. Compared to other film casting techniques, the process employed in this work deposits a relatively thick coating in significantly less time, and may therefore pave the way toward various functional applications based on CNCs. [GRAPHICS] .

  • 79.
    Koppolu, Rajesh
    et al.
    Abo Akad Univ, Ctr Funct Mat, Lab Paper Coating & Converting, SF-20500 Turku, Finland..
    Lahti, Johanna
    Tampere Univ Technol, Paper Converting & Packaging, Tampere 33100, Finland..
    Abitbol, Tiffany
    RISE Res Inst Sweden, Bioecon Biorefinery & Energy, S-11428 Stockholm, Sweden..
    Swerin, Agne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Kuusipalo, Jurkka
    Tampere Univ Technol, Paper Converting & Packaging, Tampere 33100, Finland..
    Toivakka, Martti
    Abo Akad Univ, Ctr Funct Mat, Lab Paper Coating & Converting, SF-20500 Turku, Finland..
    Continuous Processing of Nanocellulose and Polylactic Acid into Multilayer Barrier Coatings2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 12, s. 11920-11927Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent years have seen an increased interest toward utilizing biobased and biodegradable materials for barrier packaging applications. Most of the abovementioned materials usually have certain shortcomings that discourage their adoption as a preferred material of choice. Nanocellulose falls into such a category. It has excellent barrier against grease, mineral oils, and oxygen but poor tolerance against water vapor, which makes it unsuitable to be used at high humidity. In addition, nanocellulose suspensions' high viscosity and yield stress already at low solid content and poor adhesion to substrates create additional challenges for high-speed processing. Polylactic acid (PLA) is another potential candidate that has reasonably high tolerance against water vapor but rather a poor barrier against oxygen. The current work explores the possibility of combining both these materials into thin multilayer coatings onto a paperboard. A custom-built slot-die was used to coat either microfibrillated cellulose or cellulose nanocrystals onto a pigment-coated baseboard in a continuous process. These were subsequently coated with PLA using a pilot-scale extrusion coater. Low-density polyethylene was used as for reference extrusion coating. Cationic starch precoating and corona treatment improved the adhesion at nanocellulose/baseboard and nanocellulose/PLA interfaces, respectively. The water vapor transmission rate for nanocellulose + PLA coatings remained lower than that of the control PLA coating, even at a high relative humidity of 90% (38 degrees C). The multilayer coating had 98% lower oxygen transmission rate compared to just the PLA-coated baseboard, and the heptane vapor transmission rate reduced by 99% in comparison to the baseboard. The grease barrier for nanocellulose + PLA coatings increased 5-fold compared to nanocellulose alone and 2-fold compared to PLA alone. This approach of processing nanocellulose and PLA into multiple layers utilizing slot-die and extrusion coating in tandem has the potential to produce a barrier packaging paper that is both 100% biobased and biodegradable.

  • 80.
    Kottwitz, Matthew
    et al.
    Univ Illinois, Dept Chem, 1209 W Calif St, Urbana, IL 61801 USA..
    Li, Yuanyuan
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA..
    Palomino, Robert M.
    Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Liu, Zongyuan
    Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Wang, Guangjin
    Hubei Engn Univ, Coll Chem & Mat Sci, Xiaogan 432000, Peoples R China.;Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Peoples R China..
    Wu, Qin
    Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA..
    Huang, Jiahao
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA..
    Timoshenko, Janis
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA..
    Senanayake, Sanjaya D.
    Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Balasubramanian, Mahalingam
    Argonne Natl Lab, Adv Photon Source, Lemont, IL 60439 USA..
    Lu, Deyu
    Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA..
    Nuzzo, Ralph G.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Univ Illinois, Dept Chem, 1209 W Calif St, Urbana, IL 61801 USA..
    Frenkel, Anatoly I.
    SUNY Stony Brook, Dept Mat Sci & Chem Engn, Stony Brook, NY 11794 USA.;Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA..
    Local Structure and Electronic State of Atomically Dispersed Pt Supported on Nanosized CeO22019Inngår i: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 9, nr 9, s. 8738-8748Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single atom catalysts (SACs) have shown high activity and selectivity in a growing number of chemical reactions. Many efforts aimed at unveiling the structure-property relationships underpinning these activities and developing synthesis methods for obtaining SACs with the desired structures are hindered by the paucity of experimental methods capable of probing the attributes of local structure, electronic properties, and interaction with support-features that comprise key descriptors of their activity. In this work, we describe a combination of experimental and theoretical approaches that include photon and electron spectroscopy, scattering, and imaging methods, linked by density functional theory calculations, for providing detailed and comprehensive information on the atomic structure and electronic properties of SACs. This characterization toolbox is demonstrated here using a model single atom Pt/CeO2 catalyst prepared via a sol-gel-based synthesis method. Isolated Pt atoms together with extra oxygen atoms passivate the (100) surface of nanosized ceria. A detailed picture of the local structure of Pt nearest environment emerges from this work involving the bonding of isolated Pt2+ ions at the hollow sites of perturbed (100) surface planes of the CeO2 support, as well as a substantial (and heretofore unrecognized) strain within the CeO2 lattice in the immediate vicinity of the Pt centers. The detailed information on structural attributes provided by our approach is the key for understanding and improving the properties of SACs.

  • 81.
    Kozhuharov, Svilen
    et al.
    Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Radiom, Milad
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Maroni, Plinio
    Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Borkovec, Michal
    Univ Geneva, Dept Inorgan & Analyt Chem, Sci 2, 30 Quai Ernest Ansermet, CH-1205 Geneva, Switzerland..
    Persistence Length of Poly(vinyl amine): Quantitative Image Analysis versus Single Molecule Force Response2018Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 51, nr 10, s. 3632-3639Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single molecules of poly(vinyl amine) are analyzed in the adsorbed state by atomic force microscopy (AFM) in two different ways. First, high-resolution images of individual adsorbed polymers were recorded in monovalent electrolyte solutions. The backbone of the imaged polymers was digitized, and the directional correlation function and internal mean-square end-to-end distance were evaluated. These quantities were analyzed with the wormlike chain (WLC) model, and the persistence length was extracted. Second, individual polymer chains were picked up from the surface, and their force extension behavior was recorded in the same electrolyte solutions. These force profiles were also interpreted in terms of the WLC model, whereby the elastic contribution was also considered. Both techniques yield the persistence length of the polymer. From imaging one obtains a persistence length of about 1.6 nm, while the force experiments yield a value around 0.51 nm. We suspect that the force experiments reflect the intrinsic part of the persistence length, while the imaging experiments yield the persistence length including the electrostatic

  • 82.
    Lebedova, Jana
    et al.
    Karolinska Inst, Inst Environm Med, Nobels Vag 13, S-17177 Stockholm, Sweden.;Masaryk Univ, RECETOX, Kamenice 753-5,Pavilon A29, CZ-62500 Brno, Czech Republic..
    Hedberg, Yolanda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Hanna L.
    Karolinska Inst, Inst Environm Med, Nobels Vag 13, S-17177 Stockholm, Sweden..
    Size-dependent genotoxicity of silver, gold and platinum nanoparticles studied using the mini-gel comet assay and micronucleus scoring with flow cytometry2018Inngår i: Mutagenesis, ISSN 0267-8357, E-ISSN 1464-3804, Vol. 33, nr 1, s. 77-85Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metallic nanoparticles (NPs) are promising nanomaterials used in different technological solutions as well as in consumer products. Silver (Ag), gold (Au) and platinum (Pt) represent three metallic NPs with current or suggested use in different applications. Pt is also used as vehicle exhaust catalyst leading to a possible exposure via inhalation. Despite their use, there is limited data on their genotoxic potential and possible size-dependent effects, particularly for Pt NPs. The aim of this study was to explore size-dependent genotoxicity of these NPs (5 and 50 nm) following exposure of human bronchial epithelial cells. We characterised the NPs and assessed the viability (Alamar blue assay), formation of DNA strand breaks (mini-gel comet assay) and induction of micronucleus (MN) analysed using flow cytometry (in vitro microflow kit). The results confirmed the primary size (5 and 50 nm) but showed agglomeration of all NPs in the serum free medium used. Slight reduced cell viability (tested up to 50 mu g/ml) was observed following exposure to the Ag NPs of both particle sizes as well as to the smallest (5 nm) Au NPs. Similarly, at non-cytotoxic concentrations, both 5 and 50 nm-sized Ag NPs, as well as 5 nm-sized Au NPs, increased DNA strand breaks whereas for Pt NPs only the 50 nm size caused a slight increase in DNA damage. No clear induction of MN was observed in any of the doses tested (up to 20 mu g/ml). Taken together, by using the comet assay our study shows DNA strand breaks induced by Ag NPs, without any obvious differences in size, whereas effects from Au and Pt NPs were size-dependent in the sense that the 5 nm-sized Au NPs and 50 nm-sized Pt NPs particles were active. No clear induction of MN was observed for the NPs.

  • 83. Lee, Jookyeong
    et al.
    Choi, Eun Jung
    Varga, Imre
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Yun, Sang-Ho
    Song, Changsik
    Terpyridine-functionalized stimuli-responsive microgels and their assembly through metal-ligand interactions2018Inngår i: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 9, nr 8, s. 1032-1039Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We developed a terpyridine-functionalized microgel (tpy-mG) for its supramolecular assembly. Tpy-mG was synthesized by amidation between 3-(4-([2,2':6',2 ''-terpyridin]-4'-yl)phenoxy) propan-1-amine and carboxylates of a thermo-responsive p(NIPAM-co-MAA) microgel (A-mG), which was synthesized by emulsion polymerization. After decorating terpyridine, its effects on the hydrodynamic radius, volume phase transition temperature (VPTT), and the colloidal stability of the microgel were investigated. Tpy-mG can be assembled reversibly with several metal ions (Ni2+, Fe2+, Co2+, or Zn2+), and interestingly the assembled tpy-mG-M2+ showed different rheological properties depending on the metal ion type; the weakly bound ions (Co2+, Zn2+) indicated fast dynamics for "inter-particular" exchange, resulting in much higher storage (G') and loss (G '') moduli. Photocatalysts such as Ru dyes can be easily introduced into tpy-mG via metal-ligand interactions, and the photooxidation of benzylamine was tested. The free Ru dye showed almost the same conversions at 25 and 50 degrees C, whereas the assembled Ru-tpy-mG-Mg2+ displayed reduced conversion at 50 degrees C (>VPTT). This is suggested to be due to the collapsed or "locked" structure around the photocatalytic center (Ru). Tpy-mG can be utilized as a good platform for developing responsive functional materials via reversible metal-ligand complexation.

  • 84.
    Leygraf, Christopher
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chang, Tingru
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Herting, Gunilla
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    The origin and evolution of copper patina colour2019Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 157, s. 337-346Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The copper patina colour has been systematically explored through a large set of short- and long-term exposed copper metal samples. The initial brown-black appearance is attributed to semiconducting properties of cuprite (Cu2O) and fully attained at thickness 0.8 +/- 0.2 mu m. The characteristic green-blue appearance is due to the colour forming Cu(II)-ion in the outer patina layer which needs to be 12 +/- 2 mu m to fully cover the inner cuprite layer. No significant influence of atmospheric environment on patina colour is discerned. The green-blue patina colour on historic copper was attained after shorter exposures than in modem copper due to more inhomogeneous microstructure.

  • 85.
    Li, Gen
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Salazar-Sandoval, Eric Johansson
    RISE Res Inst Sweden, Div Biosci & Mat, Box 5607, SE-11486 Stockholm, Sweden..
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. RISE Res Inst Sweden, Div Biosci & Mat, Box 5607, SE-11486 Stockholm, Sweden..
    Load-dependent surface nanomechanical properties of poly-HEMA hydrogels in aqueous medium2019Inngår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 15, nr 38, s. 7704-7714Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanical properties of hydrogels are of importance in many applications, including scaffolds and drug delivery vehicles where the release of drugs is controlled by water transport. While the macroscopic mechanical properties of hydrogels have been reported frequently, there are less studies devoted to the equally important nanomechanical response to local load and shear. Scanning probe methods offer the possibility to gain insight on surface nanomechanical properties with high spatial resolution, and thereby provide fundamental insights on local material property variations. In this work, we investigate the local response to load and shear of poly(2-hydroxyethyl methacrylate) hydrogels with two different cross-linking densities submerged in aqueous solution. The response of the hydrogels to purely normal loads, as well as the combined action of load and shear, was found to be complex due to viscoelastic effects. Our results show that the surface stiffness of the hydrogel samples increased with increasing load, while the tip-hydrogel adhesion was strongly affected by the load only when the cross-linking density was low. The combined action of load and shear results in the formation of a temporary sub-micrometer hill in front of the laterally moving tip. As the tip pushes against such hills, a pronounced stick-slip effect is observed for the hydrogel with low cross-linking density. No plastic deformation or permanent wear scar was found under our experimental conditions.

  • 86.
    Li, Hua
    et al.
    Univ Western Australia, Sch Mol Sci, 35 Stirling Highway, Perth, WA 6009, Australia.;Univ Western Australia, Ctr Microscopy Characterisat & Anal, Perth, WA 6009, Australia..
    Choi, Yu Suk
    Univ Western Australia, Sch Human Sci, 35 Stirling Highway, Perth, WA 6009, Australia..
    Rutland, Mark W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Rise.
    Atkin, Rob
    Univ Western Australia, Sch Mol Sci, 35 Stirling Highway, Perth, WA 6009, Australia..
    Nanotribology of hydrogels with similar stiffness but different polymer and crosslinker concentrations2020Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 563, s. 347-353Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hypothesis: The stiffness has been found to regulate hydrogel performances and applications. However, the key interfacial properties of hydrogels, like friction and adhesion are not controlled by the stiffness, but are altered by the structure and composition of hydrogels, like polymer volume fraction and crosslinking degree. Experiments: Colloidal probe atomic force microscopy has been use to investigate the relationship between tribological properties (friction and adhesion) and composition of hydrogels with similar stiffness, but different polymer volume fractions and crosslinking degrees. Findings: The interfacial normal and lateral (friction) forces of hydrogels are not directly correlated to the stiffness, but altered by the hydrogel structure and composition. For normal force measurements, the adhesion increases with polymer volume fraction but decreases with crosslinking degree. For lateral force measurements, friction increases with polymer volume fraction, but decreases with crosslinking degree. In the low normal force regime, friction is mainly adhesion-controlled and increases significantly with the adhesion and polymer volume fraction. In the high normal force regime, friction is predominantly load-controlled and shows slow increase with normal force. 

  • 87. Li, Hua
    et al.
    Cooper, Peter
    Somers, A
    Rutland, Mark W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Howlett, Patrick
    Atkin, Rob
    Titania lubrication using oil-ionic liquid mixtures2018Konferansepaper (Fagfellevurdert)
  • 88.
    Li, Jing
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. RISE KIMAB AB, RISE Res Inst Sweden, Div Mat & Prod, S-16440 Kista, Sweden..
    Ecco, Luiz
    Univ Trento, Dept Ind Engn, I-38123 Trento, Italy..
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat Surface Proc & Formulat, SE-11486 Stockholm, Sweden..
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Probing electrochemical mechanism of polyaniline and CeO2 nanoparticles in alkyd coating with in-situ electrochemical-AFM and IRAS2019Inngår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 132, s. 399-408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The corrosion protection and electrochemical mechanism of solvent-borne alkyd composite coating containing 1.0 wt.% polyaniline (PANI) and 1.0 wt.% CeO2 nanoparticles (NPs) for carbon steel in 3.0 wt.% NaCl solution were investigated by means of scanning electron microscopy (SEM), ex-situ, in-situ and electrochemical controlled (EC) atomic force microscopy (AFM), open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) methods. The SEM and ex-situ AFM results revealed the micro- and nanostructure of the composite coating. The in-situ sequential AFM images and line profiling analysis indicated electrochemical activity of the NPs and a high stability of the composite coating in NaCl solution. The results of EC-AFM combined with cyclic voltammetry (CV) demonstrated volume change of the PANI NPs upon reduction and oxidation at certain applied potentials on the coating. The redox reactions between the different forms of PANI and the effect of the CeO2 NPs on the polymerization of the composite polymer were further confirmed by infrared reflection absorption spectroscopy (IRAS). The OCP and EIS results revealed that the composite coating provided an improved corrosion protection for carbon steel within several days of exposure, which was attributed to the barrier protection of CeO2 NPs and the passivation ability of PANI.

  • 89.
    Liu, Min
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    DFT calculations of initial localized corrosion of aluminum: Influence of aqueous ad-layer, chloride ions, and intermetallic particles2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Localized corrosion of aluminum (Al, here including Al alloys) involves a series of physico-chemical processes at the interface between the metal and the aqueous ad-layer or the aqueous solution. The mechanisms that govern localized corrosion are quite complex and have been the subject of many experimental studies. Efforts to improve our understanding through computational studies have so far been much more limited. The primary aim of this Doctoral Thesis was to apply Density Functional Theory (DFT), together with some Molecular Dynamics calculations (limited effort), to gain a deeper mechanistic understanding of some of the most influential factors for the initiation of localized corrosion of Al: chloride ions, intermetallic particles (IMPs) and the presence of an aqueous ad-layer on the solid phase.In the scientific literature three scenarios have been proposed for the interaction of chloride ions with an aluminum and/or passive aluminum surface: through adsorption onto the passive layer, through breakdown of the same layer or through migration of chloride ions into the layer. DFT-calculations have been able to explore these scenarios in more detail, and provide evidence that chloride ions induce partial de-passivation in several ways. On the bare Al surface, chloride ions may inhibit the re-passivation through competitive adsorption with oxygen molecules, as suggested by density of state calculations. Chloride ions are also found to migrate via oxygen vacancies into the inner part of the investigated aluminum oxide films (α- and γ-Al2O3), where a critical amount of accumulated chloride can promote meta-stable pitting propagation. γ-Al2O3 exhibits a more open structure than α-Al2O3, resulting in a lower energy barrier for chloride migration.Micro-galvanic effects induced by Volta potential differences between representative intermetallic particles (Mg2Si and Al2Cu) and the surrounding Al matrix were predicted by calculating the work function of the bare surfaces of these phases with DFT. These values vary with crystalline face orientation and with terminal atomic configuration in the outmost surface layer. Calculated Volta potential differences between IMPs and Al show a reasonable agreement with reported experimental data, and suggest the possibility of predicting the nobility of specific IMPs relative to Al. Moreover, both DFT and scanning Kelvin probe force microscopy show evidence of electrochemical nobility inversion of Mg2Si versus Al upon adsorption of pure water ad-layers. This implies that an originally- 2 -cathodic Mg2Si phase becomes anodic compared to Al upon water adsorption, and is attributed to surface relaxation according to DFT calculations. With subsequent introduction of chloride ions into the water ad-layer, the nobility inversion of both Mg2Si and Al2Cu retains. This is due to a strong oxidizing effect of water on Al, while the effect of chloride seems less pronounced.In all, these and other examples presented show that DFT-calculations can provide more detailed atomistic and molecular information on physico-chemical processes governing localized corrosion of Al than experiments alone can do.

  • 90.
    Liu, Min
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. University of Science and Technology Beijing, National Center for Materials Service Safety.
    Jin, Ying
    University of Science and Technology Beijing, National Center for Materials Service Safety.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    A DFT-Study of Cl Ingress into α-Al2O3(0001) and Al(111) and Its Possible Influence on Localized Corrosion of Al2019Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, nr 11, s. C3124-C3130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ingress of chloride into alpha-Al2O3(0001) and Al(111) was calculated by first-principles theory calculations by considering Cl insertion into Al or O vacancies within alpha-Al2O3(0001) or into vacancy or interstitial sites within Al(111). For alpha-Al2O3, the formation of an O vacancy is energetically more favorable than of an Al vacancy. The insertion of Cl into an O vacancy is also more favorable than into an Al vacancy. A high energy-barrier has been derived for Cl transport within the neighboring O vacancies. In addition, the work function decreases with Cl ingress into the interior of the oxide. For Al(111), Cl insertion into either an Al vacancy or an interstitial site is less favorable compared to the insertion into alpha-Al2O3. The work function only changes slightly with Cl insertion into an Al vacancy. Moreover, the pre-inserted Cl reduces the energy-barrier for further Cl ingress into alpha-Al2O3, whereas Cl tends to stay in the sub-surface layer of Al(111), suggesting Cl accumulation at the Al2O3/Al.

  • 91.
    Liu, Min
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. University of Science and Technology Beijing, National Center for Materials Service Safety.
    Jin, Ying
    University of Science and Technology Beijing, National Center for Materials Service Safety.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Co-adsorption of H2O, OH, and Cl on aluminum and intermetallic surfaces and its effects on the work function studied by DFT calculations2019Inngår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The energetics of adsorption of H2O layers and H2O layers partially replaced with OH or Cl on an Al(111) surface and on selected surfaces of intermetallic phases, Mg2Si and Al2Cu, was studied by first-principle calculations using the density function theory (DFT). The results show that H2O molecules tended to bind to all investigated surfaces with an adsorption energy in a relatively narrow range, between -0.8 eV and -0.5 eV, at increased water coverage. This can be explained by the dominant role of networks of hydrogen bonds at higher H2O coverage. On the basis of the work function, the calculated Volta potential data suggest that both intermetallic phases became less noble than Al(111); also, the Volta potential difference was larger than 1 V when the coverage of the Cl-containing ad-layer reached one monolayer. The energetics of H2O dissociation and substitution by Cl as well as the corresponding work function of each surface were also calculated. The increase in the work function of the Al(111) surface was attributed to the oxidation effect during H2O adsorption, whereas the decrease of the work function for the Mg2Si(111)-Si surface upon H2O adsorption was explained by atomic and electronic rearrangements in the presence of H2O and Cl.

  • 92.
    Liu, Min
    et al.
    University of Science and Technology Beijing, Beijing, 100083, China.
    Jin, Ying
    University of Science and Technology Beijing, National Center for Materials Service Safety.
    Zhang, Chuanhui
    University of Science and Technology Beijing, National Center for Materials Service Safety.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Wen, Lei
    University of Science and Technology Beijing, National Center for Materials Service Safety.
    Density-functional theory investigation of Al pitting corrosion in electrolyte containing chloride ions2015Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 357, s. 2028-2038Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The behavior of chloride ions (Cl-) and oxygen species (the oxygen atom, O or molecular oxygen, O-2) on Al(1 1 1) surface has been studied by density functional theory calculations in order to deepen the molecular understanding of fundamental processes leading to pitting of aluminum (Al). The adsorption behavior of individual species, Cl-, O atom and O-2 was determined first. Subsequently, three possible scenarios in different pitting stages were modeled exploring the repassivation and dissolution of Al in neutral electrolyte containing Cl-. In scenario i, it was found that Cl- can hardly destroy even an O-monolayer on Al(1 1 1) surface, however may lead to the elongation of Al-O bond and the weakened binding between the first Al layer and subsequent Al layers. Both O-2 and Cl- were simultaneously introduced onto Al(1 1 1) in scenario ii. The result showed a weakened Al-O interaction and an intensive hybridization peak at -0.18 Ha between Al-3p with Cl-3p suggesting insufficient repassivation behavior of Al under this condition. Finally, scenario iii mimicked different local environmental conditions in pits formed on Al. At low coverage of Cl-, chloride ions had little effect on surface relaxation. The interaction among chloride ions and Al surface became stronger as Cl- coverage increased. Surface Al atoms dissolved gradually and substructures such as AlCl3 and Al2C15 formed when the coverage was larger than 2/3 ML of a monolayer.

  • 93.
    Långberg, Marie
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. SWERIM, SE-16407 Kista, Sweden..
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Zhang, Fan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Cheng, J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Liu, M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Granaes, E.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Wiemann, C.
    Res Ctr Julich, Peter Grunberg Inst PGI 6, D-52425 Julich, Germany..
    Gloskovskii, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Matveyev, Y.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Kulkarni, S.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Noei, H.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Keller, T. F.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany.;Univ Hamburg, Phys Dept, D-20355 Hamburg, Germany..
    Lindell, D.
    SWERIM, SE-16407 Kista, Sweden..
    Kivisakk, U.
    AB Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Lundgren, E.
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Stierle, A.
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany.;Univ Hamburg, Phys Dept, D-20355 Hamburg, Germany..
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Characterization of Native Oxide and Passive Film on Austenite/Ferrite Phases of Duplex Stainless Steel Using Synchrotron HAXPEEM2019Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, nr 11, s. C3336-C3340Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new measurement protocol was used for microscopic chemical analysis of surface oxide films with lateral resolution of 1 mu m. The native air-formed oxide and an anodic passive film on austenite and ferrite phases of a 25Cr-7Ni super duplex stainless steel were investigated using synchrotron hard X-ray photoemission electron microscopy (HAXPEEM). Pre-deposited Pt-markers, in combination with electron backscattering diffraction mapping (EBSD), allowed analysis of the native oxide on individual grains of the two phases and the passive film formed on the same area after electrochemical polarization of the sample. The results showed a certain difference in the composition of the surface films between the two phases. For the grains with (001) crystallographic face // sample surface, the native oxide film on the ferrite contained more Cr oxide than the austenite. Anodic polarization up to 1000 mV/(Ag/AgCl) in 1M NaCl solution at room temperature resulted in a growth of the Cr- and Fe-oxides, diminish of Cr-hydroxide, and an increased proportion of Fe3+ species. by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.

  • 94.
    MacKenzie, Jordan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Söderberg, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Swerin, Agne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. RISE Research Institutes of Sweden.
    Lundell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Turbulent stress measurements of fibre suspensions in a straight pipe2018Inngår i: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 30, nr 2, artikkel-id 025104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The focus of the present work is an experimental study of the behaviour of semi-dilute, opaque fibre suspensions in fully developed cylindrical pipe flows. Measurements of the normal and turbulent shear stress components and the mean flow were acquired using phase-contrast magnetic resonance velocimetry. Two fibre types, namely, pulp fibre and nylon fibre, were considered in this work and are known to differ in elastic modulus. In total, three different mass concentrations and seven Reynolds numbers were tested to investigate the effects of fibre interactions during the transition from the plug flow to fully turbulent flow. It was found that in fully turbulent flows of nylon fibres, the normal, < u(z)u(z)>(+), and shear, < u(z)u(z)>(+) (note that <.> is the temporal average, u is the fluctuating velocity, z is the axial or streamwise component, and r is the radial direction), turbulent stresses increased with Reynolds number regardless of the crowding number (a concentration measure). For pulp fibre, the turbulent stresses increased with Reynolds number when a fibre plug was present in the flow and were spatially similar in magnitude when no fibre plug was present. Pressure spectra revealed that the stiff, nylon fibre reduced the energy in the inertial-subrange with an increasing Reynolds and crowding number, whereas the less stiff pulp fibre effectively cuts the energy cascade prematurely when the network was fully dispersed.

  • 95. Makarova, I. V.
    et al.
    Kharitonov, D. S.
    Dobryden', Illia B.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chernik, A. A.
    Corrosion Behavior in Acid and Alkaline Media of Nickel Coatings Deposited at Room Temperature2018Inngår i: Russian journal of applied chemistry, ISSN 1070-4272, E-ISSN 1608-3296, Vol. 91, nr 9, s. 1441-1450Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Impedance spectroscopy, chronovoltammetry, chronopotentiometry, scanning electron microscopy, and atomic-force microscopy were used to examine the corrosion behavior in acid and alkaline media and the morphology of nickel coatings electrodeposited from acetate, tartrate, and isobutyrate electrolytes at a temperature of 20–25°C. Models describing the nickel corrosion processes in H2SO4 and NaOH solutions were suggested. It was found that nickel coatings formed from isobutyrate electrolytes have the highest corrosion resistance.

  • 96.
    Makarova, Irina
    et al.
    Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Technol Electrochem Prod & Elect Engn M, Sverdlova Str 13a, Minsk 220006, BELARUS.;LUT Univ, Sch Engn Sci, Dept Separat & Purificat, Yliopistonkatu 34, FI-53850 Lappeenranta, Finland..
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Kharitonov, Dmitry
    Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Technol Electrochem Prod & Elect Engn M, Sverdlova Str 13a, Minsk 220006, BELARUS.;Polish Acad Sci, Jerzy Haber Inst Catalysis & Surface Chem, Niezapominajek 8, PL-30239 Krakow, Poland..
    Kasach, Aliaksandr
    Belarusian State Technol Univ, Chem Technol & Engn Fac, Dept Chem Technol Electrochem Prod & Elect Engn M, Sverdlova Str 13a, Minsk 220006, BELARUS..
    Ryl, Jacek
    Gdansk Univ Technol, Dept Electrochem Corros & Mat Engn, Narutowicza Str 11-12, PL-80233 Gdansk, Poland..
    Repo, Eveliina
    LUT Univ, Sch Engn Sci, Dept Separat & Purificat, Yliopistonkatu 34, FI-53850 Lappeenranta, Finland..
    Vuorinen, Esa
    Lulea Univ Technol, Dept Engn Sci & Math, S-97187 Lulea, Sweden..
    Nickel-nanodiamond coatings electrodeposited from tartrate electrolyte at ambient temperature2019Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 380, artikkel-id 125063Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, nanocrystalline Ni and Ni-diamond coatings were obtained by electrodeposition from tartrate electrolyte at ambient temperature aiming at improving corrosion and wear properties of the material. The created surfaces were investigated with regard to microhardness, adhesion, wear- and corrosion-resistance. The various methods such as atomic force microscopy, scanning electron microscopy, electrochemical impedance spectroscopy and linear polarization technique were applied to study the coating surface properties. The introduction of nanodiamond particles into the coating led to a rougher surface structure and a bigger grain size in comparison to bare nickel coating. Our study shows that the addition of 5.10(-2) (g dm(-3)) of nanodiamonds to the plating bath is enough to obtain composite coatings with a clear increase in microhardness and wear resistance. The slightly improved corrosion resistance of the coating, decrease in corrosion current density from 0.41 to 0.14 mu A cm(-2) in neutral chloride-containing medium, and nobler values of the corrosion potential were also observed.

  • 97.
    Mazo, Juan J.
    et al.
    Univ Zaragoza, Dept Fis Mat Condensada, Zaragoza, Spain.;Univ Zaragoza, CSIC, Inst Ciencia Mat Aragon, Zaragoza, Spain..
    Martinez, Pedro J.
    Univ Zaragoza, CSIC, Inst Ciencia Mat Aragon, Zaragoza, Spain.;Univ Zaragoza, Dept Fis Aplicada, Zaragoza, Spain..
    Pedraz, Patricia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Hennig, Jana
    Friedrich Schiller Univ Jena, Otto Schott Inst Mat Res OSIM, Lobdergraben 32, D-07743 Jena, Germany..
    Gnecco, Enrico
    Friedrich Schiller Univ Jena, Otto Schott Inst Mat Res OSIM, Lobdergraben 32, D-07743 Jena, Germany..
    Plowing-Induced Structuring of Compliant Surfaces2019Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, nr 25, artikkel-id 256101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The structures produced by a sharp tip scraping a compliant surface are modeled in the illustrative case of scan patterns formed by a series of parallel lines. This is made possible by a modified version of the Prandtl model for stick-slip friction, with an interaction energy landscape replicating the morphology of the evolving surface. As a result, a ripple motif emerges with a tilt angle increasing linearly with the distance between the scan lines, except for the region close to the left boundary of the scanned area, where the ripples are oriented at 90 degrees. This region can penetrate considerably to the right, forming a complex branched pattern. These predictions are substantiated by atomic force microscopy nanolithography experiments on polystyrene surfaces at room temperature. A simple and robust theoretical protocol for reproducing early-stage wear processes (potentially going beyond single contacts) is thus made available.

  • 98.
    McCarrick, Sarah
    et al.
    Karolinska Inst, Inst Environm Med, S-17177 Stockholm, Sweden..
    Wei, Zheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Moelijker, Nynke
    Toxys, Leiden, Netherlands..
    Derr, Remco
    Toxys, Leiden, Netherlands..
    Persson, Kjell-Arne
    Swerim AB, Lulea, Sweden..
    Hendriks, Giel
    Toxys, Leiden, Netherlands..
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Yolanda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Karlsson, Hanna L.
    Karolinska Inst, Inst Environm Med, S-17177 Stockholm, Sweden..
    High variability in toxicity of welding fume nanoparticles from stainless steel in lung cells and reporter cell lines: the role of particle reactivity and solubility2019Inngår i: Nanotoxicology, ISSN 1743-5390, E-ISSN 1743-5404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Millions of people in the world perform welding as their primary occupation resulting in exposure to metal-containing nanoparticles in the fumes generated. Even though health effects including airway diseases are well-known, there is currently a lack of studies investigating how different welding set-ups and conditions affect the toxicity of generated nanoparticles of the welding fume. The aim of this study was to investigate the toxicity of nine types of welding fume particles generated via active gas shielded metal arc welding (GMAW) of chromium-containing stainless steel under different conditions and, furthermore, to correlate the toxicity to the particle characteristics. Toxicological endpoints investigated were generation of reactive oxygen species (ROS), cytotoxicity, genotoxicity and activation of ToxTracker reporter cell lines. The results clearly underline that the choice of filler material has a large influence on the toxic potential. Fume particles generated by welding with the tested flux-cored wire (FCW) were found to be more cytotoxic compared to particles generated by welding with solid wire or metal-cored wire (MCW). FCW fume particles were also the most potent in causing ROS and DNA damage and they furthermore activated reporters related to DNA double- strand breaks and p53 signaling. Interestingly, the FCW fume particles were the most soluble in PBS, releasing more chromium in the hexavalent form and manganese compared to the other fumes. These results emphasize the importance of solubility of different metal constituents of the fume particles, rather than the total metal content, for their acute toxic potential.

  • 99.
    McCracken, Joselle M.
    et al.
    Univ Illinois, Dept Chem, 600 S Matthews Ave, Urbana, IL 61801 USA..
    Rauzan, Brittany M.
    Univ Illinois, Dept Chem, 600 S Matthews Ave, Urbana, IL 61801 USA..
    Kjellman, Jacob C. E.
    Univ Illinois, Dept Chem, 600 S Matthews Ave, Urbana, IL 61801 USA..
    Su, Hanxiao
    Univ Illinois, Frederick Seitz Mat Res Lab, 1304 West Green St, Urbana, IL 61801 USA.;Univ Illinois, Dept Mat Sci & Engn, 1304 West Green St, Urbana, IL 61801 USA..
    Rogers, Simon A.
    Univ Illinois, Dept Chem & Biomol Engn, 600 S Matthews Ave, Urbana, IL 61801 USA..
    Nuzzo, Ralph G.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Univ Illinois, Dept Chem, 600 S Matthews Ave, Urbana, IL 61801 USA.;Univ Illinois, Frederick Seitz Mat Res Lab, 1304 West Green St, Urbana, IL 61801 USA.;Univ Illinois, Dept Mat Sci & Engn, 1304 West Green St, Urbana, IL 61801 USA.;KTH Royal Inst Technol, Surface & Corros Sci, Sch Engn Sci Chem Biotechnol & Hlth, Drottning Kristinasvag 51, S-10044 Stockholm, Sweden..
    Ionic Hydrogels with Biomimetic 4D-Printed Mechanical Gradients: Models for Soft-Bodied Aquatic Organisms2019Inngår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, nr 28, artikkel-id 1806723Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Direct-ink writing (DIW), a rapidly growing and advancing form of additive manufacturing, provides capacities for on-demand tailoring of materials to meet specific requirements for final designs. The penultimate challenge faced with the increasing demand of customization is to extend beyond modification of shape to create 4D structures, dynamic 3D structures that can respond to stimuli in the local environment. Patterning material gradients is foundational for assembly of 4D structures, however, there remains a general need for useful materials chemistries to generate gray scale gradients via DIW. Here, presented is a simple materials assembly paradigm using DIW to pattern ionotropic gradients in hydrogels. Using structures that architecturally mimic sea-jelly organisms, the capabilities of spatial patterning are highlighted as exemplified by selectively programming the valency of the ion-binding agents. Spatial gradients, when combined with geometry, allow for programming the flexibility and movement of iron oxide nanoparticle-loaded ionotropic hydrogels to generate 4D-printed structures that actuate in the presence of local magnetic fields. This work highlights approaches to 4D design complexity that exploits 3D-printed gray-scale/gradient mechanics.

  • 100.
    Mei, Nanxuan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Jonas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Blomberg, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Division Bioscience and Materials, RISE Research Institutes of Sweden, Stockholm, 111 21, Sweden.
    Influence of Biocorona Formation on the Transformation and Dissolution of Cobalt Nanoparticles under Physiological Conditions2019Inngår i: ACS Omega, ISSN 2470-1343, Vol. 4, nr 26, s. 21778-21791Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cobalt (Co) nanoparticles (NPs) are produced in different applications and unintentionally generated at several occupational and traffic settings. Their diffuse dispersion may lead to interactions with humans and aquatic organisms via different exposure routes that include their transformation/dissolution in biological media. This paper has investigated the particle stability and reactivity of Co NPs (dispersed by sonication prior to exposure) interacting with selected individual biomolecules (amino acids, polypeptides, and proteins) in phosphate-buffered saline (PBS). No or minor adsorption of amino acids (glutamine, glutamic acid, lysine, and cysteine) was observed on the Co NPs, independent of the functional group and charge. Instead, phosphate adsorption resulted in the formation of a surface layer (a corona) of Co phosphate. The adsorption of larger biomolecules (polyglutamic acid, polylysine, lysozyme, and mucin) was evident in parallel with the formation of Co phosphate. The dissolution of the Co NPs was rapid as 35-55% of the particle mass was dissolved within the first hour of exposure. The larger biomolecules suppressed the dissolution initially compared to exposure in PBS only, whereas the dissolution was essentially unaffected by the presence of amino acids, with cysteine as an exception. The formation of Co phosphate on the NP surface reduced the protective properties of the surface oxide of the Co NPs, as seen from the increased levels of the released Co when compared with the nonphosphate-containing saline. The results underline the diversity of possible outcomes with respect to surface characteristics and dissolution of Co NPs in biological media and emphasize the importance of surface interactions with phosphate on the NP characteristics and reactivity.

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