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Publications (10 of 24) Show all publications
Eriksson, M., Claesson, P. M., Järn, M., Wallqvist, V., Tuominen, M., Kappl, M., . . . Swerin, A. (2024). Effects of Gas Layer Thickness on Capillary Interactions at Superhydrophobic Surfaces. Langmuir, 40(9), 4801-4810
Open this publication in new window or tab >>Effects of Gas Layer Thickness on Capillary Interactions at Superhydrophobic Surfaces
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2024 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 40, no 9, p. 4801-4810Article in journal (Refereed) Published
Abstract [en]

Strongly attractive forces act between superhydrophobic surfaces across water due to the formation of a bridging gas capillary. Upon separation, the attraction can range up to tens of micrometers as the gas capillary grows, while gas molecules accumulate in the capillary. We argue that most of these molecules come from the pre-existing gaseous layer found at and within the superhydrophobic coating. In this study, we investigate how the capillary size and the resulting capillary forces are affected by the thickness of the gaseous layer. To this end, we prepared superhydrophobic coatings with different thicknesses by utilizing different numbers of coating cycles of a liquid flame spraying technique. Laser scanning confocal microscopy confirmed an increase in gas layer thickness with an increasing number of coating cycles. Force measurements between such coatings and a hydrophobic colloidal probe revealed attractive forces caused by bridging gas capillaries, and both the capillary size and the range of attraction increased with increasing thickness of the pre-existing gas layer. Hence, our data suggest that the amount of available gas at and in the superhydrophobic coating determines the force range and capillary growth. © 2024 The Authors.

Place, publisher, year, edition, pages
American Chemical Society, 2024
Keywords
Coatings; Flame spraying; Hydrophobicity; Molecules; Sols; Surface properties; water; Attractive force; Capillary force; Capillary interactions; Coating cycles; Different thickness; Gas layers; Gas molecules; Layer thickness; Super-hydrophobic surfaces; Superhydrophobic coatings; adult; article; capillary; confocal laser scanning microscopy; flame; gas; liquid; middle aged; thickness; Gases
National Category
Chemical Sciences
Identifiers
urn:nbn:se:ri:diva-72784 (URN)10.1021/acs.langmuir.3c03709 (DOI)2-s2.0-85186451464 (Scopus ID)
Note

Paxton Juuti and Janne Haapanen (Tampere University, Tampere, Finland) are acknowledged for preparing the LFS coatings and Oskar Karlsson (Swerim, Stockholm, Sweden) for cross-sectional SEM imaging. M.E. thanks SSF, the Swedish Foundation for Strategic Research (grant no. FID15-0029) and Omya International AG for funding. H.T. acknowledges the Alexander von Humboldt Foundation for financial support. D.V. would like to acknowledge financial support via the Priority Programme 2171. A.S. is a researcher in Pro2BE at Karlstad University, a research environment for processes and products for a circular forest-based bioeconomy. 

Available from: 2024-05-16 Created: 2024-05-16 Last updated: 2024-05-16Bibliographically approved
Zäll, E., Järn, M., Karlsson, S., Tryggeson, H., Tuominen, M., Sundin, M. & Wågberg, T. (2023). Aerosol-based deposition of broadband antireflective silica coating with closed mesoporous structure. Solar Energy Materials and Solar Cells, 250, 112078-112078, Article ID 112078.
Open this publication in new window or tab >>Aerosol-based deposition of broadband antireflective silica coating with closed mesoporous structure
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2023 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 250, p. 112078-112078, article id 112078Article in journal (Refereed) Published
Abstract [en]

Solar energy will be a crucial part of the sustainable, fossil free energy production of the future. A majority of this will be produced by solar collectors and photovoltaics. Important for the efficient utilization of the incident solar energy for both technologies are a cover glass with antireflective coatings giving it a high solar transmittance. In the current paper we describe the development of antireflective mesoporous silica coatings on low-iron float glass using the aerosol-based nFOG™ deposition technique. The coatings exhibit a hexagonal and closed pore structure, high smoothness, superhydrophilic properties (contact angle <5°) and consistent thicknesses of approximately 110 nm. This is in line with optimal thickness determined from simulations of the antireflective behavior. Low-iron float glass coated on both sides show a highly reproducible solar weighted transmittance of 95% in the wavelength range 300–2500 nm and an antireflective effect increasing with incident angle. The smoothness, closed pores and low contact angle indicate a high cleanability, which in combination with the high transmittance render a competitive broadband antireflective coating well adapted for solar glass applications.

Keywords
Antireflective coating, Aerosol-based deposition, nFOG™, Hexagonal mesoporous silica, Solar collector, Solar glass
National Category
Materials Engineering Manufacturing, Surface and Joining Technology Materials Chemistry Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:ri:diva-61135 (URN)10.1016/j.solmat.2022.112078 (DOI)
Projects
Development of Functional Coatings on Cover Glass for Produktion of more Efficient Solar CollectorsTransparent multifunctional thin films on low–iron float glass for solar energy applications
Funder
Vinnova, 2018-02588Swedish Energy Agency, 52487-1Swedish Energy Agency, 45419-1Swedish Research Council, 2017–59504862
Note

Funding: Vinnova 2018-02588. Energimyndigheten 45419-1. Vetenskapsrådet 2017-59504862

Available from: 2022-11-08 Created: 2022-11-08 Last updated: 2024-03-25Bibliographically approved
Zäll, E., Järn, M., Karlsson, S., Tryggeson, H., Tuominen, M., Sundin, M. & Wågberg, T. (2023). Aerosol-based deposition of broadband antireflective silica coating withclosed mesoporous structure. Solar Energy Materials and Solar Cells, 250, 112078, Article ID 112078.
Open this publication in new window or tab >>Aerosol-based deposition of broadband antireflective silica coating withclosed mesoporous structure
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2023 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 250, p. 112078-, article id 112078Article in journal (Refereed) Published
Abstract [en]

Solar energy will be a crucial part of the sustainable, fossil free energy production of the future. Amajority of this will be produced by solar collectors and photovoltaics. Important for the efficientutilization of the incident solar energy for both technologies are a cover glass with antireflectivecoatings giving it a high solar transmittance. In the current paper we describe the development ofantireflective mesoporous silica coatings on low-iron float glass using the aerosol-based nFOGTMdeposition technique. The coatings exhibit a hexagonal and closed pore structure, a high smoothness,and consistent thicknesses of approximately 110 nm. This is in line with optimal thicknessesdetermined from simulations of the antireflective behavior. Low-iron float glass coated on both sidesshow a highly reproducible solar weighted transmittance of 95 % in the wavelength range 300-2500nm and an antireflective effect increasing with incident angle. The smoothness and closed poresassociated with high cleanability, as well as high transmittance makes it a competitive broadbandantireflective coating well adapted for solar glass applications.

Keywords
Antireflective coating, aerosol-based deposition, nFOG, hexagonal mesoporous silica, solar collector, solar glass
National Category
Physical Chemistry Materials Chemistry Inorganic Chemistry
Identifiers
urn:nbn:se:ri:diva-60001 (URN)10.2139/ssrn.4130248 (DOI)2-s2.0-85141234079 (Scopus ID)
Projects
Development of Functional Coatings on Cover Glass for Produktion of more Efficient Solar Collectors
Funder
Vinnova, 2018-02588
Note

Funding: Vinnova 2018-02588

Available from: 2022-08-29 Created: 2022-08-29 Last updated: 2024-05-23Bibliographically approved
Karlsson, S., Järn, M. & Zäll, E. (2023). Antireflektiv beläggning i världsklass ger effektivare solfångare. GLAS (4), 36-37
Open this publication in new window or tab >>Antireflektiv beläggning i världsklass ger effektivare solfångare
2023 (Swedish)In: GLAS, no 4, p. 36-37Article in journal (Other (popular science, discussion, etc.)) Published
Abstract [sv]

I ett nyligen avslutat forskningsprojekt har Absolicon Solar Collector tillsammans med RISE Research Institutes of Sweden och Umeå universitet utvecklat en ny toppmodern antireflektiv beläggning som kan göra Absolicons solfångare än mer effektiva. Nu siktar man på ett nytt projekt för att skala upp metoden.

National Category
Nano Technology Inorganic Chemistry Condensed Matter Physics Atom and Molecular Physics and Optics Materials Engineering
Identifiers
urn:nbn:se:ri:diva-68087 (URN)
Projects
Utveckling av Funktionella Ytbeläggningar på Täckglaset för Produktion av Effektivare Solfångare
Funder
Vinnova, 2018-02588Swedish Energy Agency, 52487-1
Available from: 2023-11-23 Created: 2023-11-23 Last updated: 2023-11-24Bibliographically approved
Wojas, N., Tyrode, E., Corkery, R., Ernstsson, M., Wallqvist, V., Järn, M., . . . Claesson, P. M. (2023). Calcite Surfaces Modified with Carboxylic Acids (C2 to C18): Layer Organization, Wettability, Stability, and Molecular Structural Properties. Langmuir, 39(42), 14840-14852
Open this publication in new window or tab >>Calcite Surfaces Modified with Carboxylic Acids (C2 to C18): Layer Organization, Wettability, Stability, and Molecular Structural Properties
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2023 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 39, no 42, p. 14840-14852Article in journal (Refereed) Published
Abstract [en]

A fundamental understanding of the interactions between mineral surfaces and amphiphilic surface modification agents is needed for better control over the production and uses of mineral fillers. Here, we controlled the carboxylic acid layer formation conditions on calcite surfaces with high precision via vapor deposition. The properties of the resulting carboxylic acid layers were analyzed using surface-sensitive techniques, such as atomic force microscopy (AFM), contact angle measurements, angle resolved X-ray photoelectron spectroscopy (XPS), and vibrational sum-frequency spectroscopy. A low wettability was achieved with long hydrocarbon chain carboxylic acids such as stearic acid. The stearic acid layer formed by vapor deposition is initially patchy, but with increasing vapor exposure time, the patches grow and condense into a homogeneous layer with a thickness close to that expected for a monolayer as evaluated by AFM and XPS. The build-up process of the layer occurs more rapidly at higher temperatures due to the higher vapor pressure. The stability of the deposited fatty acid layer in the presence of a water droplet increases with the chain length and packing density in the adsorbed layer. Vibrational sum frequency spectroscopy data demonstrate that the stearic acid monolayers on calcite have their alkyl chains in an all-trans conformation and are anisotropically distributed on the plane of the surface, forming epitaxial monolayers. Vibrational spectra also show that the stearic acid molecules interact with the calcite surface through the carboxylic acid headgroup in both its protonated and deprotonated forms. The results presented provide new molecular insights into the properties of adsorbed carboxylic acid layers on calcite.

National Category
Mechanical Engineering
Identifiers
urn:nbn:se:ri:diva-67911 (URN)10.1021/acs.langmuir.3c01252 (DOI)2-s2.0-85175357225 (Scopus ID)
Note

This work was funded by Omya International AG. ET acknowledges support from the Swedish Research Council (VR).

Available from: 2023-11-27 Created: 2023-11-27 Last updated: 2024-02-28Bibliographically approved
Zäll, E., Karlsson, S., Järn, M., Segervald, J., Lundberg, P. & Wågberg, T. (2023). Durability of antireflective SiO2 coatings with closed pore structure. Solar Energy Materials and Solar Cells, 261, Article ID 112521.
Open this publication in new window or tab >>Durability of antireflective SiO2 coatings with closed pore structure
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2023 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 261, article id 112521Article in journal (Refereed) Published
Abstract [en]

The use of antireflective coatings to increase the transmittance of the cover glass is a central aspect of achieving high efficiencies for solar collectors and photovoltaics alike. Considering an expected lifetime of 20–30 years for solar energy installations, the durability of the antireflective surfaces is essential. Here, a novel antireflective SiO2 coating with a hexagonally ordered closed pore structure, produced with an aerosol-based sol-gel method is benchmarked against two commercial coatings; produced with acid etching and sol-gel roll coating. The optical and mechanical properties together with contact angle characteristics were evaluated before and after various durability tests, including climate chamber tests, outdoor exposure, and abrasion. Compared to the commercial antireflective coatings with open pore structures, the novel coating performed in parity, or better, in all tests. Based on the results of humidity freeze and industrial climate chamber tests, it appears that the coating with closed pore structure has a better ability to prevent water adsorption. Additionally, the closed pore structure of the coating seems to minimize the accumulation of dirt and deposits. The abrasion and cleanability test further confirm the advantages of a closed pore structure, showcasing the coating's mechanical durability. While the coatings exhibit similar hardness and reduced elastic modulus, the closed pore coating proves to be even harder after undergoing the industrial climate chamber test, but also slightly more brittle, as indicated by the probability of crack initiation. In summary the closed pore structure is well suited for tempered and arid climates, making it a truly competitive alternative to existing antireflective coatings.

Keywords
Antireflective coating, Aerosol-based deposition, Accelerated ageing, Durability, Solar collector, Solar glass
National Category
Atom and Molecular Physics and Optics Inorganic Chemistry Materials Engineering Materials Chemistry
Identifiers
urn:nbn:se:ri:diva-66104 (URN)10.1016/j.solmat.2023.112521 (DOI)
Projects
Development of Functional Coatings on Cover Glass for Produktion of more Efficient Solar CollectorsTransparent multifunctional thin films on low–iron float glass for solar energy applications
Funder
Vinnova, 2018-02588Swedish Research Council, 2017-59504862Swedish Research Council, 2021–04629Swedish Energy Agency, 45419-1Swedish Energy Agency, 52487-1
Note

This work was supported by funding from Vinnova, the Swedish Innovation Agency's Material-based Competitiveness program [Grant No. 2018-02588]; Vetenskapsradet (Grant No. 2017-59504862, 2021–04629); Swedish Energy Agency (Grant No. 45419-1 and 52487-1); the Industrial doctoral school at UmU and Absolicon.

Available from: 2023-08-25 Created: 2023-08-25 Last updated: 2023-08-28Bibliographically approved
Eriksson, M., Claesson, P. M., Järn, M., Wallqvist, V., Tuominen, M., Kappl, M., . . . Swerin, A. (2023). Effects of liquid surface tension on gas capillaries and capillary forces at superamphiphobic surfaces. Scientific Reports, 13(1), Article ID 6794.
Open this publication in new window or tab >>Effects of liquid surface tension on gas capillaries and capillary forces at superamphiphobic surfaces
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2023 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 13, no 1, article id 6794Article in journal (Refereed) Published
Abstract [en]

The formation of a bridging gas capillary between superhydrophobic surfaces in water gives rise to strongly attractive interactions ranging up to several micrometers on separation. However, most liquids used in materials research are oil-based or contain surfactants. Superamphiphobic surfaces repel both water and low-surface-tension liquids. To control the interactions between a superamphiphobic surface and a particle, it needs to be resolved whether and how gas capillaries form in non-polar and low-surface-tension liquids. Such insight will aid advanced functional materials development. Here, we combine laser scanning confocal imaging and colloidal probe atomic force microscopy to elucidate the interaction between a superamphiphobic surface and a hydrophobic microparticle in three liquids with different surface tensions: water (73 mN m−1), ethylene glycol (48 mN m−1) and hexadecane (27 mN m−1). We show that bridging gas capillaries are formed in all three liquids. Force-distance curves between the superamphiphobic surface and the particle reveal strong attractive interactions, where the range and magnitude decrease with liquid surface tension. Comparison of free energy calculations based on the capillary menisci shapes and the force measurements suggest that under our dynamic measurements the gas pressure in the capillary is slightly below ambient. © 2023, The Author(s).

Place, publisher, year, edition, pages
Nature Research, 2023
National Category
Physical Chemistry
Identifiers
urn:nbn:se:ri:diva-64423 (URN)10.1038/s41598-023-33875-9 (DOI)2-s2.0-85153917455 (Scopus ID)
Note

M.E. thanks SSF, the Swedish Foundation for Strategic Research (Grant No. FID15-0029) and Omya International AG for funding. H.T. acknowledges the Alexander von Humboldt Foundation for financial support. D.V. likes to acknowledge financial support via the Priority Programme 2171. A.S. is researcher at Pro2BE at Karlstad University, a research environment for Processes and products for a circular forest-based bioeconomy. M.E. thanks SSF, the Swedish Foundation for Strategic Research (Grant No. FID15-0029) and Omya International AG for funding. H.T. acknowledges the Alexander von Humboldt Foundation for financial support. D.V. likes to acknowledge financial support via the Priority Programme 2171. A.S. is researcher at Pro2BE at Karlstad University, a research environment for Processes and products for a circular forest-based bioeconomy.

Available from: 2023-05-12 Created: 2023-05-12 Last updated: 2023-12-20Bibliographically approved
Karlsson, S., Järn, M. & Lindh, E. M. (2023). Nya ytbeläggningar ska minska snöförluster på solcellsanläggningar. GLAS (1), 34-37
Open this publication in new window or tab >>Nya ytbeläggningar ska minska snöförluster på solcellsanläggningar
2023 (Swedish)In: GLAS, no 1, p. 34-37Article in journal (Other (popular science, discussion, etc.)) Published
Abstract [sv]

För att slippa vänta på plusgrader håller en samling forskare på RISE på attutveckla och testa nya ytbeläggningar för solceller som ska göra att snö och isinte fäster på dem. Snö och is kan leda till stopp i elproduktionen - en solcellsmodulsom är täckt av snö och is generar i praktiken ingen elektricitet eftersomsolljuset inte tränger igenom i tillräcklig omfattning. Dessutom kan rejälasnömängder leda till stora belastningar på underliggande konstruktioner.

Place, publisher, year, edition, pages
Glasbranschföreningen, 2023
Keywords
snöavvisande, isavvisande, solceller, antireflektiva beläggningar, tunnfilmsbeläggning
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-64215 (URN)
Projects
Utveckling och testning av snö- och isavvisande ytbeläggningar för solceller
Funder
Swedish Energy Agency, 52472-1
Available from: 2023-03-09 Created: 2023-03-09 Last updated: 2023-05-25Bibliographically approved
Zäll, E., Nordenström, A., Järn, M., Mossegård, J. & Wågberg, T. (2022). Environmentally sustainable electroplating of selective cobalt-chromium coating on stainless steel for efficient solar collectors. Solar Energy Materials and Solar Cells, 245, Article ID 111821.
Open this publication in new window or tab >>Environmentally sustainable electroplating of selective cobalt-chromium coating on stainless steel for efficient solar collectors
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2022 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 245, article id 111821Article in journal (Refereed) Published
Abstract [en]

Half of today's global energy consumption is in the form of heating and cooling. Solar collectors are the most promising sustainable alternative to fossil fuels in this sector. The most important component in a solar collector is the receiver, which by use of a selective surface absorbs and converts solar irradiance to thermal energy. Herein, a novel selective surface for low-to mid-temperature solar collectors is developed, studied and presented. The surface is produced by electroplating a cobalt-chromium coating on a stainless steel substrate using an electrolyte based on a deep eutectic solvent. Our method makes use of trivalent instead of traditionally used hexavalent chromium, which significantly reduces health-related issues and makes it more environmentally benign. We obtain a coating of chromium doped cobalt where the surface exhibits an absorptance and emittance of 0.96 and 0.14, respectively, giving it a solar-to-thermal efficiency of 0.95. An observed loss in optical efficiency, is shown to correlate to an oxidation of the metallic cobalt to Co3O4 at elevated temperatures. We further show that this oxidation can be mitigated by dip-coating a protective silica top coating, which concurrently improves the optical selectivity of the surface. The present selective surface is efficient, cheap, scalable, and easy to produce sustainably, making it competitive to industry standards. We foresee that our method will have impact on the advancement of improved low-to mid-temperature solar collectors, assisting a faster transition towards a sustainable society.

Place, publisher, year, edition, pages
Elsevier B.V., 2022
Keywords
Cobalt-chromium coating, Deep eutectic solvent, Electroplating, Selective surface, Solar absorber, Trivalent chromium
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-59784 (URN)10.1016/j.solmat.2022.111821 (DOI)2-s2.0-85132515771 (Scopus ID)
Available from: 2022-07-04 Created: 2022-07-04 Last updated: 2023-05-25Bibliographically approved
Wojas, N., Dobryden, I., Wallqvist, V., Swerin, A., Järn, M., Schoelkopf, J., . . . Claesson, P. M. (2021). Nanoscale Wear and Mechanical Properties of Calcite: Effects of Stearic Acid Modification and Water Vapor. Langmuir, 37(32), 9826-9837
Open this publication in new window or tab >>Nanoscale Wear and Mechanical Properties of Calcite: Effects of Stearic Acid Modification and Water Vapor
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2021 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 37, no 32, p. 9826-9837Article in journal (Refereed) Published
Abstract [en]

Understanding the wear of mineral fillers is crucial for controlling industrial processes, and in the present work, we examine the wear resistance and nanomech. properties of bare calcite and stearic acid-modified calcite surfaces under dry and humid conditions at the nanoscale. Measurements under different loads allow us to probe the situation in the absence and presence of abrasive wear. The sliding motion is in general characterized by irregular stick-slip events that at higher loads lead to abrasion of the brittle calcite surface. Bare calcite is hydrophilic, and under humid conditions, a thin water layer is present on the surface. This water layer does not affect the friction force. However, it slightly decreases the wear depth and strongly influences the distribution of wear particles. In contrast, stearic acid-modified surfaces are hydrophobic. Nevertheless, humidity affects the wear characteristics by decreasing the binding strength of stearic acid at higher humidity. A complete monolayer coverage of calcite by stearic acid results in a significant reduction in wear but only a moderate reduction in friction forces at low humidity and no reduction at 75% relative humidity (RH). Thus, our data suggest that the wear reduction does not result from a lowering of the friction force but rather from an increased ductility of the surface region as offered by the stearic acid layer. An incomplete monolayer of stearic acid on the calcite surface provides no reduction in wear regardless of the RH investigated. Clearly, the wear properties of modified calcite surfaces depend crucially on the packing d. of the surface modifier and also on the air humidity.

Place, publisher, year, edition, pages
American Chemical Society, 2021
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:ri:diva-56145 (URN)10.1021/acs.langmuir.1c01390 (DOI)
Available from: 2021-09-01 Created: 2021-09-01 Last updated: 2023-06-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4746-6559

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