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Publications (10 of 25) Show all publications
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
Ernstsson, M., Dedinaite, A., Rojas, O. J. & Claesson, P. M. (2023). Two different approaches to XPS quantitative analysis of polyelectrolyte adsorption layers. Surface and Interface Analysis, 55(1), 26-40
Open this publication in new window or tab >>Two different approaches to XPS quantitative analysis of polyelectrolyte adsorption layers
2023 (English)In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 55, no 1, p. 26-40Article in journal (Refereed) Published
Abstract [en]

X-ray photoelectron spectroscopy (XPS) was employed to quantify adsorption of polyelectrolytes from aqueous solutions of low ionic strength onto mica, glass, and silica. Silica surfaces were conditioned in base or in acid media as last pre-treatment step (silica-base last or silica-acid last, respectively). Consistency in the determined adsorbed amount, Γ, was obtained independent of the choice of XPS mode and with the two quantification approaches used in the data evaluation. Under the same adsorption conditions, the adsorbed amount, Γ, varied as Γmica > Γsilica-base last ≈ Γglass > Γsilica-acid last. In addition, the adsorbed amount increased with decreasing polyelectrolyte charge density (100% to 1% of segments being charged) for all substrates. Large adsorbed amount was measured for low-charge density polyelectrolytes, but the number of charged segments per square nanometer was low due to steric repulsion between polyelectrolyte chains that limited the adsorption. The adsorbed amount of highly charged polyelectrolytes was controlled by electrostatic interactions and thus limited to that needed to neutralize the substrate surface charge density. For silica, the adsorbed amount depended on the cleaning method, suggesting that this process influenced surface concentration and fraction of different silanol groups. Our results demonstrate that for silica, a higher density and/or more acidic silanol groups are formed using base, rather than acid, treatment in the last step. © 2022 The Authors.

Place, publisher, year, edition, pages
John Wiley and Sons Ltd, 2023
Keywords
adsorption, ESCA, glass, mica, polyelectrolyte, quantification, silica, surface conditioning, XPS, Ionic strength, Polyelectrolytes, Substrates, X ray photoelectron spectroscopy, Adsorbed amount, Adsorption layer, Low ionic strength, Polyelectrolyte adsorption, Silanol groups, Silica surface, Surface and interface analysis
National Category
Physical Chemistry
Identifiers
urn:nbn:se:ri:diva-61228 (URN)10.1002/sia.7154 (DOI)2-s2.0-85141359214 (Scopus ID)
Available from: 2022-12-02 Created: 2022-12-02 Last updated: 2024-02-28Bibliographically approved
Ovaska, S.-S., Hiltunen, S., Ernstsson, M., Schuster, E., Altskär, A. & Backfolk, K. (2016). Characterization of rapeseed oil/coconut oil mixtures and their penetration into hydroxypropylated-starch-based barrier coatings containing an oleophilic mineral. Progress in organic coatings, 101, 569-576
Open this publication in new window or tab >>Characterization of rapeseed oil/coconut oil mixtures and their penetration into hydroxypropylated-starch-based barrier coatings containing an oleophilic mineral
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2016 (English)In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 101, p. 569-576Article in journal (Refereed) Published
Abstract [en]

A study was conducted that demonstrated that the blending of edible oils leads to changes in surface tension, thermal properties, viscosity, and oil penetration times through a barrier-coated paperboard. The results emphasize the significance of testing the oil and grease resistance (OGR) oil blends in order-to verify the suitability of the packaging material for real-life end-use applications. The results of the OGR determinations suggest that hydroxypropylated-starch-based composite coatings containing an oleophilic high aspect ratio mineral can be tailored for food shaving different fatty acid compositions by varying the pigmentation level. Compared to standard OGR tests, confocal laser scanning microscopy (CLSM)-based techniques make it possible to evaluate the oil penetration time and its diffusion behavior very accurately, both inside the coating layer and in the bulk matrix. It was found that, at room temperature, coconut oil tends to crystallize inside the substrate, inducing swelling of the coating layer, which probably has an influence on the physicomechanical properties of the packaging material.

National Category
Polymer Technologies Food Engineering Manufacturing, Surface and Joining Technology Physical Chemistry Other Chemistry Topics Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-27582 (URN)10.1016/j.porgcoat.2016.10.001 (DOI)2-s2.0-84991493060 (Scopus ID)
Available from: 2016-12-20 Created: 2016-12-19 Last updated: 2024-02-28Bibliographically approved
Javed, A., Ullsten, H., Ernstsson, M. & Järnström, L. (2016). Study of starch and starch-PVOH blends and effects of plasticizers on mechanical and barrier properties of coated paperboard. Nordic Pulp & Paper Research Journal, 31(3), 499-510
Open this publication in new window or tab >>Study of starch and starch-PVOH blends and effects of plasticizers on mechanical and barrier properties of coated paperboard
2016 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 499-510Article in journal (Refereed) Published
Abstract [en]

The mechanical properties of self-supporting films based on starch-plasticizer and starch-PVOH-plasticizer and the barrier properties of paperboard coated with solutions of these polymers have been studied. The plasticizers used were glycerol, polyethylene glycol and citric acid. It was shown that the addition of a plasticizer and PVOH to starch substantially increases the flexibility of starch films. It was seen that curing the self-supporting films led to a decrease in flexibility. After heat-treatment, a substantial increase in storage modulus was observed only in the starch-PVOH-citric-acid blend films. Tensile tests on the films indicate that citric acid did not cause any noticeable phase separation. Citric acid acted as a compatibilizer for starch-PVOH blends even though a similar enrichment of PVOH at the air-solid interface was observed with both citric acid and polyethylene glycol as plasticizer. The properties of barrier coatings greatly reflected the compatibility of starch-PVOH blends containing citric acid. The only plasticizer that resulted in a lower water vapour transmission rate through the starch and starch-PVOH coatings was citric acid, which suggests that cross-linking took place. With four layers, coatings based of starch-PVOH possessed the same oxygen- transmission rate with citric acid as without citric acid.

Place, publisher, year, edition, pages
Swedish Association of Pulp and Paper Engineers, 2016
Keywords
Barrier coating, Citric acid, Glycerol, Mechanical properties, Polyethylene glycol, Starch Pages
National Category
Polymer Technologies Polymer Chemistry
Identifiers
urn:nbn:se:ri:diva-27769 (URN)10.3183/NPPRJ-2016-31-03-p499-510 (DOI)
Available from: 2017-01-06 Created: 2017-01-06 Last updated: 2024-02-28Bibliographically approved
Brodin, I., Ernstsson, M., Gellerstedt, G. & Sjöholm, E. (2012). Oxidative stabilisation of kraft lignin for carbon fibre production (ed.). Holzforschung (2), 141-147
Open this publication in new window or tab >>Oxidative stabilisation of kraft lignin for carbon fibre production
2012 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, no 2, p. 141-147Article in journal (Refereed) Published
Abstract [en]

With the aim of investigating kraft lignin as a raw material for carbon fibre production, different lignins have been stabilised in air at conditions varied according to a full factorial experimental design. The lignins under examination were purified kraft lignin powders originating from birch, spruce/pine and Eucalyptus globules, as well as lignin fibres originating from birch with 5 poly(ethylene oxide) (PEO) added as a plasticiser. The influence of temperature, time and heating rate on yield and glass-transition temperature (Tg) was investigated. The highest yield was achieved after stabilisation at 280°C during 2h with a heating rate of 0.2°C min -1. The Tg of all lignin powders was increased when stabilisation occurred under harsher conditions. X-ray photoelectron spectroscopy analysis (XPS) of both the outer surface and the cleaved cross-section of individual lignin/PEO fibres showed a clear gradient in the degree of chemical modification, with the major change occurring on the surface resulting in the appearance of a skin-core structure after stabilisation. The behaviour of the lignin fibres during stabilisation is similar to that of pitch-based fibres, indicating good possibilities for lignin as raw material for carbon fibre production.

National Category
Other Materials Engineering Organic Chemistry
Identifiers
urn:nbn:se:ri:diva-9755 (URN)10.1515/HF.2011.133 (DOI)2-s2.0-84860606788 (Scopus ID)
Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2024-02-28Bibliographically approved
Arnold, C., Klein, G., Maaloum, M., Ernstsson, M., Larsson, A. & Marie, P. (2011). Surfactant distribution in waterborne acrylic films. 2 Surface Investigation (ed.). Colloids and Surfaces A: Physicochemical and Engineering Aspects, 374(1-3), 58-68
Open this publication in new window or tab >>Surfactant distribution in waterborne acrylic films. 2 Surface Investigation
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2011 (English)In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 374, no 1-3, p. 58-68Article in journal (Refereed) Published
Abstract [en]

This paper presents results on sodium dodecyl sulfate (SDS) enrichment at the surface of pure acrylic or acrylic/laponite composite latex films. Surface concentrations were measured by Confocal Raman Spectroscopy leading to higher values than the nominal concentration of 6 wt%. X-ray Photoelectron Spectroscopy (XPS) analyses showed uppermost surface layers saturated with SDS in most cases. High resolution Atomic Force Microscopy (AFM) revealed a variety of morphologies for these surfactant top layers, highlighting the occurrence of SDS bilayers in different configurations. In an attempt to check for a correlation between the surface concentration of the surfactant in dry films and the concentration of free surfactant in water in the initial latex, this latter concentration was determined from the level of the plateau in adsorption isotherms. Adsorption studies by conductimetry showed an unexpected increase of the amount of adsorbed SDS with pH. The proposed interpretation is that, upon acrylic acid neutralization, the chains at the surface become more hydrophilic and spread out in water, revealing more sites for SDS to adsorb on. No correlation between free surfactant and surface enrichment could be established, indicating that the enrichment process is more complex than expected.

Keywords
Latex film, Surfactant distribution, Surface enrichment, SDS, Adsorption isotherm, Confocal Raman Spectroscopy, XPS, AFM Surfactant distribution in waterborne acrylic films Surface Investigation
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-26385 (URN)10.1016/j.colsurfa.2010.11.008 (DOI)
Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2024-02-28Bibliographically approved
Bryne, L. E., Lausmaa, J., Ernstsson, M., Englund, F. & Wålinder, M. (2010). Ageing of modified wood. Part 2: Determination of surface composition of acetylated, furfurylated, and thermally modified wood by XPS and ToF-SIMS (ed.). Holzforschung, 64(3), 305–313
Open this publication in new window or tab >>Ageing of modified wood. Part 2: Determination of surface composition of acetylated, furfurylated, and thermally modified wood by XPS and ToF-SIMS
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2010 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 64, no 3, p. 305–313-Article in journal (Refereed) Published
Abstract [en]

The main objective of this work was to study the chemical composition of surfaces and ageing effects on acetylated pine (Pinus sylvestris), heat treated spruce (Picea abies), and furfurylated radiata pine (Pinus radiata) in comparison to unmodified wood. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were the instruments of choice. Observation with a low-vacuum scanning electron microscope (LV-SEM) complemented the study. The spectroscopic information was also linked to a parallel wettability study on matched wood samples by the Wilhelmy method. The results show that XPS and ToF-SIMS are two powerful tools that in combination give complementary information, both quantitative and qualitative, and are well suited for observation of the ageing process of different wood surfaces. The hydrophobization process as a result of migration of extractives during ageing was well quantified by the XPS measurements and the results correlated well with wetting results. Several specific hydrophobic substances could be identified by ToF-SIMS measurements.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6172 (URN)11548 (Local ID)11548 (Archive number)11548 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2024-02-28Bibliographically approved
Englund, F., Bryne, L. E., Ernstsson, M., Lausmaa, J. & Wålinder, M. (2009). Some aspects on the determination of surface chemical composition and wettability of modified wood (ed.). In: Proceedings of The Fourth European Conference on Wood Modification.: . Paper presented at The Fourth European Conference on Wood Modification. Norra Latin City Conference Centre, Stockholm, Sweden. 27-29th April 2009.. SP Technical Research Institute of Sweden
Open this publication in new window or tab >>Some aspects on the determination of surface chemical composition and wettability of modified wood
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2009 (English)In: Proceedings of The Fourth European Conference on Wood Modification., SP Technical Research Institute of Sweden , 2009, , p. 553-560Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
SP Technical Research Institute of Sweden, 2009. p. 553-560
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-11853 (URN)10285 (Local ID)10285 (Archive number)10285 (OAI)
Conference
The Fourth European Conference on Wood Modification. Norra Latin City Conference Centre, Stockholm, Sweden. 27-29th April 2009.
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2024-02-28Bibliographically approved
Englund, F., Bryne, L. E., Ernstsson, M., Lausmaa, J. & Wålinder, M. (2009). Some aspects on the determination of surface chemical composition and wettability of modified wood (ed.). Wood Material Science & Engineering, 4(1-2), 80-85
Open this publication in new window or tab >>Some aspects on the determination of surface chemical composition and wettability of modified wood
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2009 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, no 1-2, p. 80-85Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6151 (URN)14783 (Local ID)14783 (Archive number)14783 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2024-02-28Bibliographically approved
Englund, F., Bryne, L. E., Ernstsson, M., Lausmaa, J. & Wålinder, M. (2009). Spectroscopic studies of surface chemical composition and wettability of modified wood (ed.). Wood Material Science & Engineering, 4(1-2), 80–85
Open this publication in new window or tab >>Spectroscopic studies of surface chemical composition and wettability of modified wood
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2009 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, no 1-2, p. 80–85-Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6135 (URN)10322 (Local ID)10322 (Archive number)10322 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2024-02-28Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3695-1150

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