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Skedung, L., Savvidou, E., Schellenberger, S., Reimann, A., Cousins, I. T. & Benskin, J. P. (2024). Identification and quantification of fluorinated polymers in consumer products by combustion ion chromatography and pyrolysis-gas chromatography-mass spectrometry. Environmental Science: Processes & Impacts
Open this publication in new window or tab >>Identification and quantification of fluorinated polymers in consumer products by combustion ion chromatography and pyrolysis-gas chromatography-mass spectrometry
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2024 (English)In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895Article in journal (Refereed) Epub ahead of print
Abstract [en]

Total fluorine was determined in 45 consumer product samples from the Swedish market which were either suspected or known to contain fluorinated polymers. Product categories included cookware (70–550 000 ppm F), textiles (10–1600 ppm F), electronics (20–2100 ppm F), and personal care products (10–630 000 ppm F). To confirm that the fluorine was organic in nature, and deduce structure, a qualitative pyrolysis-gas chromatography-mass spectrometry (pyr-GC/MS) method was validated using a suite of reference materials. When applied to samples with unknown PFAS content, the method was successful at identifying polytetrafluoroethylene (PTFE) in cookware, dental products, and electronics at concentrations as low as 0.1–0.2 wt%. It was also possible to distinguish between 3 different side-chain fluorinated polymers in textiles. Several products appeared to contain high levels of inorganic fluorine. This is one of the few studies to quantify fluorine in a wide range of consumer plastics and provides important data on the concentration of fluorine in materials which may be intended for recycling, along with insights into the application of pyr-GC/MS for structural elucidation of fluorinated polymers in consumer products.

National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-68677 (URN)10.1039/d3em00438d (DOI)
Funder
Vinnova, 2021-04200Swedish Research Council Formas, 2020-01978
Note

Funding Vinnova 2021-04200 and Formas 2020-01978

Available from: 2023-12-27 Created: 2023-12-27 Last updated: 2023-12-27
Sjövall, P., Gregoire, S., Wargniez, W., Skedung, L. & Luengo, G. (2022). 3D Molecular Imaging of Stratum Corneum by Mass Spectrometry Suggests Distinct Distribution of Cholesteryl Esters Compared to Other Skin Lipids. International Journal of Molecular Sciences, 23(22), Article ID 13799.
Open this publication in new window or tab >>3D Molecular Imaging of Stratum Corneum by Mass Spectrometry Suggests Distinct Distribution of Cholesteryl Esters Compared to Other Skin Lipids
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2022 (English)In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 23, no 22, article id 13799Article in journal (Refereed) Published
Abstract [en]

The crucial barrier properties of the stratum corneum (SC) depend critically on the design and integrity of its layered molecular structure. However, analysis methods capable of spatially resolved molecular characterization of the SC are scarce and fraught with severe limitations, e.g., regarding molecular specificity or spatial resolution. Here, we used 3D time-of-flight secondary ion mass spectrometry to characterize the spatial distribution of skin lipids in corneocyte multilayer squams obtained by tape stripping. Depth profiles of specific skin lipids display an oscillatory behavior that is consistent with successive monitoring of individual lipid and corneocyte layers of the SC structure. Whereas the most common skin lipids, i.e., ceramides, C24:0 and C26:0 fatty acids and cholesteryl sulfate, are similarly organized, a distinct 3D distribution was observed for cholesteryl oleate, suggesting a different localization of cholesteryl esters compared to the lipid matrix separating the corneocyte layers. The possibility to monitor the composition and spatial distribution of endogenous lipids as well as active drug and cosmetic substances in individual lipid and corneocyte layers has the potential to provide important contributions to the basic understanding of barrier function and penetration in the SC. © 2022 by the authors.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
3D ToF-SIMS, cholesteryl esters, layer structure, lipid distribution, stratum corneum
National Category
Physical Chemistry
Identifiers
urn:nbn:se:ri:diva-61377 (URN)10.3390/ijms232213799 (DOI)2-s2.0-85142634501 (Scopus ID)
Note

Funding details: Vetenskapsrådet, VR, 2019-03731; Funding text 1: Financial support for this work was provided by the Swedish Research Council, grant No. 2019-03731 (P.S.).

Available from: 2022-12-08 Created: 2022-12-08 Last updated: 2023-06-05Bibliographically approved
Svedlund, J. & Skedung, L. (2022). PFAS Substitution Guide : FOR TEXTILE SUPPLY CHAINS.
Open this publication in new window or tab >>PFAS Substitution Guide : FOR TEXTILE SUPPLY CHAINS
2022 (English)Report (Other academic)
Abstract [en]

This guide is a support for textile industry players, to improve commmunication about chemicals and raise the possibility for well-informed substitution work. It focuses on subsitution of highly fluorinated substances, also known as per- and polyfluoroalkyl substances (PFAS), offering textile buyers a deeper understanding about water repellence and the associated chemistry. The guide can be used as a starting point for your chemicals management and substitution work, with many links to other information sources. We recommend using the Table of Contents below as a navigational tool, to start filling any knowledge gaps and expand your reading from there.

Publisher
p. 27
Series
RISE Rapport ; 2022:98
National Category
Environmental Sciences
Identifiers
urn:nbn:se:ri:diva-60078 (URN)978-91-89711-41-9 (ISBN)
Available from: 2022-09-02 Created: 2022-09-02 Last updated: 2023-05-25Bibliographically approved
Ali, A., Skedung, L., Burleigh, S., Lavant, E., Ringstad, L., Anderson, C., . . . Engblom, J. (2022). Relationship between sensorial and physical characteristics of topical creams: A comparative study on effects of excipients. International Journal of Pharmaceutics, 613, Article ID 121370.
Open this publication in new window or tab >>Relationship between sensorial and physical characteristics of topical creams: A comparative study on effects of excipients
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2022 (English)In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 613, article id 121370Article in journal (Refereed) Published
Abstract [en]

Rising consumer demands for safer, more natural, and sustainable topical products have led to increased interest in finding alternative excipients, while retaining functionality and cosmetic appeal. Particle-stabilized Pickering creams have emerged as possible alternatives to replace traditional surfactant-stabilized creams and are thus one of the focuses in this study. The aim of this paper was to study relationships between sensorial characteristics and physical properties to understand how different excipients affect these aspects, comparing one starch particle–stabilized and three surfactant-stabilized formulations. A human panel was used to evaluate sensorial perception, while physical properties were deduced by rheology and tactile friction, together with in vivo and ex vivo skin hydration measurements. The results show that sensorial attributes related to the application phase can be predicted with rheology, while afterfeel attributes can be predicted with tactile friction studies. Differences in rheological and sensory properties among surfactant-based creams could mainly be attributed to the type of emollients used, presence of thickeners and surfactant composition. Differences between surfactant-based creams and a Pickering cream were more evident in relation to the afterfeel perception. Presence of starch particles in the residual film on skin results in high tactile friction and low perception of residual coating, stickiness, greasiness, and slipperiness in sensorial afterfeel. © 2021 The Authors

Place, publisher, year, edition, pages
Elsevier B.V., 2022
Keywords
Modified starch, Pickering emulsions, Rheology, Sensory study, Surfactant-free formulations, Tactile friction, Topical creams, cosmetic, emollient agent, excipient, friction, human, skin, Cosmetics, Emollients, Excipients, Humans
National Category
Food Engineering
Identifiers
urn:nbn:se:ri:diva-59047 (URN)10.1016/j.ijpharm.2021.121370 (DOI)2-s2.0-85122426677 (Scopus ID)
Note

 Funding details: Stiftelsen för Kunskaps- och Kompetensutveckling, KKS; Funding details: Gustav Th. Ohlssons Fond; Funding text 1: We are grateful to the Knowledge foundation (Sweden) for funding the project, and Johan Engblom also thank the Gustaf Th Ohlsson foundation (Sweden) for financial support. Speximo AB is acknowledged for providing starch particles.

Available from: 2022-04-21 Created: 2022-04-21 Last updated: 2023-05-25Bibliographically approved
Ali, A., Ringstad, L., Skedung, L., Falkman, P., Wahlgren, M. & Engblom, J. (2022). Tactile friction of topical creams and emulsions: Friction measurements on excised skin and VitroSkin® using ForceBoard™. International Journal of Pharmaceutics, 615, Article ID 121502.
Open this publication in new window or tab >>Tactile friction of topical creams and emulsions: Friction measurements on excised skin and VitroSkin® using ForceBoard™
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2022 (English)In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 615, article id 121502Article in journal (Refereed) Published
Abstract [en]

Tactile perception can be investigated through ex vivo friction measurements using a so–called ForceBoard™, providing objective assessments and savings in time and money, compared to a subjective human panel. In this work we aim to compare excised skin versus VitroSkin® as model substrates for tactile friction measurements. A further aim is to detect possible differences between traditional surfactant-based creams, and a particle-stabilized (Pickering) cream and investigate how the different substrates affect the results obtained. It was found that the difference in tactile friction between excised skin and VitroSkin® was small on untreated substrates. When topical creams were applied, the same trends were observed for both substrates, although the frictional variation over time relates to the difference in surface structure between the two substrates. The results also confirmed that there is a difference between starch-based Pickering formulations and surfactant-based creams after application, indicating that the latter is greasier than Pickering cream. It was also shown that the tactile friction of Pickering emulsions was consistently high even with high amounts of oil, indicating a non-greasy, and non-sticky formulation. The characteristics of starch-stabilized Pickering formulations make them promising candidates in the development of surfactant-free topical formulations with unique tactile properties. © 2022 The Authors

Place, publisher, year, edition, pages
Elsevier B.V., 2022
Keywords
Excised skin, Force-Board™, Pickering emulsions, Surfactant-free formulations, Tactile friction, Topical creams, VitroSkin®
National Category
Food Engineering
Identifiers
urn:nbn:se:ri:diva-58500 (URN)10.1016/j.ijpharm.2022.121502 (DOI)2-s2.0-85123703718 (Scopus ID)
Note

 Funding details: Stiftelsen för Kunskaps- och Kompetensutveckling, KKS; Funding details: Gustav Th. Ohlssons Fond; Funding text 1: We are grateful to the Knowledge foundation (Sweden) for funding the project, and Johan Engblom also thank the Gustaf Th Olsson foundation (Sweden) for financial support. Speximo AB is acknowledged for providing starch particles.

Available from: 2022-02-18 Created: 2022-02-18 Last updated: 2023-05-25Bibliographically approved
Skedung, L., Hörlin, E., Harris, K. L., Rutland, M. W., Applebaum, M., Greaves, A. & Luengo, G. (2021). A Curly Q: Is Frizz a Matter of Friction?. Perception, 50(8), 728-732
Open this publication in new window or tab >>A Curly Q: Is Frizz a Matter of Friction?
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2021 (English)In: Perception, ISSN 0301-0066, E-ISSN 1468-4233, Vol. 50, no 8, p. 728-732Article in journal (Refereed) Published
Abstract [en]

The oft discussed and fretted over environmental influences on hair have led to a popular consensus which suggests that elevated temperature and humidity lead to frizzier, wilder hair. However, few attempts at actually quantifying these effects have been made. Although frizziness is usually perceived visually, here the influence of variations in temperature and humidity on the tactile perception and friction of curly and straight hair were investigated. It is shown that changes in humidity may disproportionately affect perceived frizziness of curly hair by touch due to concurrent changes in the tactile friction. © The Author(s) 2021.

Place, publisher, year, edition, pages
SAGE Publications Ltd, 2021
Keywords
environmental conditions, hair care, tactile friction, tactile perception
National Category
Physiology
Identifiers
urn:nbn:se:ri:diva-54705 (URN)10.1177/03010066211024442 (DOI)2-s2.0-85108305444 (Scopus ID)
Note

Funding text 1: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: GSL, MA and AG are full employees of L’Oréal involved in research activities. RISE Research Institutes of Sweden have received funding from L’Oréal to perform this research.; Funding text 2: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The majority of this work was financed by L’Oréal.

Available from: 2021-06-30 Created: 2021-06-30 Last updated: 2023-05-25Bibliographically approved
Harris, K. L., Collier, E. S., Skedung, L. & Rutland, M. W. (2021). A Sticky Situation or Rough Going?: Influencing Haptic Perception of Wood Coatings Through Frictional and Topographical Design. Tribology letters, 69(3), Article ID 113.
Open this publication in new window or tab >>A Sticky Situation or Rough Going?: Influencing Haptic Perception of Wood Coatings Through Frictional and Topographical Design
2021 (English)In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 69, no 3, article id 113Article in journal (Refereed) Published
Abstract [en]

Improving the tactile aesthetics of products that can be described as touch intensive is an increasing priority within many sectors, including the furniture industry. Understanding which physical characteristics contribute to the haptic experience of a surface, and how, is therefore highly topical. It has earlier been shown that both friction and topography affect tactile perception. Thus, two series of stimuli have been produced using standard coating techniques, with systematic variation in (physical) friction and roughness properties. This was achieved through appropriate selection of matting agents and resins. The stimuli sets were then evaluated perceptually to determine the extent to which discrimination between pairs of surfaces followed the systematic materials variation. In addition to investigating the role of the physical properties in discrimination of the surfaces, their influence on perceived pleasantness and naturalness was also studied. The results indicate that changes in tactile perception can be understood in terms of friction and roughness, and that varying the matting agents (topography) and resins (material properties) in the coatings provide the controlling factors for furniture applications. Perceived pleasantness is associated with low friction and smoother topography, whilst perceived naturalness is found to be described by an interaction between tactile friction and the average maximum peak height of the surface features. Graphic Abstract: [Figure not available: see fulltext.] © 2021, The Author(s).

Place, publisher, year, edition, pages
Springer, 2021
Keywords
Haptic perception, Psychophysics, Psychotribology, Tactile friction, Coatings, Resins, Surface roughness, Topography, Controlling factors, Furniture industry, Matting agents, Physical characteristics, Surface feature, Systematic variation, Tactile perception, Friction
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:ri:diva-56010 (URN)10.1007/s11249-021-01485-z (DOI)2-s2.0-85112132029 (Scopus ID)
Note

 Funding text 1: This work is an extract from a project predominantly financed by IKEA of Sweden AB and Akzo Nobel Coatings International B.V. We extend our thanks anonymously to all of the people there who contributed with practical assistance, materials choices and supported the concept.; Funding text 2: Open access funding provided by Royal Institute of Technology. This work is an extract from a project predominantly financed by IKEA of Sweden AB and Akzo Nobel Coatings International B.V.

Available from: 2021-08-25 Created: 2021-08-25 Last updated: 2023-05-25Bibliographically approved
Skedung, L., Collier, E. S., Harris, K. L., Wallqvist, V., Nyhus, A. K. & Björndal, L. (2021). FINE-TUNING THE TACTILE PERCEPTION OF COATINGS. European Coatings Journal, 6, 32-37
Open this publication in new window or tab >>FINE-TUNING THE TACTILE PERCEPTION OF COATINGS
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2021 (English)In: European Coatings Journal, ISSN 0930-3847, Vol. 6, p. 32-37Article in journal (Other academic) Published
Abstract [en]

Human tactile evaluations were combined with tactile friction measurements to quantify the perceptual experience of touching coated panels. Monosized beads of nine different polymer compositions were added to a soft-touch waterborne two-component PUR coating. Introducing beads of different composition affected tactile perception.

National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:ri:diva-57519 (URN)
Available from: 2022-01-03 Created: 2022-01-03 Last updated: 2023-06-08Bibliographically approved
Jin, R., Skedung, L., Cazeneuve, C., Chang, J. C., Rutland, M. W., Ruths, M. & Luengo, G. S. (2020). Bioinspired Self-Assembled 3D Patterned Polymer Textures as Skin Coatings Models: Tribology and Tactile Behavior. Biotribology, 24, Article ID 100151.
Open this publication in new window or tab >>Bioinspired Self-Assembled 3D Patterned Polymer Textures as Skin Coatings Models: Tribology and Tactile Behavior
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2020 (English)In: Biotribology, ISSN 2352-5738, Vol. 24, article id 100151Article in journal (Refereed) Published
Abstract [en]

It is well known that during evolution, specific surface patterns emerged (e.g., on lotus leaves and butterfly wings) endowed with many remarkable surface properties (superhydrophobicity, vibrant structural color, delicate textures, etc.). In order to obtain these natural effects in cosmetics, we look for ways to transfer topographic patterns in coatings and treatments. Textured polymer surfaces were studied to explore their friction properties on the microscale and possible correlations with human tactile friction on the macroscale. We have chosen self-assembling block and random copolymers as model systems to prepare reliable biomimetic films with different micrometer and nanometer scale randomly patterned and randomly rough surfaces. The surface texture of the films was characterized by atomic force microscopy (AFM), and their tribological (friction) properties were studied with a surface forces apparatus (SFA) at a low sliding speed of 3 μm/s and at a speed of 10 cm/s relevant to realistic applications. The results are evaluated in terms of polymer segment mobility, interpenetration, entanglement and relaxation at interfaces, surface texture as described by roughness parameters, and interlocking of asperities. A stiction spike (static friction) was commonly found for the randomly patterned glassy polymer films. Random roughness patterns made from semi-crystalline polymers above their Tg gave high friction at low speed, but their friction coefficients were reduced at high speed due to less time for local entanglement and relaxations. The friction response of one of them was also affected differently by humidity than that of glassy polymer films. Tactile friction measurements with a human finger sliding against the polymer films revealed that the textures also provided differences at the macroscale, although the dynamic changes possibly due to lipid transfer, occlusion of moisture and/or damage of the films makes it difficult to draw robust conclusions. Finally, as an example, it is shown that these textures can be transferred to a soft elastomeric skin mimic substrate. This study introduces the concept of surface patterning by self-assembly to deliver tactile sensorial properties in coatings.

Place, publisher, year, edition, pages
Elsevier Ltd., 2020
Keywords
Atomic force microscopy, Polymer self-assembly, Roughness, Skin model, Surface forces apparatus, Surface texture, Tactile friction, Tribology
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-50964 (URN)10.1016/j.biotri.2020.100151 (DOI)2-s2.0-85096177812 (Scopus ID)
Note

Funding text 1: CC, JCC, and GSL are full time employees of L’Oréal. RJ, LS, MWR, and MR have received funding from L’Oréal Research and Innovation.; Funding text 2: We would like to thank J. Israelachvili for helpful discussions in the early stages of the project and for his mentoring of MR and GSL. We also thank K. Kristiansen and J. Scott of SurForce LLC for their assistance with the high speed SFA attachment, and X. Xu for help with sample preparation. This project was supported by L'Oreal Research and Innovation.

Available from: 2020-12-17 Created: 2020-12-17 Last updated: 2023-05-25Bibliographically approved
Skedung, L., Harris, K. L., Hörlin, E. & Rutland, M. W. (2020). The finishing touches: the role of friction and roughness in haptic perception of surface coatings.. Experimental Brain Research, 238, 1511-1524
Open this publication in new window or tab >>The finishing touches: the role of friction and roughness in haptic perception of surface coatings.
2020 (English)In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 238, p. 1511-1524Article in journal (Refereed) Published
Abstract [en]

Humans are extraordinarily skilled in the tactile evaluation of, and differentiation between, surfaces. The chemical and mechanical properties of these surfaces are translated into tactile signals during haptic exploration by mechanoreceptors in our skin, which are specialized to respond to different types of temporal and mechanical stimulation. Describing the effects of measurable physical characteristics on the human response to tactile exploration of surfaces is of great interest to manufacturers of household materials so that the haptic experience can be considered during design, product development and quality control. In this study, methods from psychophysics and materials science are combined to advance current understanding of which physical properties affect tactile perception of a range of furniture surfaces, i.e., foils and coatings, thus creating a tactile map of the furniture product landscape. Participants' responses in a similarity scaling task were analyzed using INDSCAL from which three haptic dimensions were identified. Results show that specific roughness parameters, tactile friction and vibrational information, as characterized by a stylus profilometer, a Forceboard, and a biomimetic synthetic finger, are important for tactile differentiation and preferences of these surface treatments. The obtained dimensions are described as distinct combinations of the surface properties characterized, rather than as 'roughness' or 'friction' independently. Preferences by touch were related to the roughness, friction and thermal properties of the surfaces. The results both complement and advance current understanding of how roughness and friction relate to tactile perception of surfaces.

Keywords
Friction, Haptic perception, Psychotribology, Roughness, Touch, Wood furniture surfaces
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-45039 (URN)10.1007/s00221-020-05831-w (DOI)32447410 (PubMedID)
Available from: 2020-05-29 Created: 2020-05-29 Last updated: 2023-05-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6657-1592

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