This study investigates the neural and behavioral mechanisms of tactile perceptual discrimination using fMRI and a set of wrinkled surface stimuli with varying textures. Fifteen female participants were tasked with distinguishing between different surfaces by touch alone. Behavioral results demonstrated variable discriminability across conditions, reflecting the tactile sensitivity of human fingertips. Neural analysis showed varied brain activations tied to the task’s difficulty. In the easiest least fine-grained discrimination condition, widespread activations were observed across sensory and integration regions. As task difficulty increased, stronger parietal and frontal lobe involvement reflected higher cognitive demands. In the hardest most fine-grained discrimination condition, activation concentrated in the right frontal lobe, indicating reliance on executive functions. These results highlight the brain’s intricate role in processing sensory information during tactile discrimination tasks of varying difficulty. As task difficulty increases, the brain adapts by engaging additional neural resources to meet higher cognitive demands. This research advances our understanding of the psychophysical and neural bases of tactile discrimination acuity, with practical implications for designing materials that enhance tactile feedback.

The demands on chemical industry to transform towards safety and sustainability will require multi-disciplinary research and development where experts on chemistry and chemical engineering, toxicology, ecotoxicology, and life cycle assessment collaborate to develop novel production methods, chemicals and materials. Here we summarise the results of the Mistra SafeChem programme which has yielded considerable output in the areas of catalysis/bio-catalysis, hazard screening for humans and ecosystems and life cycle assessment with chemical footprints, both as individual scientific achievements and as part of an integrated approach to assess safety and sustainability of novel chemicals and chemical synthesis processes, in chemical value chains and across collaborations between industry- academia/ industry-industry. The outcomes from the programme are summarised and discussed and experiences from dialogues on the future of safe and sustainable chemistry are presented

The unique properties of per- and polyfluoroalkyl substances (PFAS) have led to their extensive use in consumer products, including ski wax. Based on the risks associated with PFAS, and to align with PFAS regulations, the international ski federation (FIS) implemented a ban on products containing “C8 fluorocarbons/perfluorooctanoate (PFOA)” at all FIS events from the 2021/2022 season, leading manufactures to shift their formulations towards short-chain PFAS chemistries. To date, most studies characterising PFAS in ski waxes have measured a suite of individual substances using targeted analytical approaches. However, the fraction of total fluorine (TF) in the wax accounted for by these substances remains unclear. In this study, we sought to address this question by applying a multi-platform, fluorine mass balance approach to a total of 10 commercially available ski wax products. Analysis of TF by combustion ion chromatography (CIC) revealed concentrations of 1040–51700 μg F g−1 for the different fluorinated waxes. In comparison, extractable organic fluorine (EOF) determined in methanol extracts by CIC (and later confirmed by inductively-coupled plasma-mass spectrometry and 19F- nuclear magnetic resonance spectroscopy) ranged from 92 to 3160 μg g−1, accounting for only 3–8.8 % of total fluorine (TF). Further characterisation of extracts by cyclic ion mobility-mass spectrometry (IMS) revealed 15 individual PFAS with perfluoroalkyl carboxylic acid concentrations up to 33 μg F g−1, and 3 products exceeding the regulatory limit for PFOA (0.025 μg g−1) by a factor of up to 100. The sum of all PFAS accounted for only 0.01–1.0 % of EOF, implying a high percentage of unidentified PFAS, thus, pyrolysis gas chromatography-mass spectrometry was used to provide evidence of the nature of the non-extractable fluorine present in the ski wax products. 

Replacing petroleum-based with bio-based ingredients in articles and chemical products is one important step towards reducing the environmental impact, and promoting circular economy practices, aligning with the goal “Responsible Consumption and Production” within United Nations’ Agenda 2030. The aim of the project was to develop bio-based prototype ski waxes and to evaluate and benchmark them with commercial petroleum-based PFAS-free ski waxes, in terms of hydrophobicity, glide performance and biodegradation.

Bio-based ski wax prototypes were blended using a mixture of ingredients approved for either topical application or ingestion by humans. Which ingredients and relative ratios to mix were based on melting points, general hydrophobic properties and generated knowledge from testing of earlier prototypes. It should be noted that only Vallakokerskan has the information about the exact content in the ski wax prototypes.

The hypothesis is that more hydrophobic, i.e. more water repellent, ski wax allows better transportation of the water film away from the ski/snow interface, providing lower friction and better glide. The hydrophobicity of ski waxes and ingredients was quantified from contact angle measurements using water and ethylene glycol as the liquid in a climate-controlled room (23°C and 50% relative humidity). To measure contact angles at sub-zero degrees, a less sensitive but portable device was put in a freezer room at -5°C where contact angles were measured using ethylene glycol.

The ski waxes showed similar hydrophobicity, in the measured static, advancing and receding contact angles, both in room temperature and at -5°C. However, the roll-off angle when the water droplet started to roll, was slightly lower for the commercial ski waxes than the bio-based prototypes. Greater differences in hydrophobicity and roll-off angles were observed for the ingredients compared to the ski wax.

In the glide tests on snow, it was difficult to separate the bio-based and commercial ski wax. This was both when considering the total glide time from four skiers testing each ski wax (ski pair) twice, and in the pairwise comparisons as is normally done when selecting skis before competition. These results show that the bio-based prototypes are comparable to commercial ski wax that is used both for competition and recreational skiing. While having similar glide function, the advantage of the bio-based ski wax is that it contains only naturally derived ingredients and that it seems to degrade slightly more rapidly in the environment. The biodegradation was compared between one bio-based and one petroleum-based ski wax using a respiration test where formed CO₂ was quantified over time. The estimated number of days required for complete degradation of the bio-based ski wax and commercial ski wax would be 223 days and 335 days, respectively, if the degradation continues at the same rate and if all carbon is converted to CO₂. In comparison to cellulose, both ski waxes degrade relatively slowly, most likely due to their hydrophobic properties.

During the project it was decided to also quantify and compare the hardness of the waxes since that is being discussed more and more as one additional characterisation technique in the project. The hardness measurements were done at -5°C. The maximum force encountered (firmness) when a probe was lowered into the sample during the compression test was taken as the hardness. Differences were obtained between the samples where the average firmness (hardness) was higher for the commercial green, blue and purple commercial ski waxes compared to the corresponding bio-based wax. However, the bio-based yellow was harder than the corresponding yellow commercial ski wax. Large differences in hardness at -5°C for the ingredients were noted.

The prototypes have been made with a mixture of different ingredients. The results from the hydrophobicity and hardness measurements of ingredients, can be used to select and modify the relative amount of each ingredient in the ski wax. If the hypothesis is that more hydrophobic and harder ingredients are better for the glide, it could be interesting to see if a wax containing a higher amount of those harder and more hydrophobic ingredients could increase the performance.

The focus in this project has been to develop a bio-based ski wax matrix. As a next step it would be interesting to develop and incorporate bio-based additives to try to increase the performance further. Another future outlook is to make the bio-based wax as a liquid product that are becoming more popular due the ease of application and less waste during the waxing procedure.

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.

The interaction of active substances with molecular structures in stratum corneum (SC) is crucial for the efficacy and safety of cosmetic formulations and topical drugs. However, the molecular architecture of SC is highly complex and methods to unambiguously localize exogenous molecules within SC are lacking. Consequently, little is known about the distribution of actives within SC, and proposed penetration mechanisms through SC are typically limited to simple diffusion via a tortuous (lipid only) or transverse (across corneocytes and lipid matrix) pathway. In this work, 3D mass spectrometry imaging is used to determine the spatial distributions of four active substances at subcellular resolution in SC, including partitioning between the corneocytes and the intercellular lipid matrix. The results indicate that caffeine, 2-methyl resorcinol and oxybenzone are homogeneously distributed in the corneocytes but largely absent in the lipid matrix, despite considerable differences in lipophilicity. In contrast, the distribution- of jasmonic acid derivative is more inhomogeneous and indicates considerable localization to both the lipid phase and the corneocytes.

The environmental impact is a strong incentive for the development of upcycling processes for textile waste. However, toxic chemicals may occur in both brand-new textiles and post-consumer garments, and the chemical transfer in such routes is important to investigate. The present study applied non-target screening and quantification with liquid chromatography/mass spectrometry to follow the fate of hazardous chemicals from post-consumer polycotton garments to a new material, cellulose nanocrystals, in a chemical upcycling utilizing strongly acidic conditions. The majority of hazardous chemicals detected within the process were found to be transferred to a residual of polyester material and not to the enriched cellulose. However, phthalates were found to be mainly attached to the cellulose nanocrystals. The detected total concentration, in this case, was below 5 μg/g, at least 200 times lower than the limit set by the European Union. This indicates the importance of monitoring and controlling the phthalate content in the starting material of the process, i.e., the post-consumer garments. The chemical release into the process waste effluent could be estimated based on water solubility data for chemicals under the applied conditions. Three compounds, the water-repellent substance perfluorooctanesulfonic acid and the dyes Crystal Violet and Victoria Pure Blue, were almost entirely transferred into the process waste effluent. Although the levels detected were very low in the present pilot process, their presence eventually indicates the need for wastewater purification at further upscaling, depending on the exposure and dose in relation to toxicological relevant thresholds. 

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.

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.