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  • 1.
    Aadland, Reidun C.
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Akarri, Salem
    NTNU Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. NTNU Norwegian University of Science and Technology, Norway.
    Torsæter, Ole
    NTNU Norwegian University of Science and Technology, Norway.
    A core flood and microfluidics investigation of nanocellulose as a chemical additive to water flooding for eor2020In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 7, article id 1296Article in journal (Refereed)
    Abstract [en]

    Cellulose nanocrystals (CNCs) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)- oxidized cellulose nanofibrils (T-CNFs) were tested as enhanced oil recovery (EOR) agents through core floods and microfluidic experiments. Both particles were mixed with low salinity water (LSW). The core floods were grouped into three parts based on the research objectives. In Part 1, secondary core flood using CNCs was compared to regular water flooding at fixed conditions, by reusing the same core plug to maintain the same pore structure. CNCs produced 5.8% of original oil in place (OOIP) more oil than LSW. For Part 2, the effect of injection scheme, temperature, and rock wettability was investigated using CNCs. The same trend was observed for the secondary floods, with CNCs performing better than their parallel experiment using LSW. Furthermore, the particles seemed to perform better under mixed-wet conditions. Additional oil (2.9–15.7% of OOIP) was produced when CNCs were injected as a tertiary EOR agent, with more incremental oil produced at high temperature. In the final part, the effect of particle type was studied. T-CNFs produced significantly more oil compared to CNCs. However, the injection of T-CNF particles resulted in a steep increase in pressure, which never stabilized. Furthermore, a filter cake was observed at the core face after the experiment was completed. Microfluidic experiments showed that both T-CNF and CNC nanofluids led to a better sweep efficiency compared to low salinity water flooding. T- CNF particles showed the ability to enhance the oil recovery by breaking up events and reducing the trapping efficiency of the porous medium. A higher flow rate resulted in lower oil recovery factors and higher remaining oil connectivity. Contact angle and interfacial tension measurements were conducted to understand the oil recovery mechanisms. CNCs altered the interfacial tension the most, while T-CNFs had the largest effect on the contact angle. However, the changes were not significant enough for them to be considered primary EOR mechanisms.

  • 2.
    Aadland, Reidun C.
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Dziuba, Carter J.
    University of Calgary, Canada.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI.
    Torsæter, Ole
    NTNU Norwegian University of Science and Technology, Norway.
    Holt, Thorleif
    SINTEF, Norway.
    Gates, Ian D.
    University of Calgary, Canada.
    Bryant, Steven L.
    University of Calgary, Canada.
    Identification of nanocellulose retention characteristics in porous media2018In: Nanomaterials, E-ISSN 2079-4991, Vol. 8, no 7, article id 547Article in journal (Refereed)
    Abstract [en]

    The application of nanotechnology to the petroleum industry has sparked recent interest in increasing oil recovery, while reducing environmental impact. Nanocellulose is an emerging nanoparticle that is derived from trees or waste stream from wood and fiber industries. Thus, it is taken from a renewable and sustainable source, and could therefore serve as a good alternative to current Enhanced Oil Recovery (EOR) technologies. However, before nanocellulose can be applied as an EOR technique, further understanding of its transport behavior and retention in porous media is required. The research documented in this paper examines retention mechanisms that occur during nanocellulose transport. In a series of experiments, nanocellulose particles dispersed in brine were injected into sandpacks and Berea sandstone cores. The resulting retention and permeability reduction were measured. The experimental parameters that were varied include sand grain size, nanocellulose type, salinity, and flow rate. Under low salinity conditions, the dominant retention mechanism was adsorption and when salinity was increased, the dominant retention mechanism shifted towards log-jamming. Retention and permeability reduction increased as grain size decreased, which results from increased straining of nanocellulose aggregates. In addition, each type of nanocellulose was found to have significantly different transport properties. Experiments with Berea sandstone cores indicate that some pore volume was inaccessible to the nanocellulose. As a general trend, the larger the size of aggregates in bulk solution, the greater the observed retention and permeability reduction. Salinity was found to be the most important parameter affecting transport. Increased salinity caused additional aggregation, which led to increased straining and filter cake formation. Higher flow rates were found to reduce retention and permeability reduction. Increased velocity was accompanied by an increase in shear, which is believed to promote breakdown of nanocellulose aggregates. © 2018 by the authors.

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  • 3.
    Aadland, Reidun
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Jakobsen, Trygve
    NTNU Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Long-Sanouiller, Haili
    NTNU Norwegian University of Science and Technology, Norway.
    Simon, Sebastien
    NTNU Norwegian University of Science and Technology, Norway.
    Paso, Kristofer
    NTNU Norwegian University of Science and Technology, Norway.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. NTNU Norwegian University of Science and Technology, Norway.
    Torsæter, Ole
    NTNU Norwegian University of Science and Technology, Norway.
    High-temperature core flood investigation of nanocellulose as a green additive for enhanced oil recovery2019In: Nanomaterials, E-ISSN 2079-4991, Vol. 9, no 5, article id 665Article in journal (Refereed)
    Abstract [en]

    Recent studies have discovered a substantial viscosity increase of aqueous cellulose nanocrystal (CNC) dispersions upon heat aging at temperatures above 90 °C. This distinct change in material properties at very low concentrations in water has been proposed as an active mechanism for enhanced oil recovery (EOR), as highly viscous fluid may improve macroscopic sweep efficiencies and mitigate viscous fingering. A high-temperature (120 °C) core flood experiment was carried out with 1 wt.% CNC in low salinity brine on a 60 cm-long sandstone core outcrop initially saturated with crude oil. A flow rate corresponding to 24 h per pore volume was applied to ensure sufficient viscosification time within the porous media. The total oil recovery was 62.2%, including 1.2% oil being produced during CNC flooding. Creation of local log-jams inside the porous media appears to be the dominant mechanism for additional oil recovery during nano flooding. The permeability was reduced by 89.5% during the core flood, and a thin layer of nanocellulose film was observed at the inlet of the core plug. CNC fluid and core flood effluent was analyzed using atomic force microscopy (AFM), particle size analysis, and shear rheology. The effluent was largely unchanged after passing through the core over a time period of 24 h. After the core outcrop was rinsed, a micro computed tomography (micro-CT) was used to examine heterogeneity of the core. The core was found to be homogeneous. © 2019 by the authors.

  • 4.
    Aaen, Ragnhild
    et al.
    Norwegian University of Science and Technology, Norway.
    Brodin, Fredrik Wernersson
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI.
    Simon, Sébastien
    Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, PFI. Norwegian University of Science and Technology, Norway.
    Oil-in-Water Emulsions Stabilized by Cellulose Nanofibrils-The Effects of Ionic Strength and pH.2019In: Nanomaterials, E-ISSN 2079-4991, Vol. 9, no 2, article id E259Article in journal (Refereed)
    Abstract [en]

    Pickering o/w emulsions prepared with 40 wt % rapeseed oil were stabilized with the use of low charged enzymatically treated cellulose nanofibrils (CNFs) and highly charged 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized CNFs. The emulsion-forming abilities and storage stability of the two qualities were tested in the presence of NaCl and acetic acid, at concentrations relevant to food applications. Food emulsions may be an important future application area for CNFs due to their availability and excellent viscosifying abilities. The emulsion characterization was carried out by visual inspection, light microscopy, viscosity measurements, dynamic light scattering and mild centrifugation, which showed that stable emulsions could be obtained for both CNF qualities in the absence of salt and acid. In addition, the enzymatically stabilized CNFs were able to stabilize emulsions in the presence of acid and NaCl, with little change in the appearance or droplet size distribution over one month of storage at room temperature. The work showed that enzymatically treated CNFs could be suitable for use in food systems where NaCl and acid are present, while the more highly charged TEMPO-CNFs might be more suited for other applications, where they can contribute to a high emulsion viscosity even at low concentrations.

  • 5.
    Berktas, Ilayda
    et al.
    Sabanci University, Turkey.
    Chaudhari, Ojas
    RISE Research Institutes of Sweden, Built Environment, Infrastructure and concrete technology.
    Ghafar, Ali N
    RISE Research Institutes of Sweden.
    Menceloglu, Yusuf
    Sabanci University, Turkey.
    Okan, Burcu
    Sabanci University, Turkey.
    Silanization of SiO2 decorated carbon nanosheets from rice husk ash and its effect on workability and hydration of cement grouts2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 3, article id 655Article in journal (Refereed)
    Abstract [en]

    Rice husk ash (RHA) having a porous sructure and a high amount of amorphous silica nanoparticles (4 nm) decorated on the surface of carbon nanosheets is a suitable and cheap candidate for the use of a grout additive. In this study, neat RHA and functionalized RHA (f-RHA) with three different loadings were successfully incorporated into the cement-bentonite based grouts by adjusting the water to cement ratio. The workability of the developed grouts having RHA-based additives was analyzed in terms of bleeding, density, flow spread, and Marsh cone time. Additionally, the thermal and prolongation of hydration performances of the cementitious grout were enriched by successful attachment of amino-silane functional groups on the RHA surface. The heat of hydration performances of RHA and functionalized RHA introduced cementitious grout composite were assessed by isothermal calorimetry tests, and especially the kinetics of hydration was increased by the addition of RHA. The presence of amino silane groups in f-RHA intensified the heat adsorption by reacting with cement constituents, and thus resulted in the retardation and reduction in the heat flow. Therefore, using an amino-silane coupling agent increased the induction period and hindered the heat of hydration compared to the reference grout. On the other hand, the incorporation of RHA and f-RHA into the cement matrix did not affect the thermal conductivity of the grouts. © 2021 by the authors. 

  • 6.
    Blomgren, Jakob
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Ahrentorp, Fredrik
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Ilver, Dag
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Jonasson, Christian
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Sepehri, Sobhan
    Chalmers University of Technology, Sweden.
    Kalaboukhov, Alexei
    Chalmers University of Technology, Sweden.
    Winkler, Dag
    Chalmers University of Technology, Sweden.
    de la Torre, Tereza
    Uppsala University, Sweden.
    Strømme, Maria
    Uppsala University, Sweden.
    Johansson, Christer
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Development of a sensitive induction-based magnetic nanoparticle biodetection method2018In: Nanomaterials, E-ISSN 2079-4991, Vol. 8, no 11, article id 887Article in journal (Refereed)
    Abstract [en]

    We developed a novel biodetection method for influenza virus based on AC magnetic susceptibility measurement techniques (the DynoMag induction technique) together with functionalized multi-core magnetic nanoparticles. The sample consisting of an incubated mixture of magnetic nanoparticles and rolling circle amplified DNA coils is injected into a tube by a peristaltic pump. The sample is moved as a plug to the two well-balanced detection coils and the dynamic magnetic moment in each position is read over a range of excitation frequencies. The time for making a complete frequency sweep over the relaxation peak is about 5 minutes (10 Hz–10 kHz with 20 data points). The obtained standard deviation of the magnetic signal at the relaxation frequency (around 100 Hz) is equal to about 10−5 (volume susceptibility SI units), which is in the same range obtained with the DynoMag system. The limit of detection with this method is found to be in the range of 1 pM.

  • 7.
    Campodoni, E.
    et al.
    CNR National Research Council, Italy.
    Montanari, M.
    CNR National Research Council, Italy.
    Dozio, S. M.
    CNR National Research Council, Italy.
    Heggset, Ellinor B
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Panseri, S.
    CNR National Research Council, Italy.
    Montesi, M.
    CNR National Research Council, Italy.
    Tampieri, A.
    CNR National Research Council, Italy.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. NTNU Norwegian University of Science and Technology, Norway.
    Sandri, M.
    CNR National Research Council, Italy.
    Blending gelatin and cellulose nanofibrils: Biocomposites with tunable degradability and mechanical behavior2020In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 6, article id 1219Article in journal (Refereed)
    Abstract [en]

    Many studies show how biomaterial properties like stiffness, mechanical stimulation and surface topography can influence cellular functions and direct stem cell differentiation. In this work, two different natural materials, gelatin (Gel) and cellulose nanofibrils (CNFs), were combined to design suitable 3D porous biocomposites for soft-tissue engineering. Gel was selected for its well-assessed high biomimicry that it shares with collagen, from which it derives, while the CNFs were chosen as structural reinforcement because of their exceptional mechanical properties and biocompatibility. Three different compositions of Gel and CNFs, i.e., with weight ratios of 75:25, 50:50 and 25:75, were studied. The biocomposites were morphologically characterized and their total-and macro-porosity assessed, proving their suitability for cell colonization. In general, the pores were larger and more isotropic in the biocomposites compared to the pure materials. The influence of freeze-casting and dehydrothermal treatment (DHT) on mechanical properties, the absorption ability and the shape retention were evaluated. Higher content of CNFs gave higher swelling, and this was attributed to the pore structure. Cross-linking between CNFs and Gel using DHT was confirmed. The Young’s modulus increased significantly by adding the CNFs to Gel with a linear relationship with respect to the CNF amounts. Finally, the biocomposites were characterized in vitro by testing cell colonization and growth through a quantitative cell viability analysis performed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, the cell viability analysis was performed by the means of a Live/Dead test with Human mesenchymal stem cells (hMSCs). All the biocomposites had higher cytocompatibility compared to the pure materials, Gel and CNFs. © 2020 by the authors. 

  • 8.
    González-Gil, Rosa
    et al.
    Leitat Technological Center, Spain; Catalan Institute of Nanoscience and Nanotechnology, Spain.
    Borràs, Mateu
    Leitat Technological Center, Spain; Arkyne Technologies SL, Spain.
    Chbani, Aiman
    Leitat Technological Center, Spain;.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Aulin, Christian
    RISE Research Institutes of Sweden. Holmen Iggesund, Sweden.
    Aucher, Christophe
    Leitat Technological Center, Spain;.
    Martínez-Crespiera, Sandra
    Leitat Technological Center, Spain.
    Sustainable and Printable Nanocellulose-Based Ionogels as Gel Polymer Electrolytes for Supercapacitors2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 2, article id 273Article in journal (Refereed)
    Abstract [en]

    A new gel polymer electrolyte (GPE) based supercapacitor with an ionic conductivity up to 0.32–0.94 mS cm−2 has been synthesized from a mixture of an ionic liquid (IL) with nanocellulose (NC). The new NC-ionogel was prepared by combining the IL 1-ethyl-3-methylimidazolium dimethyl phosphate (EMIMP) with carboxymethylated cellulose nanofibers (CNFc) at different ratios (CNFc ratio from 1 to 4). The addition of CNFc improved the ionogel properties to become easily printable onto the electrode surface. The new GPE based supercapacitor cell showed good electrochemical performance with specific capacitance of 160 F g−1 and an equivalent series resistance (ESR) of 10.2 Ω cm−2 at a current density of 1 mA cm−2. The accessibility to the full capacitance of the device is demonstrated after the addition of CNFc in EMIMP compared to the pristine EMIMP (99 F g−1 and 14.7 Ω cm−2). © 2022 by the authors. 

  • 9.
    Jacobsen, Eirik Ulsaker
    et al.
    NTNU, Norway.
    Følkner, Simen Prang
    Norske Skog Saugbrugs, Norway.
    Blindheim, Jørgen
    NTNU, Norway.
    Molteberg, Dag
    Norske Skog Saugbrugs, Norway.
    Steinert, Martin
    NTNU, Norway.
    Chinga Carrasco, Gary
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    The Effect of Cellulose Nanofibres on Dewatering during Wet-Forming and the Mechanical Properties of Thermoformed Specimens Made of Thermomechanical and Kraft Pulps2023In: Nanomaterials, E-ISSN 2079-4991, Vol. 13, no 18, article id 2511Article in journal (Refereed)
    Abstract [en]

    Due to environmental concerns regarding single-use plastic materials, major efforts are being made to develop new material concepts based on biodegradable and renewable resources, e.g., wood pulp. In this study, we assessed two types of wood pulp fibres, i.e., thermomechanical pulp (TMP) and Kraft pulp fibres, and tested the performance of the fibres in wet-moulding and thermopressing trials. Kraft pulp fibres appeared to retain more water than TMP, increasing the dewatering time during wet-moulding and apparently increasing the compression resistance of the pulp during thermoforming. Additionally, cellulose nanofibres (CNF) were added to the pulps, which improved the mechanical properties of the final thermopressed specimens. However, the addition of CNF to the pulps (from 2 to 6%) had a further decrease in the dewatering efficiency in the wet-moulding process, and this effect was more pronounced in the Kraft pulp specimens. The mechanical performance of the thermoformed specimens was in the same range as the plastic materials that are conventionally used in food packaging, i.e., modulus 0.6–1.2 GPa, strength 49 MPa and elongation 6–9%. Finally, this study demonstrates the potential of wood pulps to form three-dimensional thermoformed products. 

  • 10.
    McCarrick, Sarah
    et al.
    Karolinska Institute, Sweden .
    Cappellini, Francesca
    Karolinska Institute, Sweden .
    Kessler, Amanda
    KTH Royal Institute of Technology, Sweden.
    Moelijker, Nynke
    Toxys, Netherlands.
    Derr, Remco
    Toxys, Netherlands.
    Hedberg, Jonas
    KTH Royal Institute of Technology, Sweden.
    Wold, Susanna
    KTH Royal Institute of Technology, Sweden.
    Blomberg, Eva
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. KTH Royal Institute of Technology, Sweden.
    Odnevall Wallinder, Inger
    KTH Royal Institute of Technology, Sweden.
    Hendriks, Giel
    Toxys, Netherlands.
    Karlsson, Hanna L
    Karolinska Institute, Sweden .
    ToxTracker Reporter Cell Lines as a Tool for Mechanism-Based (geno)Toxicity Screening of Nanoparticles-Metals, Oxides and Quantum Dots.2020In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 1, article id E110Article in journal (Refereed)
    Abstract [en]

    The increased use of nanoparticles (NPs) requires efficient testing of their potential toxic effects. A promising approach is to use reporter cell lines to quickly assess the activation of cellular stress response pathways. This study aimed to use the ToxTracker reporter cell lines to investigate (geno)toxicity of various metal- or metal oxide NPs and draw general conclusions on NP-induced effects, in combination with our previous findings. The NPs tested in this study (n = 18) also included quantum dots (QDs) in different sizes. The results showed a large variation in cytotoxicity of the NPs tested. Furthermore, whereas many induced oxidative stress only few activated reporters related to DNA damage. NPs of manganese (Mn and Mn3O4) induced the most remarkable ToxTracker response with activation of reporters for oxidative stress, DNA damage, protein unfolding and p53-related stress. The QDs (CdTe) were highly toxic showing clearly size-dependent effects and calculations suggest surface area as the most relevant dose metric. Of all NPs investigated in this and previous studies the following induce the DNA damage reporter; CuO, Co, CoO, CdTe QDs, Mn, Mn3O4, V2O5, and welding NPs. We suggest that these NPs are of particular concern when considering genotoxicity induced by metal- and metal oxide NPs.

  • 11.
    Nissilä, Tuukka
    et al.
    University of Oulu, Finland.
    Wei, Jiayuan
    Luleå University of Technology, Sweden.
    Geng, Shiyu
    Luleå University of Technology, Sweden.
    Teleman, Anita
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Oksman, Kristiina
    Luleå University of Technology, Sweden;University of Toronto, Canada.
    Ice-templated cellulose nanofiber filaments as a reinforcement material in epoxy composites2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 2, article id 490Article in journal (Refereed)
    Abstract [en]

    Finding renewable alternatives to the commonly used reinforcement materials in composites is attracting a significant amount of research interest. Nanocellulose is a promising candidate owing to its wide availability and favorable properties such as high Young’s modulus. This study addressed the major problems inherent to cellulose nanocomposites, namely, controlling the fiber structure and obtaining a sufficient interfacial adhesion between nanocellulose and a non-hydrophilic matrix. Unidirectionally aligned cellulose nanofiber filament mats were obtained via ice-templating, and chemical vapor deposition was used to cover the filament surfaces with an aminosilane before impregnating the mats with a bio-epoxy resin. The process resulted in cellulose nanocomposites with an oriented structure and a strong fiber–matrix interface. Diffuse reflectance infrared Fourier transform and X-ray photoelectron spectroscopy studies revealed the presence of silane on the filaments. The improved interface, resulting from the surface treatment, was observable in electron microscopy images and was further confirmed by the significant increase in the tan delta peak temperature. The storage modulus of the matrix could be improved up to 2.5-fold with 18 wt% filament content and was significantly higher in the filament direction. Wide-angle X-ray scattering was used to study the orientation of cellulose nanofibers in the filament mats and the composites, and the corresponding orientation indices were 0.6 and 0.53, respectively, indicating a significant level of alignment. © 2021 by the authors.

  • 12.
    Palladino, Nicoletta
    et al.
    Swedish National Heritage Board, Sweden.
    Hacke, Marei
    Swedish National Heritage Board, Sweden.
    Poggi, Giovanna
    University of Florence, Italy.
    Nechyporchuk, Oleksandr
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles. Chalmers University of Technology, Sweden.
    Kolman, Krzysztof
    Chalmers University of Technology, Sweden; Nouryon, Sweden.
    Xu, Qingmeng
    University of Florence, Italy.
    Persson, Michael E.
    Chalmers University of Technology, Sweden; Nouryon, Sweden.
    Giorgi, Rodorico
    University of Florence, Italy.
    Holmberg, Krister
    Chalmers University of Technology, Sweden.
    Baglioni, Piero
    University of Florence, Italy.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    Nanomaterials for combined stabilisation and deacidification of cellulosic materials: the case of iron-tannate dyed cotton2020In: Nanomaterials, E-ISSN 2079-4991, Vol. 10, no 5, article id 900Article in journal (Refereed)
    Abstract [en]

    The conservation of textiles is a challenge due to the often fast degradation that results from the acidity combined with a complex structure that requires remediation actions to be conducted at several length scales. Nanomaterials have lately been used for various purposes in the conservation of cultural heritage. The advantage with these materials is their high efficiency combined with a great control. Here, we provide an overview of the latest developments in terms of nanomaterials-based alternatives, namely inorganic nanoparticles and nanocellulose, to conventional methods for the strengthening and deacidification of cellulose-based materials. Then, using the case of iron-tannate dyed cotton, we show that conservation can only be addressed if the mechanical strengthening is preceded by a deacidification step. We used CaCO3 nanoparticles to neutralize the acidity, while the stabilisation was addressed by a combination of nanocellulose, and silica nanoparticles, to truly tackle the complexity of the hierarchical nature of cotton textiles. Silica nanoparticles enabled strengthening at the fibre scale by covering the fibre surface, while the nanocellulose acted at bigger length scales. The evaluation of the applied treatments, before and after an accelerated ageing, was assessed by tensile testing, the fibre structure by SEM and the apparent colour changes by colourimetric measurements.

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  • 13.
    Schavkan, Alexander
    et al.
    PTB Physikalisch–Technische Bundesanstalt, Germany.
    Gollwitzer, Christian
    PTB Physikalisch–Technische Bundesanstalt, Germany.
    Garcia-Diez, Raul
    PTB Physikalisch–Technische Bundesanstalt, Germany.
    Krumrey, Michael
    PTB Physikalisch–Technische Bundesanstalt, Germany.
    Minelli, Caterina
    NPL National Physical Laboratory, UK.
    Bartczak, Dorota
    LGC Ld, UK.
    Cuello-Nuñez, Susana
    LGC Ld, UK.
    Goenaga-Infante, Heidi
    LGC Ld, UK.
    Rissler, Jenny
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation.
    Sjöström, Eva
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation.
    Baur, Guillamue
    METAS Federal Institute of Metrology, Switzerland.
    Vasilatou, Konstantina
    METAS Federal Institute of Metrology, Switzerland.
    Shard, Alexander
    NPL National Physical Laboratory, UK.
    Number concentration of gold nanoparticles in suspension: SAXS and spICPMS as traceable methods compared to laboratory methods2019In: Nanomaterials, E-ISSN 2079-4991, Vol. 9, no 4, article id 502Article in journal (Refereed)
    Abstract [en]

    The industrial exploitation of high value nanoparticles is in need of robust measurement methods to increase the control over product manufacturing and to implement quality assurance. InNanoPart, a European metrology project responded to these needs by developing methods for the measurement of particle size, concentration, agglomeration, surface chemistry and shell thickness. This paper illustrates the advancements this project produced for the traceable measurement of nanoparticle number concentration in liquids through small angle X-ray scattering (SAXS) and single particle inductively coupled plasma mass spectrometry (spICPMS). It also details the validation of a range of laboratory methods, including particle tracking analysis (PTA), dynamic light scattering (DLS), differential centrifugal sedimentation (DCS), ultraviolet visible spectroscopy (UV-vis) and electrospray-differential mobility analysis with a condensation particle counter (ES-DMA-CPC). We used a set of spherical gold nanoparticles with nominal diameters between 10 nm and 100 nm and discuss the results from the various techniques along with the associated uncertainty budgets.

  • 14.
    Sepehri, Sobhan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Andersson, Johanna
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Schaller, Vincent
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Grüttner, Cordula
    Micromod Partikeltechnologie GmbH, Germany.
    Stading, Mats
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Johansson, Christer
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Remote Sensing of the Nano-Rheological Properties of Soft Materials Using Magnetic Nanoparticles and Magnetic AC Susceptometry2023In: Nanomaterials, E-ISSN 2079-4991, Vol. 13, no 1, article id 67Article in journal (Refereed)
    Abstract [en]

    We have developed a nano-rheological characterization tool to extract the frequency- and scale-dependent rheological properties of soft materials during oral processing. Taking advantage of AC susceptometry, the dynamic magnetization of magnetic nanoparticles blended in the matrix material is measured. The magnetic AC susceptibility spectra of the particles are affected by the viscosity and mechanical modulus of the matrix material and provide the rheological properties of the matrix. Commercially available iron-oxide magnetic nanoparticles with 80 and 100 nm particle sizes are used as tracers in the frequency range of 1 Hz–10 kHz. The AC susceptibility is measured using two differentially connected coils, and the effects of the sample temperature and distance with respect to the detection coils are investigated. The developed measurement setup shows the feasibility of remote nano-rheological measurements up to 2 cm from the coil system, which can be used to, e.g., monitor the texture of matrix materials during oral processing.

  • 15.
    Singh, Shikha
    et al.
    Luleå University of Technology, Sweden; Universitat Politècnica de Catalunya Barcelona Tech, Spain.
    Patel, Mitul
    Luleå University of Technology, Sweden.
    Geng, Shiyu
    Luleå University of Technology, Sweden.
    Teleman, Anita
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Herrera, Natalia
    Luleå University of Technology, Sweden.
    Schwendemann, Daniel
    Luleå University of Technology, Sweden; OST Eastern Switzerland University of Applied Sciences, Switzerland.
    Maspoch, Maria
    Universitat Politècnica de Catalunya Barcelona Tech, Spain.
    Oksman, Kristina
    Luleå University of Technology, Sweden;University of Toronto, Canada.
    Orientation of polylactic acid–chitin nanocomposite films via combined calendering and uniaxial drawing: Effect on structure, mechanical, and thermal properties2021In: Nanomaterials, E-ISSN 2079-4991, Vol. 11, no 12, article id 3308Article in journal (Refereed)
    Abstract [en]

    The orientation of polymer composites is one way to increase the mechanical properties of the material in a desired direction. In this study, the aim was to orient chitin nanocrystal (ChNC)-reinforced poly(lactic acid) (PLA) nanocomposites by combining two techniques: calendering and solid-state drawing. The effect of orientation on thermal properties, crystallinity, degree of orientation, mechanical properties and microstructure was studied. The orientation affected the thermal and structural behavior of the nanocomposites. The degree of crystallinity increased from 8% for the isotropic compression-molded films to 53% for the nanocomposites drawn with the highest draw ratio. The wide-angle X-ray scattering results confirmed an orientation factor of 0.9 for the solid-state drawn nanocomposites. The mechanical properties of the oriented nanocomposite films were significantly improved by the orientation, and the pre-orientation achieved by film calendering showed very positive effects on solid-state drawn nanocomposites: The highest mechanical properties were achieved for pre-oriented nanocomposites. The stiffness increased from 2.3 to 4 GPa, the strength from 37 to 170 MPa, the elongation at break from 3 to 75%, and the work of fracture from 1 to 96 MJ/m3. This study demonstrates that the pre-orientation has positive effect on the orientation of the nanocomposites structure and that it is an extremely efficient means to produce films with high strength and toughness. © 2021 by the authors. 

  • 16.
    Ul Hassan Alvi, Naveed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    Mulla, Yusuf
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden. Digital Cellulose Center, Sweden.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. Digital Cellulose Center, Sweden.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware. Digital Cellulose Center, Sweden.
    The Fast and One-Step Growth of ZnO Nanorods on Cellulose Nanofibers for Highly Sensitive Photosensors2023In: Nanomaterials, E-ISSN 2079-4991, Vol. 13, no 18, article id 2611Article in journal (Refereed)
    Abstract [en]

    Cellulose is the most abundant organic material on our planet which has a key role in our daily life (e.g., paper, packaging). In recent years, the need for replacing fossil-based materials has expanded the application of cellulose and cellulose derivatives including into electronics and sensing. The combination of nanostructures with cellulose nanofibers (CNFs) is expected to create new opportunities for the development of innovative electronic devices. In this paper, we report on a single-step process for the low temperature (<100 °C), environmentally friendly, and fully scalable CNF-templated highly dense growth of zinc oxide (ZnO) nanorods (NRs). More specifically, the effect of the degree of substitution of the CNF (enzymatic CNFs and carboxymethylated CNFs with two different substitution levels) on the ZnO growth and the application of the developed ZnO NRs/CNF nanocomposites in the development of UV sensors is reported herein. The results of this investigation show that the growth and nature of ZnO NRs are strongly dependent on the charge of the CNFs; high charge promotes nanorod growth whereas with low charge, ZnO isotropic microstructures are created that are not attached to the CNFs. Devices manufactured via screen printing/drop-casting of the ZnO NRs/CNF nanocomposites demonstrate a good photo-sensing response with a very stable UV-induced photocurrent of 25.84 µA. This also exhibits excellent long-term stability with fast ON/OFF switching performance under the irradiance of a UV lamp (15 W). 

  • 17.
    Ul Hassan Alvi, Naveed
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sandberg, Mats
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Sustainable and Low-Cost Electrodes for Photocatalytic Fuel Cells2024In: Nanomaterials, E-ISSN 2079-4991, Vol. 14, no 7, article id 636Article in journal (Refereed)
    Abstract [en]

    Water pollutants harm ecosystems and degrade water quality. At the same time, many pollutants carry potentially valuable chemical energy, measured by chemical oxygen demand (COD). This study highlights the potential for energy harvesting during remediation using photocatalytic fuel cells (PCFCs), stressing the importance of economically viable and sustainable materials. To achieve this, this research explores alternatives to platinum cathodes in photocathodes and aims to develop durable, cost-effective photoanode materials. Here, zinc oxide nanorods of high density are fabricated on carbon fiber surfaces using a low-temperature aqueous chemical growth method that is simple, cost-efficient, and readily scalable. Alternatives to the Pt cathodes frequently used in PCFC research are explored in comparison with screen-printed PEDOT:PSS cathodes. The fabricated ZnO/carbon anode (1.5 × 2 cm2) is used to remove the model pollutant used here and salicylic acid from water (30 mL, 70 μM) is placed under simulated sunlight (0.225 Sun). It was observed that salicylic acid was degraded by 23 ±0.46% at open voltage (OV) and 43.2 ± 0.86% at 1 V with Pt as the counter electrode, degradation was 18.5 ± 0.37% at open voltage (OV) and 44.1 ± 0.88% at 1 V, while PEDOT:PSS was used as the counter electrode over 120 min. This shows that the PEDOT:PSS exhibits an excellent performance with the full potential to provide low-environmental-impact electrodes for PCFCs. 

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  • 18.
    Völtz, Luísa Rosenstock
    et al.
    Luleå University of Technology, Sweden.
    Geng, Shiyu
    Luleå University of Technology, Sweden.
    Teleman, Anita
    RISE Research Institutes of Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Sweden; University of Toronto, Canada.
    Influence of Dispersion and Orientation on Polyamide-6 Cellulose Nanocomposites Manufactured through Liquid-Assisted Extrusion2022In: Nanomaterials, E-ISSN 2079-4991, Vol. 12, no 5, article id 818Article in journal (Refereed)
    Abstract [en]

    In this study, the possibility of adding nanocellulose and its dispersion to polyamide 6 (PA6), a polymer with a high melting temperature, is investigated using melt extrusion. The main challenges of the extrusion of these materials are achieving a homogeneous dispersion and avoiding the thermal degradation of nanocellulose. These challenges are overcome by using an aqueous suspension of never-dried nanocellulose, which is pumped into the molten polymer without any chemical modification or drying. Furthermore, polyethylene glycol is tested as a dispersant for nanocellulose. The dispersion, thermal degradation, and mechanical and viscoelastic properties of the nanocomposites are studied. The results show that the dispersant has a positive impact on the dispersion of nanocellulose and that the liquid-assisted melt compounding does not cause the degradation of nanocellulose. The addition of only 0.5 wt.% nanocellulose increases the stiffness of the neat polyamide 6 from 2 to 2.3 GPa and shifts the tan δ peak toward higher temperatures, indicating an interaction between PA6 and nanocellulose. The addition of the dispersant decreases the strength and modulus but has a significant effect on the elongation and toughness. To further enhance the mechanical properties of the nanocomposites, solid-state drawing is used to create an oriented structure in the polymer and nanocomposites. The orientation greatly improves its mechanical properties, and the oriented nanocomposite with polyethylene glycol as dispersant exhibits the best alignment and properties: with orientation, the strength increases from 52 to 221 MPa, modulus from 1.4 to 2.8 GPa, and toughness 30 to 33 MJ m<sup>-3</sup> in a draw ratio of 2.5. This study shows that nanocellulose can be added to PA6 by liquid-assisted extrusion with good dispersion and without degradation and that the orientation of the structure is a highly-effective method for producing thermoplastic nanocomposites with excellent mechanical properties.

  • 19.
    Yager, Tom
    et al.
    University of Latvia, Latvia.
    Chikvaidze, George
    University of Latvia, Latvia.
    Wang, Qin
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Fu, Ying
    Halmstad University, Sweden.
    Graphene Hybrid Metasurfaces for Mid-Infrared Molecular Sensors2023In: Nanomaterials, E-ISSN 2079-4991, Vol. 13, no 14, article id 2113Article in journal (Refereed)
    Abstract [en]

    We integrated graphene with asymmetric metal metasurfaces and optimised the geometry dependent photoresponse towards optoelectronic molecular sensor devices. Through careful tuning and characterisation, combining finite-difference time-domain simulations, electron-beam lithography-based nanofabrication, and micro-Fourier transform infrared spectroscopy, we achieved precise control over the mid-infrared peak response wavelengths, transmittance, and reflectance. Our methods enabled simple, reproducible and targeted mid-infrared molecular sensing over a wide range of geometrical parameters. With ultimate minimization potential down to atomic thicknesses and a diverse range of complimentary nanomaterial combinations, we anticipate a high impact potential of these technologies for environmental monitoring, threat detection, and point of care diagnostics. 

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