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  • 1.
    Abitbol, Tiffany
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Ahniyaz, Anwar
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Alvarez-Asencio, Ruben
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Swerin, Agne
    KTH Royal Institute of Technology, Sweden.
    Nanocellulose-Based Hybrid Materials for UV Blocking and Mechanically Robust Barriers2020Inngår i: ACS Applied Bio Materials, E-ISSN 2576-6422, Vol. 3, nr 4, s. 2245-2254Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocellulose (NC)-based hybrid coatings and films containing CeO2 and SiO2 nanoparticles (NPs) to impart UV screening and hardness properties, respectively, were prepared by solvent casting. The NC film-forming component (75 wt % of the overall solids) was composed entirely of cellulose nanocrystals (CNCs) or of CNCs combined with cellulose nanofibrils (CNFs). Zeta potential measurements indicated that the four NP types (CNC, CNF, CeO2, and SiO2) were stably dispersed in water and negatively charged at pH values between 6 and 9. The combination of NPs within this pH range ensured uniform formulations and homogeneous coatings and films, which blocked UV light, the extent of which depended on film thickness and CeO2 NP content, while maintaining good transparency in the visible spectrum (∼80%). The addition of a low amount of CNFs (1%) reduced the film hardness, but this effect was compensated by the addition of SiO2 NPs. Chiral nematic self-assembly was observed in the mixed NC film; however, this ordering was disrupted by the addition of the oxide NPs. The roughness of the hybrid coatings was reduced by the inclusion of oxide NPs into the NC matrix perhaps because the spherical oxide NPs were able to pack into the spaces between cellulose fibrils. We envision these hybrid coatings and films in barrier applications, photovoltaics, cosmetic formulations, such as sunscreens, and for the care and maintenance of wood and glass surfaces, or other surfaces that require a smooth, hard, and transparent finish and protection from UV damage.

  • 2.
    Andersson Ersman, Peter
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Freitag, Kathrin
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Nilsson, Marie
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Åhlin, Jessica
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Nordgren, Niklas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Nevo, Yuval
    Melodea Ltd, Israel.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Electrochromic Displays Screen Printed on Transparent Nanocellulose-Based Substrates2023Inngår i: Advanced Photonics Research, ISSN 2699-9293, artikkel-id 2200012Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Manufacturing of electronic devices via printing techniques is often considered to be an environmentally friendly approach, partially due to the efficient utilization of materials. Traditionally, printed electronic components (e.g., sensors, transistors, and displays) are relying on flexible substrates based on plastic materials; this is especially true in electronic display applications where, most of the times, a transparent carrier is required in order to enable presentation of the display content. However, plastic-based substrates are often ruled out in end user scenarios striving toward sustainability. Paper substrates based on ordinary cellulose fibers can potentially replace plastic substrates, but the opaqueness limits the range of applications where they can be used. Herein, electrochromic displays that are manufactured, via screen printing, directly on state-of-the-art fully transparent substrates based on nanocellulose are presented. Several different nanocellulose-based substrates, based on either nanofibrillated or nanocrystalline cellulose, are manufactured and evaluated as substrates for the manufacturing of electrochromic displays, and the optical and electrical switching performances of the resulting display devices are reported and compared. The reported devices do not require the use of metals and/or transparent conductive oxides, thereby providing a sustainable all-printed electrochromic display technology.

  • 3.
    Aulin, Christian
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi.
    Fall, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi.
    Abitbol, Tíffany
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi.
    Nordgren, Nklas
    RISE - Research Institutes of Sweden (2017-2019), Biovetenskap och material, Yta, process och formulering.
    Aivarez-Asencio, Ruben
    RISE - Research Institutes of Sweden (2017-2019), Biovetenskap och material, Yta, process och formulering.
    Designing flexible, smooth, highly transparent and hazy cnf films2019Inngår i: International Conference on Nanotechnology for Renewable Materials 2019, TAPPI Press , 2019, s. 435-445Konferansepaper (Fagfellevurdert)
  • 4.
    Benselfelt, T.
    et al.
    KTH Royal Institute of Technology, Sweden; Nanyang Technological University, Singapore.
    Kummer, N.
    Empa Swiss Federal Laboratories for Materials Science and Technology, Switzerland; ETH Zürich, Switzerland.
    Nordenström, M.
    KTH Royal Institute of Technology, Sweden.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Nyström, G.
    Empa Swiss Federal Laboratories for Materials Science and Technology, Switzerland; ETH Zürich, Switzerland.
    Wågberg, L.
    KTH Royal Institute of Technology, Sweden.
    The Colloidal Properties of Nanocellulose2023Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 16, nr 8, s. e202201955-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocelluloses are anisotropic nanoparticles of semicrystalline assemblies of glucan polymers. They have great potential as renewable building blocks in the materials platform of a more sustainable society. As a result, the research on nanocellulose has grown exponentially over the last decades. To fully utilize the properties of nanocelluloses, a fundamental understanding of their colloidal behavior is necessary. As elongated particles with dimensions in a critical nanosize range, their colloidal properties are complex, with several behaviors not covered by classical theories. In this comprehensive Review, we describe the most prominent colloidal behaviors of nanocellulose by combining experimental data and theoretical descriptions. We discuss the preparation and characterization of nanocellulose dispersions, how they form networks at low concentrations, how classical theories cannot describe their behavior, and how they interact with other colloids. We then show examples of how scientists can use this fundamental knowledge to control the assembly of nanocellulose into new materials with exceptional properties. We hope aspiring and established researchers will use this Review as a guide. © 2023 The Authors. 

  • 5.
    Brooke, Robert
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Borras, M.
    LEITAT Technological Center, Spain.
    Belaineh Yilma, Dagmawi
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Martinez-Crespiera, S.
    LEITAT Technological Center, Spain.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors2021Inngår i: Flexible and Printed Electronics, ISSN 2058-8585, Vol. 6, nr 4, artikkel-id 045011Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conventional electronics have been highlighted as a very unsustainable technology; hazardous wastes are produced both during their manufacturing but also, due to their limited recyclability, during their end of life cycle (e.g. disposal in landfill). In recent years additive manufacturing processes (i.e. screen printing) have attracted significant interest as a more sustainable approach to electronic manufacturing (printed electronics). Despite the field of printed electronics addressing some of the issues related to the manufacturing of electronics, many components and inks are still considered hazardous to the environment and are difficult to recycle. Here we present the development of a low environmental impact carbon ink based on a non-hazardous solvent and a cellulosic matrix (nanocellulose) and its implementation in electrochromic displays (ECDs) and supercapacitors. As part of the reported work, a different protocol for mixing carbon and cellulose nanofibrils (rotation mixing and high shear force mixing), nanocellulose of different grades and different carbon: nanocellulose ratios were investigated and optimized. The rheology profiles of the different inks showed good shear thinning properties, demonstrating their suitability for screen-printing technology. The printability of the developed inks was excellent and in line with those of reference commercial carbon inks. Despite the lower electrical conductivity (400 S m-1 for the developed carbon ink compared to 1000 S m-1 for the commercial inks), which may be explained by their difference in composition (carbon content, density and carbon derived nature) compared to the commercial carbon, the developed ink functioned adequately as the counter electrode in all screen-printed ECDs and even allowed for improved supercapacitors compared to those utilizing commercial carbon inks. In this sense, the supercapacitors incorporating the developed carbon ink in the current collector layer had an average capacitance = 97.4 mF cm-2 compared to the commercial carbon ink average capacitance = 61.6 mF cm-2. The ink development reported herein provides a step towards more sustainable printed green electronics. © 2021 The Author(s).

  • 6. Carlsson, L.
    et al.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Chaduc, I.
    Wågberg, L.
    Charleux, B.
    Malmström, E.
    D’Agosto, F.
    Lansalot, M.
    Carlmark, A.
    Modification of cellulose model surfaces by cationic polymer latexes prepared by RAFT-mediated surfactant-free emulsion polymerization2014Inngår i: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 5, nr 20, s. 6076-6086Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the successful surface modification of a model cellulose substrate by the preparation and subsequent physical adsorption of cationic polymer latexes. The first part of the work introduces novel charged polymer nanoparticles constituted of amphiphilic block copolymers based on cationic poly(N,N-dimethylaminoethyl methacrylate-co-methacrylic acid) (P(DMAEMA-co-MAA)) as the hydrophilic segment, and poly(methyl methacrylate) (PMMA) as the hydrophobic segment. First, RAFT polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) in water was performed at pH 7, below its pKa. The simultaneous hydrolysis of DMAEMA led to the formation of a statistical copolymer incorporating mainly protonated DMAEMA units and some deprotonated methacrylic acid units at pH 7. The following step was the RAFT-mediated surfactant-free emulsion polymerization of methyl methacrylate (MMA) using P(DMAEMA-co-MAA) as a hydrophilic macromolecular RAFT agent. During the synthesis, the formed amphiphilic block copolymers self-assembled into cationic latex nanoparticles by polymerization-induced self-assembly (PISA). The nanoparticles were found to increase in size with increasing molar mass of the hydrophobic block. The cationic latexes were subsequently adsorbed to cellulose model surfaces in a quartz crystal microbalance equipment with dissipation (QCM-D). The adsorbed amount, in mg m-2, increased with increasing size of the nanoparticles. This approach allows for physical surface modification of cellulose, utilizing a water suspension of particles for which both the surface chemistry and the surface structure can be altered in a well-defined way. 

  • 7.
    Edberg, Jesper
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Boda, Ulrika
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. Linköping University, Sweden.
    Mulla, Yusuf
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Pantzare, Sandra
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Strandberg, Jan
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Economou, Konstantin
    Linköping University, Sweden.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Armgarth, Astrid
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    A Paper‐Based Triboelectric Touch Interface: Toward Fully Green and Recyclable Internet of Things2023Inngår i: Advanced Sensor Research, Vol. 2, nr 1, artikkel-id 2200015Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transition to a sustainable society is driving the development of green electronic solutions designed to have a minimal environmental impact. One promising route to achieve this goal is to construct electronics from biobased materials like cellulose, which is carbon neutral, non‐toxic, and recyclable. This is especially true for internet‐of‐things devices, which are rapidly growing in number and are becoming embedded in every aspect of our lives. Here, paper‐based sensor circuits are demonstrated, which use triboelectric pressure sensors to help elderly people communicate with the digital world using an interface in the form of an electronic “book”, which is more intuitive to them. The sensors are manufactured by screen printing onto flexible paper substrates, using in‐house developed cellulose‐based inks with non‐hazardous solvents. The triboelectric sensor signal, generated by the contact between a finger and chemically modified cellulose, can reach several volts, which can be registered by a portable microcontroller card and transmitted by Bluetooth to any device with an internet connection. Apart from the microcontroller (which can be easily removed), the whole system can be recycled at the end of life. A triboelectric touch interface, manufactured using printed electronics on flexible paper substrates, using cellulose‐based functional inks is demonstrated. These metal‐free green electronics circuits are implemented in an “electronic book” demonstrator, equipped with wireless communication that can control remote devices, as a step toward sustainable and recyclable internet‐of‐things devices.

  • 8.
    Edberg, Jesper
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Brooke, Robert
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Hosseinaei, Omid
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Wijeratne, Kosala
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Sandberg, Mats
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Laser-induced graphitization of a forest-based ink for use in flexible and printed electronics2020Inngår i: npj Flexible Electron., ISSN 2397-4621, Vol. 4, artikkel-id 17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Laser-induced graphitization (LIG) is a method of converting a carbon-rich precursor into a highly conductive graphite-like carbon by laser scribing. This method has shown great promise as a versatile and low-cost patterning technique. Here we show for the first time how an ink based on cellulose and lignin can be patterned using screen printing followed by laser graphitization. Screen printing is one of the most commonly used manufacturing techniques of printed electronics, making this approach compatible with existing processing of various devices. The use of forest-based materials opens the possibility of producing green and sustainable electronics. Pre-patterning of the ink enables carbon patterns without residual precursor between the patterns. We investigated the effect of the ink composition, laser parameters, and additives on the conductivity and structure of the resulting carbon and could achieve low sheet resistance of 3.8 Ω sq-1 and a high degree of graphitization. We demonstrated that the process is compatible with printed electronics and finally manufactured a humidity sensor which uses lignin as the sensing layer and graphitized lignin as the electrodes.

  • 9.
    Engquist, Isak
    et al.
    Linköping University, Sweden.
    Berggren, Magnus
    Linköping University, Sweden.
    Isacsson, Patrik
    Linköping University, Sweden.
    Wang, Xin
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Massa, papper och förpackningar.
    Mengistie, Desalegn Alemu
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Calvie, Emilie
    Ahlstrom-Munksjo Research Center, France.
    Granberg, Hjalmar
    Linköping University, Sweden.
    Gustafsson, Göran
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Highly conducting nanographite-filled paper fabricated via standard papermaking techniques2020Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, nr 43, s. 48828-48835Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eco-friendly and cost-effective materials and processes to manufacture functional substrates are crucial to further advance the area of printed electronics. One potential key component in the printed electronics platform is an electrically functionalized paper, produced by simply mixing common cellulosic pulp fibers with high-performance electroactive materials. Herein, an electronic paper including nanographite has been prepared using a standardized and scalable papermaking technique. No retention aid was needed to achieve a conducting nanographite loading as high as 50 wt %. The spontaneous retention that provides the integrity and stability of the nanographite paper, likely originates partially from an observed water-stable adhesion of nanographite flakes onto the fiber surfaces. The resulting paper exhibits excellent electrical characteristics, such as an in-plane conductivity of 107 S/cm and an areal capacitance of 9.2 mF/cm2, and was explored as the back-electrode in printed electrochromic displays.

  • 10.
    Fall, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi.
    Nanocellulose and graphene: promising hybrid materials2018Inngår i: Recent advances in cellulose nanotechnology research: production, characterization and applications, Trondheim: RISE PFI , 2018Konferansepaper (Fagfellevurdert)
  • 11.
    Fall, Andreas
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Hagel, Farnaz
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Malti, Abdellah
    KTH Royal Institute of Technology, Sweden.
    Larsson, Per A.
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden; Wallenberg Wood Science Center, Sweden; Digital Cellulose Center, Sweden.
    Granberg, Hjalmar
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Håkansson, Karl MO
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Spinning of Stiff and Conductive Filaments from Cellulose Nanofibrils and PEDOT:PSS Nanocomplexes2022Inngår i: ACS Applied Polymer Materials, ISSN 2637-6105, Vol. 4, nr 6, s. 4119-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Research in smart textiles is growing due to the increased demand from the healthcare sector and people's urge to keep track of and analyze the signals and metrics from their bodies. Electrically conductive filaments are the most fundamental material for smart textiles. These filaments can be imbued with functionalities and useful in fields like energy storage, sensing, and actuation. To be able to meet the requirements that the latter applications require, fabrication techniques must be developed to provide better processability and sustainability in a cost-effective manner. Here, a mixture of a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), and biobased cellulose nanofibrils (CNFs) was used to spin filaments utilizing a water-based process. These filaments show electrical conductivities up to 150 S/cm and tensile stiffness of 20 GPa. Interestingly, the PEDOT aligned to a similar degree as the CNFs during the spinning process without a drawing step, which is hypothesized to be caused by the attachment of PEDOT on the CNFs. Lastly, the filaments were tested in an organic electrochemical transistor (OECT) configuration, which resulted in a working device with an on/off ratio approaching 1500. Furthermore, the OECT exhibited stable behavior when changing temperature (20-80 °C) and relative humidity (40-80%). This aqueous spinning method, resulting in filaments with robust electronic properties in different temperature and humidity environments, show greats promise for future innovative smart textiles.

  • 12.
    Fall, Andreas
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Henriksson, Marielle
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Karppinen, A.
    Borregaard, Norway.
    Opstad, A.
    Borregaard, Norway.
    Heggset, Ellinor B
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    The effect of ionic strength and pH on the dewatering rate of cellulose nanofibril dispersions2022Inngår i: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 29, nr 14, s. 7649-7662Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanofibrils, CNFs, show great potential in many application areas. One main aspect limiting the industrial use is the slow and energy demanding dewatering of CNF suspensions. Here we investigate the dewatering with a piston press process. Three different CNF grades were dewatered to solid contents between approx. 20 and 30%. The CNF grades varied in charge density (30, 106 and 604 µmol/g) and fibrillation degree. The chemical conditions were varied by changing salt concentration (NaCl) and pH and the dewatering rates were compared before and after these changes. For the original suspensions, a higher charge provides slower dewatering with the substantially slowest dewatering for the highest charged CNFs. However, by changing the conditions it dewatered as fast as the two lower charged CNFs, even though the salt/acid additions also improved the dewatering rate for these two CNFs. Finally, by tuning the conditions, fast dewatering could be obtained with only minor effect on film properties (strength and oxygen barrier) produced from redispersed dispersion. However, dewatering gives some reduction in viscosity of the redispersed dispersions. This may be a disadvantage if the CNF application is as e.g. rheology modifier or emulsion stabilizer. Graphical abstract: [Figure not available: see fulltext.].

  • 13.
    Fall, Andreas
    et al.
    KTH Royal Institute of Technology, Sweden.
    Lindström, S. B.
    Sprakel, J.
    Wågberg, L.
    A physical cross-linking process of cellulose nanofibril gels with shear-controlled fibril orientation2013Inngår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 9, nr 6, s. 1852-1863Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanofibrils constitute the smallest fibrous components of wood, with a width of approximately 4 nm and a length in the micrometer range. They consist of aligned linear cellulose chains with crystallinity exceeding 60%, rendering stiff, high-aspect-ratio rods. These properties are advantageous in the reinforcement components of composites. Cross-linked networks of fibrils can be used as templates into which a polymer enters. In the semi-concentrated regime (i.e. slightly above the overlap concentration), carboxy methylated fibrils dispersed in water have been physically cross-linked to form a volume-spanning network (a gel) by reducing the pH or adding salt, which diminishes the electrostatic repulsion between fibrils. By applying shear during or after this gelation process, we can orient the fibrils in a preferred direction within the gel, for the purpose of fully utilizing the high stiffness and strength of the fibrils as reinforcement components. Using these gels as templates enables precise control of the spatial distribution and orientation of the dispersed phase of the composites, optimizing the potentially very large reinforcement capacity of the nanofibrils. 

  • 14.
    Fall, Andreas
    et al.
    KTH Royal Institute of Technology, Sweden.
    Lindström, S. B.
    Sundman, O.
    Ödberg, L.
    Wågberg, L.
    Colloidal stability of aqueous nanofibrillated cellulose dispersions2011Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, nr 18, s. 11332-11338Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanofibrils constitute an attractive raw material for carbon-neutral, biodegradable, nanostructured materials. Aqueous suspensions of these nanofibrils are stabilized by electrostatic repulsion arising from deprotonated carboxyl groups at the fibril surface. In the present work, a new model is developed for predicting colloidal stability by considering deprotonation and electrostatic screening. This model predicts the fibril-fibril interaction potential at a given pH in a given ionic strength environment. Experiments support the model predictions that aggregation is induced by decreasing the pH, thus reducing the surface charge, or by increasing the salt concentration. It is shown that the primary mechanism for aggregation upon the addition of salt is the surface charge reduction through specific interactions of counterions with the deprotonated carboxyl groups, and the screening effect of the salt is of secondary importance. 

  • 15.
    Fall, Andreas
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Zhao, Wei
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Blademo, Åsa
    RISE Research Institutes of Sweden.
    Bodelsson, Jens
    RISE Research Institutes of Sweden.
    Sugunan, Abhilash
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Nordgren, Niklas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden.
    Carlmark, Anna
    RISE Research Institutes of Sweden.
    Gillgren, Thomas
    RISE Research Institutes of Sweden.
    Hybrid Materials of Nanocellulose and Graphene2019Inngår i: International Conference on Nanotechnology for Renewable Materials 2019, TAPPI Press , 2019, Vol. 2, s. 1069-1080Konferansepaper (Fagfellevurdert)
  • 16.
    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, Bioekonomi och hälsa, Material- och ytdesign.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    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 Supercapacitors2022Inngår i: Nanomaterials, E-ISSN 2079-4991, Vol. 12, nr 2, artikkel-id 273Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 17. Gordeyeva, K. S.
    et al.
    Fall, Andreas
    Stockholm University, Sweden.
    Hall, S.
    Wicklein, B.
    Bergström, L.
    Stabilizing nanocellulose-nonionic surfactant composite foams by delayed Ca-induced gelation2016Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 472, s. 44-51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aggregation of dispersed rod-like particles like nanocellulose can improve the strength and rigidity of percolated networks but may also have a detrimental effect on the foamability. However, it should be possible to improve the strength of nanocellulose foams by multivalent ion-induced aggregation if the aggregation occurs after the foam has been formed. Lightweight and highly porous foams based on TEMPO-mediated oxidized cellulose nanofibrils (CNF) were formulated with the addition of a non-ionic surfactant, pluronic P123, and CaCO3 nanoparticles. Foam volume measurements show that addition of the non-ionic surfactant generates wet CNF/P123 foams with a high foamability. Foam bubble size studies show that delayed Ca-induced aggregation of CNF by gluconic acid-triggered dissolution of the CaCO3 nanoparticles significantly improves the long-term stability of the wet composite foams. Drying the Ca-reinforced foam at 60 °C results in a moderate shrinkage and electron microscopy and X-ray tomography studies show that the pores became slightly oblate after drying but the overall microstructure and pore/foam bubble size distribution is preserved after drying. The elastic modulus (0.9-1.4 MPa) of Ca-reinforced composite foams with a density of 9-15 kg/m3 is significantly higher than commercially available polyurethane foams used for thermal insulation.

  • 18.
    Granberg, Hjalmar
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Papperstillverkning och förpackningar.
    Håkansson, Karl
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Papperstillverkning och förpackningar.
    Fall, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Papperstillverkning och förpackningar.
    Wågberg, Pia
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Papperstillverkning och förpackningar.
    Electroactive papers, films, filaments, aerogels and hydrogels to realize the future of bio-based electronics2019Inngår i: PaperCon 2019: Proceedings, TAPPI Press, 2019, artikkel-id PF4.1Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Research has been undertaken into the mixing of electroactive additives (EAA), for example, conducting polymers or particles, in five different cellulose structures and their further processing into electroactive papers and films. The cellulose structures considered included cellulose nanofibrils (CNF) hydrogels, CNG aerogels, CNF filaments, CNF films and cellulose papers. It has been demonstrated that the cellulose structure in combination with the electroactive polymer or particle, could be used to tailor numerous different properties. The cellulose could provide properties that support structural integrity, processability, ionic conductivity, shapeability and a large inner capacitive surface. The highly porous aerogel particles could be shaped using three-dimensional printed templates prior to freezing. The particles could be filled either with active material from the start before freeze-linking or filled with active material afterwards based on the layer by layer method. Electroactive paper could also be produced by adding the active component directly as a filler during papermaking, by adding CNF spun EA filaments cut into conveniently long staple fibres.

  • 19.
    Guccini, Valentina
    et al.
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Yu, Shun
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi. Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Agthe, Michael
    Stockholm University, Sweden; University of Hamburg, Germany.
    Gordeyeva, Korneliya S.
    Stockholm University, Sweden.
    Trushkina, Yulia
    Stockholm University, Sweden.
    Fall, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi. Stockholm University, Sweden.
    Schütz, Christina
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden; University of Luxembourg, Luxembourg.
    Salazar-Alvarez, German
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Inducing nematic ordering of cellulose nanofibers using osmotic dehydration2018Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, nr 48, s. 23157-23163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of nematically-ordered cellulose nanofiber (CNF) suspensions with an order parameter fmax ≈ 0.8 is studied by polarized optical microscopy, small-angle X-ray scattering (SAXS), and rheological measurements as a function of CNF concentration. The wide range of CNF concentrations, from 0.5 wt% to 4.9 wt%, is obtained using osmotic dehydration. The rheological measurements show a strong entangled network over all the concentration range whereas SAXS measurements indicate that at concentrations >1.05 wt% the CNF suspension crosses an isotropic-anisotropic transition that is accompanied by a dramatic increase of the optical birefringence. The resulting nanostructures are modelled as mass fractal structures that converge into co-existing nematically-ordered regions and network-like regions where the correlation distances decrease with concentration. The use of rapid, upscalable osmotic dehydration is an effective method to increase the concentration of CNF suspensions while partly circumventing the gel/glass formation. The facile formation of highly ordered fibers can result in materials with interesting macroscopic properties.

  • 20.
    Hamedi, M. M.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Hajian, A.
    KTH Royal Institute of Technology, Sweden.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Håkansson, K.
    KTH Royal Institute of Technology, Sweden.
    Salajkova, M.
    KTH Royal Institute of Technology, Sweden.
    Lundell, F.
    KTH Royal Institute of Technology, Sweden.
    Wågberg, L.
    KTH Royal Institute of Technology, Sweden.
    Berglund, L. A.
    KTH Royal Institute of Technology, Sweden.
    Highly conducting, strong nanocomposites based on nanocellulose-assisted aqueous dispersions of single-wall carbon nanotubes2014Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, nr 3, s. 2467-2476Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is challenging to obtain high-quality dispersions of single-wall nanotubes (SWNTs) in composite matrix materials, in order to reach the full potential of mechanical and electronic properties. The most widely used matrix materials are polymers, and the route to achieving high quality dispersions of SWNT is mainly chemical functionalization of the SWNT. This leads to increased cost, a loss of strength and lower conductivity. In addition full potential of colloidal self-assembly cannot be fully exploited in a polymer matrix. This may limit the possibilities for assembly of highly ordered structural nanocomposites. Here we show that nanofibrillated cellulose (NFC) can act as an excellent aqueous dispersion agent for as-prepared SWNTs, making possible low-cost exfoliation and purification of SWNTs with dispersion limits exceeding 40 wt %. The NFC:SWNT dispersion may also offer a cheap and sustainable alternative for molecular self-assembly of advanced composites. We demonstrate semitransparent conductive films, aerogels and anisotropic microscale fibers with nanoscale composite structure. The NFC:SWNT nanopaper shows increased strength at 3 wt % SWNT, reaching a modulus of 13.3 GPa, and a strength of 307 MPa. The anisotropic microfiber composites have maximum conductivities above 200 S cm-1 and current densities reaching 1400 A cm-2

  • 21.
    Håkansson, Karl M.O.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Lundell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Yu, S.
    DESY, Germany.
    Krywka, Christina A.
    University of Kiel, Germany; Helmholtz-Zentrum Geesthacht, Germany.
    Roth, Stephan Volkher
    University of Kiel, Germany.
    Santoro, Gonzalo
    DESY, Germany.
    Kvick, Mathias
    KTH Royal Institute of Technology, Sweden.
    Prahl Wittberg, Lisa
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars Göran
    KTH Royal Institute of Technology, Sweden.
    Söderberg, L. Daniel
    RISE., Innventia. KTH Royal Institute of Technology, Sweden.
    Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments2014Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 5, artikkel-id 4018Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanofibrils can be obtained from trees and have considerable potential as a building block for biobased materials. In order to achieve good properties of these materials, the nanostructure must be controlled. Here we present a process combining hydrodynamic alignment with a dispersion-gel transition that produces homogeneous and smooth filaments from a low-concentration dispersion of cellulose nanofibrils in water. The preferential fibril orientation along the filament direction can be controlled by the process parameters. The specific ultimate strength is considerably higher than previously reported filaments made of cellulose nanofibrils. The strength is even in line with the strongest cellulose pulp fibres extracted from wood with the same degree of fibril alignment. Successful nanoscale alignment before gelation demands a proper separation of the timescales involved. Somewhat surprisingly, the device must not be too small if this is to be achieved.

  • 22.
    Isacsson, Patrik
    et al.
    Linkoping University, Sweden.
    Jain, Karishma
    KTH Royal Institute of Technology, Sweden.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Chauve, Valerie
    Ahlstrom-Munksjö Research Center, France.
    Hajian, Alireza
    KTH Royal Institute of Technology, Sweden.
    Granberg, Hjalmar
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Boiron, Lucie
    Ahlstrom-Munksjö Research Center, France.
    Berggren, Magnus
    Linköping University, Sweden.
    Håkansson, Karl
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Edberg, Jesper
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Engquist, Isak
    Linköping University, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Production of energy-storage paper electrodes using a pilot-scale paper machine2022Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 10, nr 40, s. 21579-21589Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The global efforts in electrifying our society drive the demand for low-cost and sustainable energy storage solutions. In the present work, a novel material concept was investigated to enable fabrication of several 10 meter-long rolls of supercapacitor paper electrodes on a pilot-scale paper machine. The material concept was based on cationized, cellulose-rich wood-derived fibres, conducting polymer PEDOT:PSS, and activated carbon filler particles. Cationic fibres saturated with anionic PEDOT:PSS provide a conducting scaffold hosting the activated carbon, which functions as the active charge-storage material. The response from further additives was systematically investigated for several critical paper properties. Cellulose nanofibrils were found to improve mechanical properties, while carbon black enhanced both the conductivity and the storage capacity of the activated carbon, reaching a specific capacitance of 67 F g−1. This pilot trial shows that “classical” papermaking methods are fit for the purpose and provides valuable insights on how to further advance bio-based energy storage solutions for large-scale applications.

  • 23.
    Liu, Yingxin
    et al.
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Agthe, Michael
    Stockholm University, Sweden; University Of Hamburg, Germany.
    Salajková, Michaela
    University of Oslo, Norway.
    Gordeyeva, Korneliya S.
    Stockholm University, Sweden.
    Guccini, Valentina
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign. Stockholm University, Sweden.
    Salazar-Alvarez, German
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Schütz, Christina
    Stockholm University, Sweden; Wallenberg Wood Science Center, Sweden.
    Bergström, Lennart Magnus
    Stockholm University, Sweden.
    Assembly of cellulose nanocrystals in a levitating drop probed by time-resolved small angle X-ray scattering2018Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, nr 38, s. 18113-18118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Assembly of bio-based nano-sized particles into complex architectures and morphologies is an area of fundamental interest and technical importance. We have investigated the assembly of sulfonated cellulose nanocrystals (CNC) dispersed in a shrinking levitating aqueous drop using time-resolved small angle X-ray scattering (SAXS). Analysis of the scaling of the particle separation distance (d) with particle concentration (c) was used to follow the transition of CNC dispersions from an isotropic state at 1-2 vol% to a compressed nematic state at particle concentrations above 30 vol%. Comparison with SAXS measurements on CNC dispersions at near equilibrium conditions shows that evaporation-induced assembly of CNC in large levitating drops is comparable to bulk systems. Colloidal states with d vs. c scalings intermediate between isotropic dispersions and unidirectional compression of the nematic structure could be related to the biphasic region and gelation of CNC. Nanoscale structural information of CNC assembly up to very high particle concentrations can help to fabricate nanocellulose-based materials by evaporative methods.

  • 24.
    Liu, Yingxin
    et al.
    Stockholm University, Sweden; KTH Royal Institute of Technology, Sweden.
    Stoeckel, Daniela
    Stockholm University, Sweden.
    Gordeyeva, Kornelya
    Stockholm University, Sweden.
    Agthe, Michael
    Stockholm University, Sweden.
    Schutz, Christina
    Stockholm University, Sweden.
    Fall, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi. Stockholm University, Sweden.
    Bergstrom, Lennart
    Stockholm University, Sweden.
    Nanoscale Assembly of Cellulose Nanocrystals during Drying and Redispersion2018Inngår i: ACS Macro Letters, E-ISSN 2161-1653, Vol. 7, nr 2, s. 172-177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have followed the structural evolution during evaporation-induced self-assembly of sulfonated cellulose nanocrystal (CNC) in the presence of H+ and Li+ counterions by small-angle X-ray scattering. Drying of CNC-H dispersions results in ordered films that could not be readily redispersed, while the CNC-Li films were disordered and prone to reswelling and redispersion. The scaling of the separation distance (d) between CNC particles and the particle concentration (c) shows that the CNC-H dispersions display a unidimensional contraction of the nematic structure (d alpha c(-1)) during drying, while the CNC-Li dispersions consolidate isotropically (d alpha c(-1/3)), which is characteristic for hydrogels with no preferential orientation. Temporal evolution of the structure factor and complementary dynamic light-scattering measurements show that CNC-Li is more aggregated than CNC-H during evaporation-induced assembly. Insights on the structural evolution during CNC assembly and redispersion can promote development of novel and optimized processing routes of nanocellulose-based materials.

  • 25.
    Martinez-Crespiera, Sandra
    et al.
    Leitat Technological Center, Spain.
    Pepió-Tàrrega, Belen
    Leitat Technological Center, Spain.
    González-Gil, Rosa
    Leitat Technological Center, Spain.
    Cecilia-Morillo, Francisci
    Leitat Technological Center, Spain.
    Palmer, Javier
    Leitat Technological Center, Spain.
    Escobar, Ana
    Leitat Technological Center, Spain.
    Beneitez-Álvarez, Sirio
    Leitat Technological Center, Spain.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioekonomi och hälsa.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa.
    Nevo, Yuval
    Melodea Ltd, Israel.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Tolin, Enrico
    IMST GmbH, Germany.
    Bahr, Achim
    IMST GmbH, Germany.
    Use of Nanocellulose to Produce Water-Based Conductive Inks with Ag NPs for Printed Electronics2022Inngår i: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 23, nr 6, artikkel-id 2946Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The need for more sustainable printed electronics has emerged in the past years. Due to this, the use of nanocellulose (NC) extracted from cellulose has recently been demonstrated to provide interesting materials such as functional inks and transparent flexible films due to its properties. Its high specific surface area together with the high content of reactive hydroxyl groups provide a highly tailorable surface chemistry with applications in ink formulations as a stabilizing, capping, binding and templating agent. Moreover, NC mechanical, physical and thermal properties (high strength, low porosity and high thermal stability, respectively) provide an excellent alternative for the currently used plastic films. In this work, we present a process for the production of water-based conductive inks that uses NC both as a template for silver nanoparticles (Ag NPs) formation and as an ink additive for ink formulation. The new inks present an electrical conductivity up to 2 × 106 S/m, which is in the range of current commercially available conductive inks. Finally, the new Ag NP/NC-based conductive inks have been tested to fabricate NFC antennas by screen-printing onto NC-coated paper, demonstrating to be operative.

  • 26.
    Moon, R. J.
    et al.
    USDA Forest Service, USA.
    Hensdal, C. L.
    Stora Enso Pulp & Paper Asia AB, Sweden.
    Beck, S.
    Calgary, Canada.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Massa, papper och förpackningar.
    Costa, J.
    WebTech Pulp & Paper Technologies, Brazil.
    Kojima, E.
    Nanocellulose Japan, Japan.
    Abitbol, Tiffany
    EPFL Institute of Materials, Switzerland.
    Raghuwanshi, V.
    Monash University, Australia.
    Walker, C.
    University of Maine, USA.
    Batchelor, W.
    Monash University, USA.
    Setting priorities in CNF particle size measurement: What is needed vs. what is feasible2023Inngår i: TAPPI Journal, ISSN 0734-1415, Vol. 22, nr 2, s. 116-137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Measuring the size of cellulose nanomaterials can be challenging, especially in the case of branched and entangled cellulose nanofibrils (CNFs). The International Organization for Standardization, Technical Committee 6, Task Group 1—Cellulosic Nanomaterials, is exploring opportunities to develop standard methods for the measurement of CNF particle size and particle size distribution. This paper presents a summary of the available measuring techniques, responses from a survey on the measurement needs of CNF companies and researchers, and outcomes from an international workshop on cellulose nanofibril measurement and standardization. Standardization needs differed among groups, with Japanese companies mostly requiring measurements for product specification and production control, and other companies mostly needing measurements for safety/regula-tory purposes and for grade definitions in patents. Among all the companies, average length and width with percen-tiles (D(10), D(50), D(90)) were the most desired measurands. Workshop participants concurred that defining the location(s) on the CNF at which to measure the width and the length is an urgent and complex question. They also agreed that methods are needed for rapid particle size measurement at the nanoscale. Our recommendation within ISO is to start work to revise the definition of CNFs and develop sample preparation and measurement guidelines. It was also recommended that further research be done to reproducibly prepare hierarchical branched CNF structures and characterize them, develop automated image analysis for hierarchical branched CNF structures, and develop a classification system encompassing measurements at multiple size ranges from micro-to nanoscale to fully characterize and distinguish CNF samples. 00327-2022 

  • 27. Munier, P.
    et al.
    Gordeyeva, K.
    Bergström, L.
    Fall, Andreas
    Stockholm University, Sweden; MIT, Sweden; Institute of Soldiers Nanotechnologies, USA.
    Directional Freezing of Nanocellulose Dispersions Aligns the Rod-Like Particles and Produces Low-Density and Robust Particle Networks2016Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, nr 5, s. 1875-1881Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that unidirectional freezing of nanocellulose dispersions produces cellular foams with high alignment of the rod-like nanoparticles in the freezing direction. Quantification of the alignment in the long direction of the tubular pores with X-ray diffraction shows high orientation of cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) at particle concentrations above 0.2 wt % (CNC) and 0.08 wt % (CNF). Aggregation of CNF by pH decrease or addition of salt significantly reduces the particle orientation; in contrast, exceeding the concentration where particles gel by mobility constraints had a relatively small effect on the orientation. The dense nanocellulose network formed by directional freezing was sufficiently strong to resist melting. The formed hydrogels were birefringent and displayed anisotropic laser diffraction patterns, suggesting preserved nanocellulose alignment and cellular structure. Nondirectional freezing of the hydrogels followed by sublimation generates foams with a pore structure and nanocellulose alignment resembling the structure of the initial directional freezing. 

  • 28.
    Navarro, J. R. G.
    et al.
    Stockholm University, Sweden.
    Conzatti, G.
    Stockholm University, Sweden.
    Yu, Y.
    Stockholm University, Sweden.
    Fall, Andreas
    Stockholm University, Sweden.
    Mathew, R.
    Stockholm University, Sweden.
    Edén, M.
    Stockholm University, Sweden.
    Bergström, L.
    Stockholm University, Sweden.
    Multicolor Fluorescent Labeling of Cellulose Nanofibrils by Click Chemistry2015Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 16, nr 4, s. 1293-1300Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    (Figure Presented) We have chemically modified cellulose nanofibrils (CNF) with furan and maleimide groups, and selectively labeled the modified CNF with fluorescent probes; 7-mercapto-4-methylcoumarin and fluorescein diacetate 5-maleimide, through two specific click chemistry reactions: Diels-Alder cycloaddition and the thiol-Michael reaction. Characterization by solid-state 13C NMR and infrared spectroscopy was used to follow the surface modification and estimate the substitution degrees. We demonstrate that the two luminescent dyes could be selectively labeled onto CNF, yielding a multicolor CNF that was characterized by UV/visible and fluorescence spectroscopies. It was demonstrated that the multicolor CNF could be imaged using a confocal laser scanning microscope. 

  • 29.
    Nordenström, Malin
    et al.
    KTH Royal Institute of Technology, Sweden.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Nyström, Gösta
    ETH Zurich, Switzerland.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Formation of Colloidal Nanocellulose Glasses and Gels2017Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 33, nr 38, s. 9772-9780Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocellulose (NC) suspensions can form rigid volume-spanning arrested states (VASs) at very low volume fractions. The transition from a free-flowing dispersion to a VAS can be the result of either an increase in particle concentration or a reduction in interparticle repulsion. In this work, the concentration-induced transition has been studied with a special focus on the influence of the particle aspect ratio and surface charge density, and an attempt is made to classify these VASs. The results show that for these types of systems two general states can be identified: glasses and gels. These NC suspensions had threshold concentrations inversely proportional to the particle aspect ratio. This dependence indicates that the main reason for the transition is a mobility constraint that, together with the reversibility of the transition, classifies the VASs as colloidal glasses. If the interparticle repulsion is reduced, then the glasses can transform into gels. Thus, depending on the preparation route, either soft and reversible glasses or stiff and irreversible gels can be formed. 

  • 30. Nyström, G.
    et al.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Carlsson, L.
    Wågberg, L.
    Aligned cellulose nanocrystals and directed nanoscale deposition of colloidal spheres2014Inngår i: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 3, s. 1591-1599Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose nanocrystals are aligned in wrinkled polydimethylsiloxane templates and transferred to polyethyleneimine-coated silica surfaces in a printing process similar to microcontact printing. The highly aligned nanorods were deposited onto the surfaces with a line-to-line distance of 225-600 nm without loss of alignment. It was also possible to repeat the transfer process on the same surface at a 90-degree angle to create a network structure. This demonstrates the versatility of the technique and creates more options for advanced multilayering of materials. To demonstrate that the surface properties of the anionic cellulose nanorods were unaffected by the transfer process and to prove the concept of functionalizing transferred particles, cationic latex particles were electrostatically self-assembled onto the cellulose nanorods. The directed deposition of these particles resulted in excellent site specificity and the highest resolution to date for controlled deposition of colloids on an electrostatically patterned surface.

  • 31.
    Rosén, Tomas
    et al.
    Stony Brook University, USA; KTH Royal Institute of Technology, Sweden.
    He, HongRui
    Stony Brook University, USA.
    Wang, Ruifu
    Stony Brook University, USA.
    Zhan, Chengbo
    Stony Brook University, USA.
    Chodankar, Shirish
    Brookhaven National Laboratory, USA.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Larsson, Per Tomas
    RISE Research Institutes of Sweden. KTH Royal Institute of Technology, Sweden.
    Lindström, Tom
    Stony Brook University, USA.
    Hsiao, Beenjamin
    Stony Brook University, USA.
    Cross-Sections of Nanocellulose from Wood Analyzed by Quantized Polydispersity of Elementary Microfibrils2020Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, nr 12, s. 16743-16754Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bio-based nanocellulose has been shown to possess impressive mechanical properties and simplicity for chemical modifications. The chemical properties are largely influenced by the surface area and functionality of the nanoscale materials. However, finding the typical cross-sections of nanocellulose, such as cellulose nanofibers (CNFs), has been a long-standing puzzle, where subtle changes in extraction methods seem to yield different shapes and dimensions. Here, we extracted CNFs from wood with two different oxidation methods and variations in degree of oxidation and high-pressure homogenization. The cross-sections of CNFs were characterized by small-angle X-ray scattering and wide-angle X-ray diffraction in dispersed and freeze-dried states, respectively, where the results were analyzed by assuming that the cross-sectional distribution was quantized with an 18-chain elementary microfibril, the building block of the cell wall. We find that the results agree well with a pseudosquare unit having a size of about 2.4 nm regardless of sample, while the aggregate level strongly depends on the extraction conditions. Furthermore, we find that aggregates have a preferred cohesion of phase boundaries parallel to the (110)-plane of the cellulose fibril, leading to a ribbon shape on average. 

  • 32. Schütz, C.
    et al.
    Agthe, M.
    Fall, Andreas
    Stockholm University, Sweden.
    Gordeyeva, K.
    Guccini, V.
    Salajkova, M.
    Plivelic, T. S.
    Lagerwall, J. P. F.
    Salazar-Alvarez, G.
    Bergström, L.
    Rod Packing in Chiral Nematic Cellulose Nanocrystal Dispersions Studied by Small-Angle X-ray Scattering and Laser Diffraction2015Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 23, s. 6507-6513Artikkel i tidsskrift (Fagfellevurdert)
  • 33. Schütz, C.
    et al.
    Sort, J.
    Bacsik, Z.
    Oliynyk, V.
    Pellicer, E.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Wågberg, L.
    Berglund, L.
    Bergström, L.
    Salazar-Alvarez, G.
    Hard and Transparent Films Formed by Nanocellulose-TiO2 Nanoparticle Hybrids2012Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 7, nr 10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of hybrids of nanofibrillated cellulose and titania nanoparticles in aqueous media has been studied. Their transparency and mechanical behavior have been assessed by spectrophotometry and nanoindentation. The results show that limiting the titania nanoparticle concentration below 16 vol% yields homogeneous hybrids with a very high Young’s modulus and hardness, of up to 44 GPa and 3.4 GPa, respectively, and an optical transmittance above 80%. Electron microscopy shows that higher nanoparticle contents result in agglomeration and an inhomogeneous hybrid nanostructure with a concomitant reduction of hardness and optical transmittance. Infrared spectroscopy suggests that the nanostructure of the hybrids is controlled by electrostatic adsorption of the titania nanoparticles on the negatively charged nanocellulose surfaces. 

  • 34.
    Sudheshwar, A.
    et al.
    Empa Swiss Federal Laboratories for Material Science and Technology, Switzerland.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Malinverno, N.
    Empa Swiss Federal Laboratories for Material Science and Technology, Switzerland.
    Hischier, R.
    Empa Swiss Federal Laboratories for Material Science and Technology, Switzerland.
    Nevo, Y.
    Hebrew University, Israel.
    Dhuiège, B.
    GenesInk, France.
    Borras, M.
    LEITAT Technological Center, Spain.
    Chbani, A.
    LEITAT Technological Center, Spain.
    Aucher, C.
    LEITAT Technological Center, Spain.
    Martinez-Crespiera, S.
    LEITAT Technological Center, Spain.
    Eibensteiner, F.
    Prelonic Technologies, Austria.
    Kurzhals, S.
    AIT, Austria.
    Giebelhauser, L.
    AIT, Austria.
    Melnik, E.
    AIT, Austria.
    Mutinati, G. C.
    AIT, Austria.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioekonomi och hälsa.
    Som, C.
    Empa Swiss Federal Laboratories for Material Science and Technology, Switzerland.
    Assessing sustainability hotspots in the production of paper-based printed electronics2023Inngår i: Flexible and Printed Electronics, ISSN 2058-8585, Vol. 8, nr 1, artikkel-id 015002Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Novel printed electronics are projected to grow and be manufactured in the future in large volumes. In many applications, printed electronics are envisaged as sustainable alternatives to conventional (PCB-based) electronics. One such application is in the semi-quantitative drug detection and point-of-care device called ‘GREENSENSE’ that uses paper-based printed electronics. This paper analyses the carbon footprint of GREENSENSE in order to identify and suggest means of mitigating disproportionately high environmental impacts, labeled ‘sustainability hotspots’, from materials and processes used during production which would be relevant in high-volume applications. Firstly, a life cycle model traces the flow of raw materials (such as paper, CNCs, and nanosilver) through the three ‘umbrella’ processes (circuit printing, component mounting, and biofunctionalization) manufacturing different electronic components (the substrate, conductive inks, energy sources, display, etc) that are further assembled into GREENSENSE. Based on the life cycle model, life cycle inventories are modeled that map out the network of material and energy flow throughout the production of GREENSENSE. Finally, from the environmental impact and sustainability hotspot analysis, both crystalline nanocellulose and nanosilver were found to create material hotspots and they should be replaced in favor of lower-impact materials. Process hotspots are created by manual, lab-, and pilot-scale processes with unoptimized material consumption, energy use, and waste generation; automated and industrial-scale manufacturing can mitigate such process hotspots. © 2023 The Author(s).

  • 35.
    Uhlig, Martin
    et al.
    Technische Universität Berlin, Germany.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Wellert, Stefan
    Technische Universität Berlin, Germany.
    Lehmann, Maren
    Technische Universität Berlin, Germany.
    Prevost, Sylvain
    ESRF European Synchrotron, France.
    Wågberg, Lars
    KTH Royal Institute of Technology, .
    von Klitzing, Regine
    Technische Universität Berlin, Germany.
    Nyström, Gustav
    KTH Royal Institute of Technology, Sweden.
    Two-Dimensional Aggregation and Semidilute Ordering in Cellulose Nanocrystals2016Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, nr 2, s. 442-450Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The structural properties and aggregation behavior of carboxymethylated cellulose nanocrystals (CNC-COOH) were analyzed with small angle neutron scattering (SANS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) and compared to sulfuric acid hydrolyzed cellulose nanocrystals (CNC-SO3H). The CNC-COOH system, prepared from single carboxymethylated cellulose nanofibrils, was shown to laterally aggregate into 2D-stacks that were stable both in bulk solution and when adsorbed to surfaces. CNC-SO3H also showed a 2D aggregate structure with similar cross sectional dimensions (a width to height ratio of 8) as CNC-COOH, but a factor of 2 shorter length. SANS and DLS revealed a reversible ordering of the 2D aggregates under semidilute conditions, and a structure peak was observed for both systems. This indicates an early stage of liquid crystalline arrangement of the crystal aggregates, at concentrations below those assessed using birefringence or polarized optical microscopy. 

  • 36.
    Ul Hassan Alvi, Naveed
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. Digital Cellulose Center, Sweden.
    Mulla, Yusuf
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. Digital Cellulose Center, Sweden.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden. Digital Cellulose Center, Sweden.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign. Digital Cellulose Center, Sweden.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. Digital Cellulose Center, Sweden.
    The Fast and One-Step Growth of ZnO Nanorods on Cellulose Nanofibers for Highly Sensitive Photosensors2023Inngår i: Nanomaterials, E-ISSN 2079-4991, Vol. 13, nr 18, artikkel-id 2611Artikkel i tidsskrift (Fagfellevurdert)
    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). 

  • 37. Usov, I.
    et al.
    Nyström, G.
    Adamcik, J.
    Handschin, S.
    Schätz, C.
    Fall, Andreas
    Stockholm University, Sweden.
    Bergström, L.
    Mezzenga, R.
    Understanding nanocellulose chirality and structure-properties relationship at the single fibril level2015Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 6Artikkel i tidsskrift (Fagfellevurdert)
  • 38.
    Wang, Xin
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Grimoldi, Andrea
    Linköping University, Sweden.
    Håkansson, Karl
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi.
    Fall, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Bioraffinaderi och energi.
    Granberg, Hjalmar
    RISE - Research Institutes of Sweden (2017-2019), Bioekonomi, Papperstillverkning och förpackningar.
    Mengistie, Desalegn
    Linköping University, Sweden.
    Edberg, Jesper
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Engquist, Isak
    Linköping University, Sweden.
    Nilsson, David
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Berggren, Magnus
    Linköping University, Sweden.
    Gustafsson, Göran
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Anisotropic conductivity of Cellulose-PEDOT:PSS composite materials studied with a generic 3D four-point probe tool2019Inngår i: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 66, s. 258-264Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The conductive polymer poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) is widely used in organic electronics and printed electronics due to its excellent electronic and ionic conductivity. PEDOT:PSS films exhibit anisotropic conductivities originating from the interplay of film deposition processes and chemical structure. The previous studies found that high boiling point solvent treated PEDOT:PSS exhibits an anisotropy of 3–4 orders magnitude. Even though both the in-plane and out-of-plane conductivities are important for the device performance, the out-of-plane conductivity is rarely studied due to the complexity with the experiment procedure. Cellulose-based paper or films can also exhibit anisotropic behavior due to the combination of their intrinsic fibric structure and film formation process. We have previously developed a conductive paper based on PEDOT:PSS and cellulose which could be used as the electrodes in energy storage devices. In this work we developed a novel measurement set-up for studying the anisotropy of the charge transport in such composite materials. A tool with two parallel plates mounted with spring loaded probes was constructed enabling probing both lateral and vertical directions and resistances from in-plane and out-of-plane directions to be obtained. The measurement results were then input and analyzed with a model based on a transformation method developed by Montgomery, and thus the in-plane and out-of-plane conductivities could be detangled and derived. We also investigated how the conductivity anisotropy depends on the microstructure of the cellulose template onto which the conductive polymer self-organizes. We show that there is a relatively small difference between the in-plane and out-of-plane conductivities which is attributed to the unique 3D-structure of the composites. This new knowledge gives a better understanding of the possibilities and limitations for using the material in electronic and electrochemical devices.

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