This study investigates lignocellulose nanofibrils (LCNF) as a sustainable alternative material for printed circuit board (PCB) substrates, demonstrating an application through the development of an eco-friendly computer mouse demonstrator. LCNF is derived from lignin-rich cellulose pulp, a side stream product of biorefinery processes, combining the natural strength of cellulose fibrils with lignin to enhance mechanical and electrochemical properties. The research outlines the process of fibrillating lignin-rich cellulose pulp at 10 kW/h per kg into LCNF, followed by thermal and pressure treatment (at Δp = 50 – 1500 kN, ΔT = 30 – 120 °C) to achieve a rigid PCB substrate. Comprehensive characterization of the LCNF substrate included assessments of its mechanical properties (flexural and tensile testing), dimensional stability, electrical properties, surface uniformity and thermal conductivity. The LCNF PCB was integrated in a computer mouse demonstrator featuring inkjet printing of circuit layouts and electronic component assembly, while the mouse housing was designed and 3D-printed using eco-friendly Wood-PLA filament. Electrical properties characterization of the printed circuit and resulting functionality of the computer mouse showcases a sustainable approach to eco-electronics using wood-derived materials. This study underscores the potential of wood-derived nanomaterials like LCNF to reduce electronic waste (e-waste) associated with conventional PCB materials and promote the development of a more eco-friendly electronics, contributing to sustainable, high-performance ecoPCBs and advancing green technology.

Cellulose nanomaterials are a promising material for the stabilization of degraded paper, since their characteristics in composition, structure and physical properties are close to those of cellulose. Two types of nanocellulose were tested regarding their performance in stabilizing fragile papers: cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC). The suspensions were applied to a pure cellulose paper and historical newspaper. The study included optical and microscopic characterization, determination of pH, conductivity, and rheology as well as measurement of changes in tensile strength after treatment. The results showed that the pH, as well as the optical and haptic properties, were not altered after treatment. A 50% increase in paper’s tensile strength is achieved with 3% CNC applied on the paper. In addition, fluorescence microscopy demonstrated that, due to their nanoscale dimension, the suspensions can reinforce the surface but also fully penetrate the paper matrix achieving therefore an overall stabilization.

Structural characterization techniques are fundamental to correlate the material macro-, nano-, and molecular-scale structures to their macroscopic properties and to engineer hierarchical materials. Here, we combine X-ray transmission with scanning small- and wide-angle X-ray scattering (sSWAXS) to investigate ultraporous and lightweight biopolymer-based foams using cellulose nanofibrils (CNFs) as building blocks. The power of multimodal sSWAXS for multiscale structural characterization of self-assembled CNFs is demonstrated by spatially resolved maps at the macroscale (foam density and porosity), at the nanoscale (foam structural compactness, CNF orientation in the foam walls, and CNF packing state), and at the molecular scale (cellulose crystallite dimensions). Specifically, we compare the impact of freeze-thawing-drying (FTD) fabrication steps, such as static/stirred freezing and thawing in ethanol/water, on foam structural hierarchy spanning from the molecular to the millimeter scale. As such, we demonstrate the potential of X-ray scattering imaging for hierarchical characterization of biopolymers.

In recent years, there is rising attention paid to biodegradable, recyclable, carbon-neutral, and affordable materials, especially those derived from natural plants and wood. Microfibrillated cellulose (MFC) fibers derived from natural resources have received particular interest due to their unique morphological features and superb mechanical properties for “green” materials in the future. The general goal of this study is to give a comprehensive review on the latest progress toward (1) production of MFC in more efficient and economic methods; and (2) the fabrication of MFC-based composite materials in scalable routes. Moreover, this study is to give an overview of the latest progress on this topic and more information on the main barriers and limitations for successful use of MFC in high-performance composite materials at scale. Based on these points, the most interesting studies addressing the identified obstacles were highlighted and discussed in detail, and the pros and cons of the commonly used approaches and techniques were covered. By doing so, this chapter intends to specifically shed light on the latest advances in this field and to bring inspiration for shaping renewable and green materials from MFC in the future.

Elastomer composites are prepared by infiltrating polydimethylsiloxane (PDMS) into a porous ceramic structure of nanoparticles. This method differs from the conventional approach, where particles are dispersed into the polymer matrix, since here, the polymer is incorporated into a pre-sintered structure of nanoparticles by infil-tration under vacuum. Several oxides (CoFe2O4, ZnO, BaTiO3, BiFeO3, and BiFeO3 doped with yttrium), commonly used for dielectric and piezoelectric devices, were infiltrated by PDMS. The porous 3D structure of nanoparticles is obtained by using cellulose as a scaffold and binder, which is eliminated during the process. Thus, the so-called (3,3) composites are obtained, where the particles are in direct contact (although immersed in the polymer), at relatively low loading. The dielectric behaviour of the infiltrated and conventional composites is determined by impedance spectroscopy, dielectric polarization analysis, determinations of electric breakdown -field (EBD), and static dielectric constant (es). The percentage increase of es from conventional to infiltrated composites is remarkable, reaching for BiFeO3-Y, an increase of es and e '(omega) larger than 600 %, while EBD de-creases by a factor of 3.

Robots are often used for sensing and sampling in natural environments. Within this area, soft robots have become increasingly popular for these tasks because their mechanical compliance makes them safer to interact with. Unfortunately, if these robots break while working in vulnerable environments, they create potentially hazardous waste. Consequently, the development of compliant, biodegradable structures for soft, eco-robots is a relevant research area that we explore here. Cellulose is one of the most abundant biodegradable materials on earth, but it is naturally very stiff, which makes it difficult to use in soft robots. Here, we look at both biologically and kirigami inspired structures that can be used to reduce the stiffness of cellulose based parts for soft robots up to a factor of 19 000. To demonstrate this, we build a compliant force and displacement sensing structure from microfibrillated cellulose. We also describe a novel manufacturing technique for these structures, provide mechanical models that allow designers to specify their stiffness, and conclude with a description of our structure's performance.

Art restoration poses many challenges for scientists and conservators, as any restorative action can lead to lasting modification or damage to the original artefact. Recent interest in gel encapsulation has grown due to the ability to control the cleaning action; yet the restoration of modern paints such as acrylic-based systems still presents issues due to their extremely high sensitivity to most solvents. Herein, the preparation of dual physically and chemically crosslinked hydrogels based on regenerated cellulose and cinnamoyl-modified gelatin is demonstrated. These dual crosslinked hydrogels show increased mechanical strength and enhanced water retention compared to pure physically crosslinked hydrogels. When applied to acrylic-based paint surfaces, the dual crosslinked hydrogels extract a smaller amount of hydrophilic additives (albeit still leading to swelling within the paint film) versus physically crosslinked gels. It is anticipated that this dual crosslinking approach can be broadly applied to prepare gels for conservation of cultural heritage artefacts.

Cellulose nanofibril foams are cellulose-based porous materials with outstanding mechanical properties, resulting from the high strength-to-weight ratio of nanofibrils. Here we report the development of an optimized fabrication process for highly porous cellulose foams, based on a well-controlled freeze-thawing-drying (FTD) process at ambient pressure. This process enables the fabrication of foams with ultra-high porosity, up to 99.4%, density of 10 mg/cm(3), and liquid (such as oil) absorption capacity of 100 L/kg. The proposed approach is based on the ice-templating of nanocellulose suspension in water, followed by thawing in ethanol and drying at environmental pressures. As such, the proposed fabrication route overcomes one of the major bottle-necks of the classical freeze-drying approach, by eliminating the energy-demanding vacuum drying step required to avoid wet foam collapse upon drying. As a result, the process is simple, environmentally friendly, and easily scalable. Details of the foam development fabrication process and functionalization are thoroughly discussed, highlighting the main parameters affecting the process, e.g., the concentration of nanocellulose and additives used to control the ice nucleation. The foams are also characterized by mechanical tests and oil absorption measurements, which are used to assess the foam absorption capability as well as the foam porosity. Compound water-in-oil drop impact experiments are used to demonstrate the potential of immiscible liquid separation using cellulose foams.

Temperature sensitivity of bitumen modified with acetylated microfibrillated cellulose (MFCac), both in the low and high temperature ranges, is significantly decreased. The complex shear modulus for an MFCac content of 2 wt% was 10 times higher than for bitumen alone. In addition the phase angle at high temperatures indicates increased elastic behavior that results in favorable properties with respect to rutting. On the low temperature side (-25 degrees C), the deformation to failure in fracture toughness tests was around 100 times higher with MFCac modified bitumen than for the non-modified one whereas the failure forces were similar.

This paper takes a comparative approach in characterizing two types of nano-scale cellulosic particles obtained using chemical-free pathways, either by nearcritical water treatment or by high-shear homogenization from the same microcrystalline cellulose (MCC). The nearcritical water treatment efficiently depolymerized cellulose, producing a solid precipitated fraction of low-molecular-weight material containing cellulose II, while homogenization mechanically deconstructed MCC without altering its molecular structure. Both pathways yielded nanocellulose-like materials yet with different morphologies. The mechanically produced, rod-like particles were obtained with high yield. In contrast, the hydrothermal precipitate exhibited more hydrophobic ribbon-like particles that provided a greater level of particle-particle interaction. Both materials successfully acted as stabilizers for oil-in-water Pickering emulsions; however, the hydrothermally-produced material exhibited superior performance, with stable emulsions obtained upon addition of as low as 1.0wt.% cellulose. These two pathways are highly relevant for altering the structure and properties of MCC and for formulating new, sustainably produced nanocellulose-based materials.

Microfibrillated cellulose (MFC) is continuously gaining attention due to its outstanding mechanical properties, in particular high strength-to-weight ratio. Recently, more and more studies target the production of porous materials, such as foams, out of this natural resource. Commonly, an energy-consuming freeze–drying method is utilized for producing pure MFC porous structures from water-based suspensions, which renders these products particularly unattractive for industry. Although alternatives for foam production have been proposed, using either modified MFC or with various additives, the freeze–drying step is still one of the most critical bottle-neck of MFC foam production upscaling. A novel straightforward freeze–thawing–drying procedure assisted by the common additive urea was herein proposed. Such method allows the production of mechanically stable, lightweight MFC structures under low-cost ambient conditions drying. The influence of the cellulose fibril characteristics, the suspension formulation and the process parameters on the final foam properties have been studied in terms of porosity, density and mechanical properties.

Nanofibrillated cellulose (NFC) was used as bio-based stabilizing agent in the heterophase polymerization of methyl methacrylate (MMA) to nanoscale poly(methyl methacrylate) (PMMA) spheres. NFC/MMA suspensions at different NFC/MMA ratios were prepared in water, and the suspension stability was evaluated before the subsequent polymerization. The resulting polymerization products as well as products from several control experiments were analyzed via optical microscopy, SEM, and isolation experiments associated with thermogravimetric analysis. PMMA spheres had diameters in the range of 150–250 nm and were regularly distributed within the NFC network, whereas NFC acted as a stabilizer during the polymerization. The appearance of the resulting PMMA spheres within the NFC network was influenced by different factors, such as the reaction conditions, the initiator, and the solubility of the monomer.

Inverted PTB7/PC71BM polymer solar cells are prepared on solution-processed Al:ZnO transparent contacts on PET substrates. Al:ZnO is deposited by a low temperature chemical bath deposition route (T < 100°C at any step) to comply with the temperature sensitive substrate. A maximum conversion efficiency of 6.4% and 6.9% is achieved for the indium-free solar cells on PET and glass substrates, respectively. The devices are relatively stable in air whereby an initial efficiency loss in the order of 15% after storage for 15 days can be fully recovered by light soaking.

One of the most challenging aspects of using nanofibrillated cellulose (NFC) for membranes production is their limited permeance. When NFC membranes are produced from aqueous suspensions, depending on their grammage, the permeances are in the range of a few decades of L/(hm(2)MPa) not matching satisfactory filtration times. We present a fast and sustainable solution to increase the permeances of such membranes through a combination of solvent exchange of the NFC suspension with ethanol and the use of a removable template, a mixture of calcium compounds (CC). The effect of the CC/NFC ratio was screened for various concentrations. The permeance of water could be increased by as much as 2-3 times as compared to nontemplated membranes. Further, the membranes showed the ability for penetration of water-soluble macromolecules, contaminant rejection of suspended solid particles, and thus fluids (such as orange juice) could be concentrated, with a view to applications in food industry.

Heptamethine Iodide and heptamethine hexafluorophosphate solutions in various solvents (chloroform, dichloromethane, ethanol and toluene) were studied spectrophotometrically and spectrofluorimetrically as X-ray and gamma-ray dosimeters for the detection of low-dose radiation. The useful dose range was found to be between 0 to 1 Gy and 1 to 30 Gy for the concentrations studied. The effects of temperature and light on the stability of response during pre-irradiation and post-irradiation storage, the effects of different solvents and dose rates on dosimetric responses of these dyes were also investigated. The results of our studies show that these dye solutions are quite stable in the dark at low as well as room temperature and could be used as dosimeters for low dose X-ray and gamma radiation in medical dosimetry for radiotherapy treatment planning. They can also be used as dosimeters in personal radiation safety applications and environmental radiation monitoring. They have constant sensitivity and their detection limit is an order of magnitude lower than recently reported in the literature. These dyes are and were used in photography industry, so they are cheap and easy to buy. Keywords: Dosimeter, gamma-ray, heptamethine hexafluorophosphate, heptamethine iodide, low-dose, X-ray.

Simple bilayer organic solar cells rely on very thin coated films that allow for effective light absorption and charge carrier transport away from the heterojunction at the same time. However, thin films are difficult to coat on rough substrates or over large areas, resulting in adverse shorting and low device fabrication yield. Chemical p-type doping of organic semiconductors can reduce Ohmic losses in thicker transport layers through increased conductivity. By using a Co(III) complex as chemical dopant, we studied doped cyanine dye/C-60 bilayer solar cell performance for increasing dye film thickness. For films thicker than 50 nm, doping increased the power conversion efficiency by more than 30%. At the same time, the yield of working cells increased to 80%. We addressed the fate of the doped cyanine dye, and found no influence of doping on solar cell long term stability.

Heat dissipation is an important issue in many electronic devices and therefore materials showing high thermal conductivity are required for their construction and packaging. The intrinsically low thermal conductivity of polymeric materials can be improved when employing (nano-) composites; however, the required high filler content then renders these materials opaque. This paper reports on a composite material that combines high transparency and improved thermal conductivity by using calcium fluoride (CaF2) particles in a silicone elastomer. The refractive index of the silicone matrix is matched to the filler material, light scattering is prevented, and transparent composites with enhanced thermal conductivity at modest filler content (starting at 0.2 volume fraction) are obtained.