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The degree of crystallinity in cellulose significantly affects the physical, mechanical, and chemical properties of cellulosic materials, their processing, and their final application. Measuring the crystalline structures of cellulose is a challenging task due to inadequate consistency among the variety of analytical techniques available and the lack of absolute crystalline and amorphous standards. Our article reviews the primary methods for estimating the crystallinity of cellulose, namely, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), Raman and Fourier-transform infrared (FTIR) spectroscopy, sum-frequency generation vibrational spectroscopy (SFG), as well as differential scanning calorimetry (DSC), and evolving biochemical methods using cellulose binding molecules (CBMs). The techniques are compared to better interrogate not only the requirements of each method, but also their differences, synergies, and limitations. The article highlights fundamental principles to guide the general community to initiate studies of the crystallinity of cellulosic materials. [ABSTRACT FROM AUTHOR]

Surface treatments of cellulose triacetate (CTA) films via atmospheric pressure plasmas containing helium and either O2 or C3F6 as plasma reactive gas were performed to study their effects on moisture barrier, transmittance, thermal, surface chemistry, and morphological properties. Plasma treated CTA films were characterized using X-ray photoelectron spectroscopy (XPS), attenuated total reflectance-Fourier transform infrared spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy analytical techniques. Both surface chemical and morphological changes were correlated with water vapor transmission rates (WVTRs) and contact angle measurements. XPS spectra showed that the relative chemical composition of the C 1s spectra after O2 plasma treatments exhibits an increase in the relative amount of C--C bonds, which may be due to a change in surface cross-linking. ToF-SIMS spectra showed the depth of treatment of atmospheric plasma treatment of CTA films at about 100 nm. The WVTR of the CTA film was reduced up to 20% after sustainable atmospheric O2/helium plasma, while no significant changes were observed in light transmittance. Thus, the use of sustainable atmospheric plasmas to enhance moisture barrier while maintaining other critical properties such as light transmittance, thermal stability, and morphology of a CTA film could provide significant benefits to the electronics industry. [ABSTRACT FROM AUTHOR]

Optimizing drying energy in the forest products industry is critical for integrating lignocellulosic feedstocks across all manufacturing sectors. Despite substantial efforts to reduce thermal energy consumption during drying, further enhancements are possible. Cellulose, the main component of forest products, is Earth's most abundant biopolymer and a promising renewable feedstock. This study employs all-atom molecular dynamics (MD) simulations to explore the structural dynamics of a small I β -cellulose microcrystallite and surrounding water layers during drying. Molecular and atomistic profiles revealed localized water near the cellulose surface, with water structuring extending beyond 8 Å into the water bulk, influencing solvent-accessible surface area and solvation energy. With increasing temperature, there was a ∼20 % reduction in the cellulose surface available for interaction with water molecules, and a ∼22 % reduction in solvation energy. The number of hydrogen bonds increased with thicker water layers, facilitated by a "bridging" effect. Electrostatic interactions dominated the intermolecular interactions at all temperatures, creating an energetic barrier that hinders water removal, slowing the drying processes. Understanding temperature-dependent cellulose-water interactions at the molecular level will help in designing novel strategies to address drying energy consumption, advancing the adoption of lignocellulosics as viable manufacturing feedstocks. [Display omitted] [ABSTRACT FROM AUTHOR]

Based on publications related to the use of micro- and nanofibrillated cellulose (MNFC) in papermaking applications, three sets of parameters (intrinsic and extrinsic variables, furnish composition, and degree of dispersion) were proposed. This holistic approach intends to facilitate understanding and manipulation of the main factors describing the colloidal behavior in systems comprising of MNFC, pulp fibers, and additives, which directly impact paper product performance. A preliminary techno-economic assessment showed that cost reductions driven by the addition of MNFC in paper furnishes could be as high as USD 149 per ton of fiber (up to 20% fiber reduction without adverse effects on paper's strength) depending on the cost of papermaking fibers. It was also determined that better performance in terms of strength development associated with a higher degree of MNFC fibrillation offset its high manufacturing cost. However, there is a limit from which additional fibrillation does not seem to contribute to further strength gains that can justify the increasing production cost. Further research is needed regarding raw materials, degree of fibrillation, and combination with polyelectrolytes to further explore the potential of MNFC for the reduction of weight of paper products. [ABSTRACT FROM AUTHOR]

Efficient utilization of forestry, agriculture, and marine resources in various manufacturing sectors requires optimizing fiber transformation, dewatering, and drying energy consumption. These processes play a crucial role in reducing the carbon footprint and boosting sustainability within the circular bioeconomy framework. Despite efforts made in the paper industry to enhance productivity while conserving resources and energy through lower grammage and higher machine speeds, reducing thermal energy consumption during papermaking remains a significant challenge. A key approach to address this challenge lies in increasing dewatering of the fiber web before entering the dryer section of the paper machine. Similarly, the production of high-value-added products derived from alternative lignocellulosic feedstocks, such as nanocellulose and microalgae, requires advanced dewatering techniques for techno-economic viability. This critical and systematic review aims to comprehensively explore the intricate interactions between water and lignocellulosic surfaces, as well as the leading technologies used to enhance dewatering and drying. Recent developments in technologies to reduce water content during papermaking, and advanced dewatering techniques for nanocellulosic and microalgal feedstocks are addressed. Existing research highlights several fundamental and technical challenges spanning from the nano- to macroscopic scales that must be addressed to make lignocellulosics a suitable feedstock option for industry. By identifying alternative strategies to improve water removal, this review intends to accelerate the widespread adoption of lignocellulosics as feasible manufacturing feedstocks. Moreover, this review aims to provide a fundamental understanding of the interactions, associations, and bonding mechanisms between water and cellulose fibers, nanocellulosic materials, and microalgal feedstocks. The findings of this review shed light on critical research directions necessary for advancing the efficient utilization of lignocellulosic resources and accelerating the transition towards sustainable manufacturing practices. [Display omitted] • One key strategic issue facing the forest products industry is the high energy requirements. • The nature of interactions, association, and bonding of lignocelluloses is essential. • Alternative enzymatic treatments targeting the fiber surface can increase dryness while reducing the need for refining. • An understanding of floc formation and micro and nano-fines migration mechanisms is required. • Nanocellulose and microalgal dewatering is critical to enable braoder applicaitons. [ABSTRACT FROM AUTHOR]

Flexible-hybrid printed electronics (FHPE) is a rapidly growing discipline that may be described as the precise imprinting of electrically functional traces and components onto a substrate such as paper to create functional electronic devices. The mass production of low-cost devices and components such as environmental sensors, bio-sensors, actuators, lab on chip (LOCs), radio frequency identification (RFID) smart tags, light emitting diodes (LEDs), smart fabrics and labels, wallpaper, solar cells, fuel cells, and batteries are major driving factors for the industry. Using renewable and bio-friendly materials would be advantageous for both manufacturers and consumers with the increased use of (FHPE) electronics in our daily lives. This review article describes recent developments in cellulose and nanocellulose-based materials for FHPE, and the necessary developments required to propagate their use in commercial applications. The aim of these developments is to enable the creation of FHPE devices and components made almost entirely of cellulose materials. [ABSTRACT FROM AUTHOR]

This review article was prompted by a remarkable growth in the number of scientific publications dealing with the use of nanocellulose (especially nanofibrillated cellulose (NFC), cellulose nanocrystals (CNC), and bacterial cellulose (BC)) to enhance the barrier properties and other performance attributes of new generations of packaging products. Recent research has confirmed and extended what is known about oxygen barrier and water vapor transmission performance, strength properties, and the susceptibility of nanocellulose-based films and coatings to the presence of humidity or moisture. Recent research also points to various promising strategies to prepare ecologically-friendly packaging materials, taking advantage of nanocellulose-based layers, to compete in an arena that has long been dominated by synthetic plastics. Some promising approaches entail usage of multiple layers of different materials or additives such as waxes, high-aspect ratio nano-clays, and surface-active compounds in addition to the nanocellulose material. While various high-end applications may be achieved by chemical derivatization or grafting of the nanocellulose, the current trends in research suggest that high-volume implementation will likely incorporate water-based formulations, which may include water-based dispersions or emulsions, depending on the enduses. [ABSTRACT FROM AUTHOR]

Transparent and High Barrier Plasma Functionalized Acrylic Coated Cellulose Triacetate Films. • Fabrication of transparent and high barrier coated cellulose triacetate (CTA) films. • Enhanced adhesion and curing of acrylic coatings via atmospheric plasma treatments. • Significant reduction in WVTR while maintaining excellent transparency. • Modulation of surface texture via plasma compositions and crosslinking agents. Transparent and high moisture barrier acrylic coatings were obtained by deposition of acrylic resin containing crosslinking agents onto cellulose ester films, followed by exposure to atmospheric plasma. The effects of monomers, crosslinking agents, and polymerization methods were studied. The surface chemical composition, morphology, water vapor transmission rate (WVTR), light transmittance, and adhesion performance of the coated cellulose triacetate (CTA) films were characterized for the acrylic coated films and for different plasma treatments. Coated films showed a significant reduction in water vapor permeability while maintaining excellent transparency when compared with uncoated films. Furthermore, adhesion of the coating to the CTA film was also improved due to plasma treatment. It was also found that plasma curing on the coated oligomers can induce morphological changes and significantly increase surface roughness and hydrophilicity. The roughness texture observed via SEM analysis indicated that the types of plasma polymerization and the amount of crosslinking agents control the texture types for acrylic coating. Plasma-assisted acrylic coated CTA films can be used in electronic displays, medical, and packaging applications. [ABSTRACT FROM AUTHOR]

• Tunable poly(N-Isopropylacrylamide)-cellulose nanofibrils hydrogel films. • Fabrication using inverted SLA 3D printing to provide a new manufacturing platform. • Switchable bio-adhesion to bacteria depending on the CNF content and distribution. • Unique thermo-responsivity and tunable optical performance. • Modulation of LCST (∼ 8 °C reduction) relative to pure PNIPAm hydrogel films. A hybrid poly(N-isopropylacrylamide) (PNIPAm)/cellulose nanofibrils (CNFs) hydrogel composite was fabricated by inverted stereolithography 3D printing to provide a new platform for regulating lower critical solution temperature (LCST) properties and thus tuning optical and bioadhesive properties. The phenomena of interest in the as-printed PNIPAm/CNF hydrogels may be attributed to the fiber-reinforced composite system between crosslinked PNIPAm and CNFs. The optical tunability was found to be correlated to the micro/nano structures of the PNIPAm/CNF hydrogel films. It was found that PNIPAm/CNF hydrogels exhibit switchable bioadhesivity to bacteria in response to CNF distribution in the hydrogels. After 2.0 wt% CNF was incorporated, it was found that a remarkable 8°C reduction of the LCST was achieved relative to PNIPAm hydrogel crosslinked by TEGDMA without CNF. The prepared PNIPAm/CNF hydrogels possessed highly reversible optical, bioadhesion, and thermal performance, making them suitable to be used as durable temperature-sensitive sensors and functional biomedical devices. [ABSTRACT FROM AUTHOR]

• CNF/MWCNTs films with a structure of semi-interpenetrating networks were fabricated. • Percolation threshold level of CNF/MWCNTs membranes of 1.88 wt% was achieved. • CNF/MWCNTs films with 10 wt% MWCNTs showed a high conductivity value of 37.6 S/m. • Resistances of CNF/MWCNTs films were affected by bending states to a minor extent. • Capacitance of the pressure sensors was almost linearly dependent on pressure. Highly conductive multi-walled carbon nanotubes (MWCNTs) and flexible cellulose nanofibers (CNF) membranes with semi-interpenetrating networks structure were fabricated using the typical paper-making method, which was simple and cost-effective. The Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR), and thermal gravimetric analysis (TGA) were used to estimate the morphology, chemical structure, and thermal stability of the membranes. The mechanical, optical, and electrical properties of the membranes were characterized with a uniaxial tensile testing machine, ultraviolet visible spectroscope, and digital multimeter, respectively. The results indicated that the membranes containing 10 wt% of MWCNTs showed a high conductivity value of 37.6 S/m, and the sheet resistances of the membranes were stable at different bending states. Furthermore, we demonstrated the electrical features of membrane-based capacitive pressure sensors based on CNF/MWCNTs. The proposed method for fabricating CNF/MWCNTs membranes can simplify the production process and have great practical potential in various electronics applications such as touch screens. [ABSTRACT FROM AUTHOR]