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This review summarizes the preparation methods of cellulose nanofibrils (CNFs) and the progress in the research pertaining to their surface modification. Moreover, the preparation and surface modification of nanocellulose were comprehensively introduced based on the existing literature. The review focuses on the mechanical treatment of cellulose, the surface modification of fibrillated fibers during pretreatment, the surface modification of nanocellulose and the modification of CNFs and their functional application. In the past five years, research on cellulose nanofibrils has progressed with developments in nanomaterials research technology. The number of papers on nanocellulose alone has increased by six times. However, owing to its high energy consumption, high cost and challenging industrial production, the applications of nanocellulose remain limited. In addition, although nanofibrils exhibit strong biocompatibility and barrier and mechanical properties, their high hydrophilicity limits their practical application. Current research on cellulose nanofibrils has mainly focused on the industrial production of CNFs, their pretreatment and functional modification and their compatibility with other biomass materials. In the future, with the rapid development of modern science and technology, the demand for biodegradable biomass materials will continue to increase. Furthermore, research on bio-based nanomaterials is expected to advance in the direction of functionalization and popularization.

Designing lightweight nanostructured aerogels for high‐performance electromagnetic interference (EMI) shielding is crucial yet challenging. Ultrathin cellulose nanofibrils (CNFs) are employed for assisting in building ultralow‐density, robust, and highly flexible transition metal carbides and nitrides (MXenes) aerogels with oriented biomimetic cell walls. A significant influence of the angles between oriented cell walls and the incident EM wave electric field direction on the EMI shielding performance is revealed, providing an intriguing microstructure design strategy. MXene “bricks” bonded by CNF “mortars” of the nacre‐like cell walls induce high mechanical strength, electrical conductivity, and interfacial polarization, yielding the resultant MXene/CNF aerogels an ultrahigh EMI shielding performance. The EMI shielding effectiveness (SE) of the aerogels reaches 74.6 or 35.5 dB at a density of merely 8.0 or 1.5 mg cm–3, respectively. The normalized surface specific SE is up to 189 400 dB cm2 g–1, significantly exceeding that of other EMI shielding materials reported so far. Oriented biomimetic hybrid cell walls of nanocellulose‐MXene aerogels for tunable electromagnetic interference shielding and mechanism are represented by a yin‐yang symbol. Herein, the blue and red regions in the symbol correspond to angles with a smaller and larger transmission of the incident EM waves, respectively.

Cellulose nanofibrils (CNF) are increasingly explored for biomedical applications; however, the relationship between surface functionalization and biological responses remains incompletely understood. In this study, CNF were carboxymethylated to controlled degrees of substitution (DS) using kraft pulp as a starting material, and their physicochemical properties and in vitro biosafety were evaluated. Increasing DS altered crystallinity and surface charge, resulting in measurable changes in zeta potential and structural characteristics. Cell viability was assessed in HepG2, HEK293, and RAW 264.7 cells across a concentration range of 100 to 1000 µg/mL using complementary assays. All tested materials exhibited concentration-dependent trends in cell viability. However, under the tested conditions, the observed effects remained within the non-cytotoxic range. Among the tested samples, CM CNF with DS 0.2 showed stable cell viability and limited apoptosis-related responses comparable to those of hyaluronic acid (HA), while samples with lower or higher substitution levels showed modest reductions in viability at higher concentrations. Apoptosis-related gene and protein expression analyses further indicated limited transcriptional and translational changes relative to the vehicle-treated control. Overall, the findings suggest that the degree of carboxymethylation influences cell–material interactions in a concentration-dependent manner, while maintaining biosafety within the tested DS range.

Cellulose nanomaterials (CNs) are of increasing interest due to their appealing inherent properties such as bio-degradability, high surface area, light weight, chirality and the ability to form effective hydrogen bonds across the cellulose chains or within other polymeric matrices. Extending CN self-assembly into multiphase polymer structures has led to useful end-results in a wide spectrum of products and countless innovative applications, for example, as reinforcing agent, emulsion stabilizer, barrier membrane and binder. In the current contribution, after a brief description of salient nanocellulose chemical structure features, its types and production methods, we move to recent advances in CN utilization as an ecofriendly binder in several disparate areas, namely formaldehyde-free hybrid composites and wood-based panels, papermaking/coating processes, and energy storage devices, as well as their potential applications in biomedical fields as a cost-effective and tissue-friendly binder for cartilage regeneration, wound healing and dental repair. The prospects of a wide range of hybrid materials that may be produced via nanocellulose is introduced in light of the unique behavior of cellulose once in nano dimensions. Furthermore, we implement some principles of colloidal and interfacial science to discuss the critical role of cellulose binding in the aforesaid fields. Even though the CN facets covered in this study by no means encompass the great amount of literature available, they may be regarded as the basis for future developments in the binder applications of these highly desirable materials.

HighlightsPreparation strategies of cellulose nanopaper were elaborated.Functionalization of cellulose nanopaper and its advanced applications were summarized.Prospects and challenges of cellulose nanopaper were discussed.Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices, food packaging, biomedical application, and so forth, owing to their various advantages such as good flexibility, tunable light transmittance, high thermal stability, low thermal expansion coefficient, and superior mechanical properties. Herein, recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies. We begin with a brief introduction of the three types of nanocellulose: cellulose nanocrystals, cellulose nanofibrils and bacterial cellulose, recapitulating their differences in preparation and properties. Then, the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared. Furthermore, the advanced applications of cellulose nanopaper including energy storage, electronic devices, water treatment, and high-performance packaging materials were highlighted. Finally, the prospects and ongoing challenges of cellulose nanopaper were summarized.

In this study, bamboo fibers and parenchyma cells were separated by a physical water-medium method. To compare the characteristics of nanofibrils from these two types of cells, lignocellulose nanofibrils (LCNFs) and cellulose nanofibrils (CNFs) were prepared by different processes. Atomic force microscopy analysis revealed that both fibers and parenchyma cells can be separated into individual fibrils after grinding three times. However, LCNFs had a diameter of 20–40 nm, which was larger than that of CNFs (10–20 nm). Additionally, the films prepared from LCNFs had lower tensile strength, but higher hydrophobicity compared with those from CNFs. X-ray diffraction analysis and tensile test of the films showed that the nanofibrils isolated from fibers and parenchyma cells had similar crystallinity and mechanical properties. This study shows a promising application of bamboo parenchyma cells, which are usually discarded as waste in the processing of bamboo products, in the preparation of nanofibers.

The use of wood-derived cellulose nanofibrils (CNFs) or galactoglucomannans (GGM) for emulsion stabilization may be a way to obtain new environmentally friendly emulsifiers. Both have previously been shown to act as emulsifiers, offering physical, and in the case of GGM, oxidative stability to the emulsions. Oil-in-water emulsions were prepared using highly charged (1352 ± 5 µmol/g) CNFs prepared by TEMPO-mediated oxidation, or a coarser commercial CNF, less charged (≈ 70 µmol/g) quality (Exilva forte), and the physical emulsion stability was evaluated by use of droplet size distributions, micrographs and visual appearance. The highly charged, finely fibrillated CNFs stabilized the emulsions more effectively than the coarser, lower charged CNFs, probably due to higher electrostatic repulsions between the fibrils, and a higher surface coverage of the oil droplets due to thinner fibrils. At a constant CNF/oil ratio, the lowest CNF and oil concentration of 0.01 wt % CNFs and 5 wt % oil gave the most stable emulsion, with good stability toward coalescence, but not towards creaming. GGM (0.5 or 1.0 wt %) stabilized emulsions (5 wt % oil) showed no creaming behavior, but a clear bimodal distribution with some destabilization over the storage time of 1 month. Combinations of CNFs and GGM for stabilization of emulsions with 5 wt % oil, provided good stability towards creaming and a slower emulsion destabilization than for GGM alone. GGM could also improve the stability towards oxidation by delaying the initiation of lipid oxidation. Use of CNFs and combinations of GGM and CNFs can thus be away to obtain stable emulsions, such as mayonnaise and beverage emulsions.

Cellulose nanofibrils (CNFs) have been widely used as a nanofiller for polymer composite reinforcement due to their excellent mechanical properties. However, CNF is produced in water and needs to be dried prior to use in composite materials. The presence of hydroxyl groups on the surface of CNF creates strong hydrogen bonding that makes it difficult and costly to dry. Additionally, the hydrophilicity at the fiber surface results in agglomeration of CNFs within many polymer matrices. In this study, chitosan (CS) was co-precipitated with CNF to produce a dual-bonding filler for use in poly (lactic acid) (PLA) composites. CS promotes improved interfacial interaction within the polymer matrix by forming strong hydrogen bonds with the CNF and potential covalent bonds with the PLA. The results confirmed that the addition of a small amount of CS significantly improved the mechanical properties compared to PLA + CNF composites and neat PLA. The detailed study of the PLA + CNF/CS composites reveals the synergetic effect of the hydrogen and covalent bonding mechanism for PLA reinforcement. Graphical abstract

Photoelectrocatalytic (PEC) technologies provide a promising and sustainable approach for the elimination of persistent organic pollutants, but their practical deployment is limited by catalyst deactivation and metal leaching. Here, we proposed a rational design strategy to address this challenge by constructing a rigid-flexible dual network hydrogel photoelectrode (CCMPCu) for ultrafast and stable catalytic degradation of bisphenol A (BPA) with minimal metal leaching. CCMPCu was fabricated by incorporating Cu2O@ZIF-67 into a chemically cross-linked chitosan/cellulose nanofibril (CNF)-MXene matrix (rigid network), which was further embedded within an in situ polymerized polyaniline network (flexible network). CCMPCu exhibited a high BPA adsorption capacity of 211.1 ± 6.2 mg g−1, ∼4 × that of Cu2O@ZIF-67. Under visible light, CCMPCu achieved nearly complete BPA removal (∼100%) within 40 min, with a pseudo-first-order rate constant (k = 0.0836 ± 0.0041 min−1), representing a ninefold enhancement over Cu2O@ZIF-67. CCMPCu also showed excellent durability, maintaining over 90% removal efficiency after ten consecutive cycles with negligible Cu (<5 ppb) and Co (<8 ppb) leaching. Mechanistic studies revealed that synergistic integration of the rigid-flexible dual network, MXene, and Cu2O@ZIF-67 facilitated pollutant preconcentration and photogenerated charge separation, thereby collectively contributing to the enhanced PEC performance. Additionally, CCMPCu showed broad applicability by effectively degrading structurally diverse bisphenol analogues. This work presents a generalizable strategy for fabricating robust, multifunctional CS/CNF-based hydrogel photoelectrodes and offers valuable insights for the sustainable remediation of endocrine-disrupting contaminants. CCMPCu, a chitosan/CNF-MXene/polyaniline hydrogel photoelectrode embedding Cu2O@ZIF-67, preconcentrates pollutants and enhances charge separation, achieving ∼100 % BPA removal in 40 min (k = 0.0836 min−1) under visible light, with < 5 ppb Cu leaching over 10 cycles and broad bisphenol applicability. [Display omitted] •Dual-network hydrogel photoelectrode achieves ultrafast PEC degradation of BPA.•Delivers ≈9 × faster kinetics than Cu2O@ZIF-67; ∼100 % BPA removal within 40 min.•Exceptional BPA adsorption capacity (211.1 mg g−1) via multivalent interactions.•Retains > 90 % efficiency after 10 cycles; negligible leaching (Cu < 5 ppb, Co < 8 ppb).•Broad scope: effective against structurally diverse bisphenol analogues.

In this study, cellulose nanofibers (CNF) were obtained by chemical pretreatment using a rubberwood substrate. Different forms of drying were used to prepare three CNF film variants. Each of the films was rehydrated and hot-pressed to introduce more hydrogen bonds, and the films were characterized in terms of density and porosity, micromorphology, and mechanical properties. The mechanical properties of the films improved substantially after rehydration and hot-press drying. The tensile strengths of the films increased to approximately two to three times that of the original CNF films. These results with micromorphological observations suggest that adjusting the water content during CNF drying can significantly improve the formation of 3D networks in the films, thus imparting higher hydrogen bonding content to the films and improving the mechanical properties of the substrates. This study provides a theoretical basis for the formation of high-strength materials through water molecule-induced assembly and broadens the application of biomass cellulose materials in emerging fields.