Cellulose Nanofibers Research Articles

Direct ink writing 3D printed graphene oxide nanocomposite aerogel for intelligent fire-warning and exceptional fire-shielding

Fabricating intelligent fire-warning sensors with controllable 3D structures and shapes by advanced manufacturing technology is a formidable challenge but remains the critical factor in broadening fire prevention and protection. Herein, the novel fire-warning aerogel with a high-fidelity 3D porous structure and diversiform geometrical features based on graphene oxide (GO), cellulose nanofiber (CNF) and ammonium polyphosphate (APP) was fabricated via direct ink writing (DIW) 3D printing combined with freeze-drying technology. Benefiting from the hydrogen bonding multi-interactions between the molecules as well as the ideal rheological properties, the ink containing 20 wt% of CNF (GA-CNF-20) had a dynamic yield stress of 620 Pa. As a result, the corresponding aerogel had a significantly improved elasticity modulus of 153 kPa and a compressive stress of 400 kPa at a deformation of 39.7 %. Meanwhile, GA-CNF-20 displayed an ultrafast fire-warning trigger time (1.32 s) and a long-term response time (170 s) because of the thermal reduction property of GO together with the in-situ phosphorus doping reaction of APP under fire. Besides, the GA-CNF-20 also exhibited a strong heat-insulating capability, high char-forming property, self-extinguishing performance as well as structure integrity in the burning test. The relevant improvement mechanisms were attributed to the non-flammable gas diluting effect, intumescent char layer barrier effect and fire blowing-out effect in both gas and condensed phases. Such self-supporting printed aerogel can potentially be used as a fire-warning sensor for designated systems with specific precision structure in multi-domains of electrical and traffic engineering.

Study on the neurotoxicity of the temephos impregnated kenaf cellulose nanofiber (KCNF+T) aerosols against the female Aedes aegypti mosquitoes

Study on the neurotoxicity of the temephos impregnated kenaf cellulose nanofiber (KCNF+T) aerosols against the female Aedes aegypti mosquitoes

Sintesis dan Karakterisasi Solid Polymer Electrolyte (SPE) Berbasis Nanofiber Selulosa untuk Menunjang Baterai Litium Berdensitas Tinggi dan Ramah Lingkungan

Lithium battery as one of the energy storage has two important elements, namely electrodes and electrolyte. Electrolyte is a part of the battery element that has undergone many developments. In this study, the manufacture of electrolytes in the form of Solid Polymer Electrolyte (SPE) was carried out by utilizing the abundant availability of nata de coco. The nanofibrous cellulose structure in Bacterial Cellulose (BC) nata de coco has the advantages of good porosity, flexibility in surface functionality, compact porous structure that provides abundant ion pathways and hetero atoms (oxygen atoms) with free electron pairs that facilitate ionic conduction. The SPE synthesis process was carried out by varying the soaking time of nata de coco in ethanol, namely 1, 2 and 3 days to determine the structure with optimal results. FTIR characterization results show the synthesis of cellulose nanofiber has the same groups as commercial cellulose groups in the form of O-H, C-H, C=O and C-O. CV characterization results show the SPE electrolyte has good redox properties, especially in the 2-day variation with the highest specific capacitance. The EIS test showed the lowest resistance in the 1-day variation sample with a conductivity of 0.017 ohm-1.

Lignin-modified cellulose nanofibers hydrogel under adjustable binary solvent systems with excellent adhesion, self-healing and anti-freeze properties

Hydrogels with remarkable flexibility have gained popularity as materials for current research. However, the unfavorable properties of short-term adhesion, susceptibility to damage, and freezing in low-temperature presented by conventional hydrogels have become bottlenecks for further applications. In this work, an anti-freezing hydrogel with excellent mechanical, adhesion, and self-healing properties were developed by constructing a persistent semiquinone/quinone-catechol redox equilibrium environment. The introduction of lignin-modified cellulose nanofibers (LCNFs) significantly improved the overall mechanical properties of the material, driven by strong hydrogen bond interactions. This enhancement was evident in the tensile properties (97.74 ± 1.72 kPa, 783 %) and compression properties (> 90 %). Within the internal network of the gel, the synergistic action of lignin and ammonium persulfate resulted in the production of catechol, which imparted the gel with excellent adhesion properties (28.26 ± 2.13 KPa) and broad adhesion applicability. In addition, the incorporation of ethylene glycol (EG) positively contributed to the strengthening of the gel while endowed with tunable anti-freezing properties. Given the exceptional advantages of the prepared hydrogels, they were used to assemble flexible strain sensors with outstanding sensitivity for monitoring human motions.

Poly-dopamine coated-cellulose/chitosan hybrid carbon aerogel composite phase change materials with efficient photothermal conversion and storage

Solar energy, being both low-cost and renewable, is a viable alternative for thermal storage and can help mitigate the energy crisis. Efficient conversion and storage for solar energy can significantly enhance energy utilization. Phase change materials (PCMs), such as paraffin (PW), are capable of harvesting and converting solar energy into thermal energy, thus playing a crucial role in solar energy utilization. However, PW faces challenges, such as solid–liquid leakage and low photothermal conversion efficiency, which hinder its applications in solar energy storage. In this study, we proposed the construction of a robust poly-dopamine (PDA)/chitosan (CS)/cellulose nanofibers (CNF) carbon aerogel with enhanced photothermal performance. This is achieved by incorporating PDA, known for its excellent light absorption properties, and cross-linking it with low-cost biomass CS and CNF via a Schiff base reaction. The resulting novel composite PCMs exhibit high photothermal conversion efficiency and shape stability by encapsulating PW within the PDA/CS/CNF carbon aerogel. Our findings demonstrate that the composite PCMs have a high melting energy-storage capacity of 209.57 J/g. Notably, the introduction of PDA significantly improved the photothermal conversion efficiency by 94.9 %. These results suggest that composite PCMs hold great potential for applications in photothermal energy conversion and storage.

Bioinspired Homonuclear Diatomic Iron Active Site Regulation for Efficient Antifouling Osmotic Energy Conversion.

Membrane-based reverse electrodialysis is globally recognized as a promising technology for harnessing osmotic energy. However, its practical application is greatly restricted by the poor anti-fouling ability of existing membrane materials. Inspired by the structural and functional models of natural cytochrome c oxidases (CcO), the first use of atomically precise homonuclear diatomic iron composites as high-performance osmotic energy conversion membranes with excellent anti-fouling ability is demonstrated. Through rational tuning of the atomic configuration of the diatomic iron sites, the oxidase-like activity can be precisely tailored, leading to the augmentation of ion throughput and anti-fouling capacity. Composite membranes featuring direct Fe-Fe motif configurations embedded within cellulose nanofibers (CNF/Fe-DACs-P) surpass state-of-the-art CNF-based membranes with power densities of ca. 6.7Wm-2 and a 44.5-fold enhancement in antimicrobial performance. Combined, experimental characterization and density functional theory simulations reveal that homonuclear diatomic iron sites with metal-metal interactions can achieve ideally balanced adsorption and desorption of intermediates, thus realizing superior oxidase-like activity, enhanced ionic flux, and excellent antibacterial activity.

Efficient mercury ion abatement through highly porous cellulose nanofibrils combined with microporous organic polymer enhancements

Pristine microporous organic polymer (p-MOP), owing to the presence of heteroatoms, has emerged as a significant platform for sensing and adsorption of heavy metal ions. The present work is a novel approach for developing highly porous hybrid architectures with trimesic acid and phenylene diamine-based p-MOP embedded over rice straw-derived cellulose nanofibers (ACNFs/MOP) for the sensing and remediation of mercury ions in the aqueous medium. The ACNFs/MOP were successfully characterized by various techniques, such as FTIR spectroscopy, BET surface area analysis, X-ray diffraction, XPS, HR-TEM, and TGA. The hybrid exhibited excellent porosity and crystallinity. The ACNFs/MOP hybrid was highly selective for Hg(II) ions, displaying substantial enhancement in fluorescence intensity with an LOD of 3.927 nM while also facilitating simultaneous adsorption. The adsorption showed a strong fit with pseudo-second-order kinetics and Langmuir isotherm models with an excellent adsorption capacity of 416.18 mg g−1, attributed to electrostatic interactions, coordination surface complexation, and metal-π interactions, as confirmed by XPS studies. Thermodynamic studies indicated an endothermic adsorption process. Box-Behnken Design-Response Surface methodology with Design Expert Software-13 was applied to model the process parameters. The hybrids were 97 % efficient even after five cycles of reusability, exhibiting their excellent potential for removing perilous Hg(II) ions from wastewater.

Recyclability of wastepaper containing cellulose nanofibers

Cellulosic/lignocellulosic nanofibers (CNF/LCNF) are value-added products which recently have been considered widely. This study focused on valorization of waste by making CNF from white cutting wastepaper (WCW), which was confirmed by the transmission electron microscope images. The CNF present in the paper recycling process showed significant effects on the final product and process aspects. Addition of 5% CNF (based on dry weight of pulp) to the recycled fibers improved the strength properties as well as the fines retention. But in contrast, the drainage decreased from 303 to 188 mL CSF. Finally, considering the importance of wastepaper history on the quality of recycling process and final products, as a new vision, this study focused on recyclability of wastepaper which has experienced CNF as an additive in their history of papermaking. In this respect, the papers reinforced with nanofibers in their history, after several recycling, experienced less reduction in the tensile and tear indices and fines retention. In summary, it seems that the presence of CNF in the wastepaper can slow down the reduction of product density and process properties during several recycling cycles and so restore their potential for subsequent papermaking cycles.

Methods for Fabrication of Self/Free Standing Nanocellulose (NC)-Nano Montmorillonite (N-MMT) Composite Films/Sheets — A Review

Plastic pollution looms large as a formidable foe to the environment. Enter cellulose nanofibers, the shining stars in the quest for innovative, eco-friendly paper-based packaging that is not just renewable, but also recyclable and biodegradable. These cellulose wonders boast impressively low oxygen permeability, but when it comes to water vapor, they fall short compared to traditional packaging plastics like LDPE. To tackle this challenge, researchers have been crafting composites by blending cellulose nanofibers with inorganic nanoparticles, such as Montmorillonite clay, which helps to curb water vapor permeability. However, this clever addition comes with a catch — it further complicates the already tricky drainage process during layer formation via vacuum filtration. This review delves into the complex world of nano cellulose-nano-MMT (Montmorillonite) composites, examining their preparation processes, unique characteristics, wide-ranging uses, and their significant contribution to promoting circular economy principles. By combining cellulose nanomaterials with MMT, a synergistic approach is taken to develop a new composite material with improved mechanical, thermal, and barrier properties. Various fabrication techniques are explored, including solution blending, in-situ polymerization, and electrospinning, allowing for customized design and optimization of the composite material. The review discusses how the nano cellulose-MMT composite demonstrates enhanced mechanical strength, thermal stability, and barrier properties, positioning it as a sustainable option compared to traditional materials. The review also showcases the diverse applications of these nano-composites in fields like packaging, biomedical devices, and environmental cleanup, emphasizing their alignment with circular economy principles. By examining the entire life cycle of these composites, from production to use and eventual disposal or recycling, the review underscores their role in supporting a circular economy. In light of the ongoing efforts by the scientific community and various industries to identify environmentally sustainable solutions, it is imperative to comprehend the synthesis, properties, and applications of nano cellulose-MMT composites. This understanding is essential for advancing sustainable processing for green material development.

Myelin Sheath-Inspired Hydrogel Electrode for Artificial Skin and Physiological Monitoring.

Significant advancements in hydrogel-based epidermal electrodes have been made in recent years. However, inherent limitations, such as adaptability, adhesion, and conductivity, have presented challenges, thereby limiting the sensitivity, signal-to-noise ratio (SNR), and stability of the physiological-electrode interface. In this study, we propose the concept of myelin sheath-inspired hydrogel epidermal electronics by incorporating numerous interpenetrating core-sheath-structured conductive nanofibers within a physically cross-linked polyelectrolyte network. Poly(3,4-ethylenedioxythiophene)-coated sulfonated cellulose nanofibers (PEDOT:SCNFs) are synthesized through a simple solvent-catalyzed sulfonation process, followed by oxidative self-polymerization and ionic liquid (IL) shielding steps, achieving a low electrochemical impedance of 42 Ω. The physical associations within the composite hydrogel network include complexation, electrostatic forces, hydrogen bonding, π-π stacking, hydrophobic interaction, and weak entanglements. These properties confer the hydrogel with high stretchability (770%), superconformability, self-adhesion (28 kPa on pigskin), and self-healing capabilities. By simulating the saltatory propagation effect of the nodes of Ranvier in the nervous system, the biomimetic hydrogel establishes high-fidelity epidermal electronic interfaces, offering benefits such as low interfacial contact impedance, significantly increased SNR (30 dB), as well as large-scale sensor array integration. The advanced biomimetic hydrogel holds tremendous potential for applications in electronic skin (e-skin), human-machine interfaces (HMIs), and healthcare assessment devices.

Application of Anionic Hydrogels from Date Palm Waste for Dye Adsorption in Wastewater Treatment.

This work aimed to develop an anionic cellulose nanofiber (CNF) bio-adsorbent from date palm tree waste and to investigate its removal efficiency compared to cationic methylene blue dye from contaminated water. Date palm pulp was first prepared from date palm leaves through acid hydrolysis using H2SO4, followed by hydrolysis in a basic medium using KOH, in which the process completely removed the components of hemicellulose, lignin, and silica. To obtain anionic CNF, the resulting pulp was further treated with H2SO4, followed by centrifugation. Biogel formation of the CNF suspension was promoted by sonication, where its removal efficiency of methylene blue dye was studied as a function of dye concentration, temperature, contact time, and pH value. In this work, we investigated two isotherms, i.e., Langmuir and Freundlich. The Langmuir model's consistency with the experimental data suggests that the adsorption of methylene blue dye onto CNF is monolayer and surface-limited. The reported maximum removal efficiency of 5 mg/g at 60 °C indicates the optimal temperature for adsorption in this specific case. Additionally, a pseudo-second-order model and Elovich model were also utilized to obtain a better understanding of the adsorption mechanism, in which we found not just physical adsorption but also an indication of a chemical reaction occurring between methylene blue dye and CNF. According to the results, that pseudo-second-order model's consistency with the experimental data suggests that the adsorption of methylene blue (MB) onto CNF is rate-limiting step involving chemisorption between the two. The study reveals that CNF adsorbents derived from renewable natural waste sources such as date palm leaves can be effective in removing cationic contaminants such as methylene blue dye.

Nanostructured Affinity Membrane to Isolate Extracellular Vesicles from Body Fluids for Diagnostics and Regenerative Medicine.

Electrospun regenerated cellulose (RC) nanofiber membranes were prepared starting from cellulose acetate (CA) with different degrees of substitution. The process was optimized to obtain continuous and uniformly sized CA fibers. After electrospinning, the CA membranes were heat-treated to increase their tensile strength before deacetylation to obtain regenerated cellulose (RC). Affinity membranes were obtained by functionalization, exploiting the hydroxyl groups on the cellulose backbone. 1,4-Butanediol-diglycidyl ether was used to introduce epoxy groups onto the membrane, which was further bioconjugated with the anti-CD63 antibody targeting the tetraspanin CD63 on the extracellular vesicle membrane surface. The highest ligand density was obtained with an anti-CD63 antibody concentration of 6.4 µg/mL when bioconjugation was performed in carbonate buffer. The resulting affinity membrane was tested for the adsorption of extracellular vesicles (EVs) from human platelet lysate, yielding a very promising binding capacity above 10 mg/mL and demonstrating the suitability of this approach.

Enhancing emulsion stability and adsorption of Pickering emulsions using alkylated cellulose nanofibers

Cellulose nanofibers (CNFs) extracted from plant cell walls form a three-dimensional network in water and stabilize the dispersion of droplets, which are used as emulsion stabilizers. In this study, four types of alkyl-grafted CNFs (ACNFs) with different lengths of dialkyl chains (diC4, diC6, diC8, and diC10) were synthesized by the surface modification of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized CNF (TOCNF) to improve the stability of oil-in-water Pickering emulsions (PEs). The ACNF-stabilized emulsions with a 20/80 ratio of oil/water were prepared using two different oils (olive oil and eucalyptus oil) and the ACNF 1.0 % dispersion, and the changes over time were investigated at approximately 25 °C. Compared to TOCNF, the ACNFs provided more stable olive oil-PE (o-PE) and eucalyptus oil-PE (e-PE) although the stabilization behaviors of o-PE and e-PE differed. Olive oil, which contained rich long-chain fatty acids, was more likely to interact with the ACNFs, thereby promoting the interfacial adsorption of oil droplets. On the other hand, eucalyptus oil is mainly composed of 1,8-cineole and does not have alkyl chains, so the interaction with the ACNFs was weak and therefore, sufficient interfacial adsorption could not be obtained. The results of the particle size distribution and viscosity measurements also showed that the ACNFs contributed significantly to the stabilization of o-PE. Based on the overall experimental results, it was determined that the diC6-ACNF gave the most significant stability improvement. Therefore, we designed an alkylated CNF that mimics diC6-ACNF for MD simulations. MD simulations showed that hydrophobic modification created a hydrophobic interaction between the alkyl chain and dodecane molecules as the oil, leading to the enhancing adsorption of ACNF at the oil droplet interfaces.

Base-free trifluoroacetylation: From methyl glucopyranoside to cellulose nanofibers

Trifluoroacetic anhydride (TFAA) reacts smoothly with low molecular weight carbohydrates and cellulose nanofibers (CNFs) under base-free conditions. Methyl α- and β-d-glucopyranoside were used as model compounds to optimize reaction conditions, which were then applied to lyophilized CNFs for surface modification. ATR-IR spectroscopy and powder X-ray diffraction were employed to characterize the modified CNFs. Trifluoroacetylation for 4 h yields a degree of substitution (DS) of 0.4 acyl groups per anhydroglucose unit while maintaining a crystallinity index near 50 %. DS values were quantified by gravimetry, acid–base titration after saponification, and a novel approach utilizing solution 19F NMR spectroscopy which offers greater accuracy than the other techniques. This study presents an efficient, base-free method for derivatizing carbohydrates as well as surface functionalization of CNFs with trifluoroacetyl groups, potentially expanding their application in fiber-reinforced thermoplastic composites.

Shelf-life extension of pomegranate arils using banana powder-based nanocomposite coatings functionalized with cellulose nanofiber and zinc-oxide nanoparticles

ABSTRACT This study explored a novel nanocomposite comprising banana powder (BP), cellulose nanofiber (CNF), and 0.6% zinc oxide nanoparticles (ZnO NPs). The treatment involved immersing arils in the respective nanocomposite coatings for 4 min, followed by air-drying at room temperature (25°C) and subsequent storage in polyethylene terephthalate punnets at 4°C and 85% relative humidity for 21 d. Results demonstrated that the nanocomposites significantly (p < .05) reduced total plate and yeast counts, delayed colour and texture degradation, and decreased weight loss and respiration rates while maintaining levels of total soluble solids and titratable acidity compared to the control (water) and standard BP/CNF treatment. The BP/CNF/ZnO-PPW was more effective as it displayed a lower respiration rate (50 mL CO2 kg−1 h −1), weight loss (0.4%), and maintained higher firmness (12.4 N) compared to the control treatment. Overall, the nanocomposite treatments with ZnO NPs resulted in a 6-day shelf-life extension, offering a promising solution through nanotechnology applications.

Impact of deep eutectic solvent pre-treatment on the extraction of cellulose nanofibers

Deep Eutectic Solvents (DESs) have emerged as promising eco-friendly pre-treatment agents for lignocellulosic biomass, offering considerable advantages for the nanofibrillation process. This study investigates the impact of DESs on cellulose fibers morphology, focusing on solubilization phenomena in the amorphous regions that may facilitate cellulose nanofiber production. The pre-treatment process combining a DES (triethylmethylammonium chloride and imidazole, TEMA:IMD) with microwave (MW) energy was optimized to enhance the solubility of cellulosic fibers. A response surface methodology (RSM) was employed to optimize the DES-MW-assisted pre-treatment. Results show that the reaction time and the temperature significantly influence the solubility of cellulosic fibers. The optimized conditions resulted in cellulose fibers with low content of hemicellulose and lignin, high crystallinity index, and improved thermal stability. The effectiveness of DES-MW pre-treatment in producing cellulose nanofibers (CNFs) from native and pre-treated fibers was investigated. Cellulose fibers pre-treated with a DES yielded CNFs with a narrower diameter distribution. Overall, optimized DES-MW pre-treatment offers a promising strategy for the efficient and sustainable extraction of CNFs.

Composite edible film mimicking cell wall based on arabinoxylan, β-glucan and nanocellulose: Microstructural, physico-chemical properties, and preservation effect

To achieve sustainable environmental development, various biodegradable films have been designed to replace plastic films. The cell walls of the wheat bran aleurone layers primarily comprise alternately overlapping arabinoxylan (AX), β-glucan (BG) and small quantities of cellulose and ferulic acid. The differences in their composition can affect their mechanical strength and hydration. Therefore, multilayer films of AX, BG, cellulose nanofibers (CNFs), and free ferulic acid were prepared to simulate the cell walls of wheat aleurone layers, and the effect of different CNF contents on cell walls characteristics was investigated. The microstructure, physical properties, and hydration characteristics of multilayer films were studied using scanning electron microscopy, time-domain nuclear magnetic resonance, and thermogravimetric analysis. The AX/BG/8%CNF multilayer films possessed excellent thermal stability and mechanical properties along with slow moisture diffusion and flowability. When the CNF content within the films was 8%, the polymer composite structure hindered the diffusion of moisture. Inspired by the biological effects of wheat grain cell walls, cellulose multilayer films were used for blueberries preservation, and the decay rate, weight loss index, and respiration rate of blueberries were found to decrease significantly.

Cellulose nanofibers/liquid metal hydrogels with high tensile strength, environmental adaptability and electromagnetic shielding for temperature monitoring and strain sensors

Hydrogel sensors are widely recognized in the fields of flexible electronics and human motion monitoring due to their multiple properties and potential applications. However, how to prepare hydrogels with multiple excellent properties simultaneously and how to improve the compatibility of conductive fillers with hydrogel matrices remain a major challenge. Therefore, in this work, liquid metal (LM) droplets stabilized by cellulose nanofibers (CNFs) were utilized to initiate the polymerization of acrylamide monomer (Am), which was used as a conductive filler. Meanwhile, reduced graphene oxide (rGO) was introduced to bridge the LM droplets. The hydrogels were then further crosslinked in glycerol. The constructed CNF@LM/polyacrylamide/rGO/gelatin/glycerol hydrogel possesses high tensile properties (>1317 %), high environmental adaptability (−80 to 80 °C), and adhesion properties for multifunctional sensing. What's more, it offers the high sensitivity of both a strain sensor and a temperature sensor for accurate monitoring of human movement at room temperature and even in extreme environments. In addition, this hydrogel has excellent electromagnetic shielding properties and antimicrobial properties. This research opens up a new direction for the preparation of multifunctional hydrogel sensors, expanding their applications in cutting-edge fields such as temperature monitoring, wearable smart devices, e-skin and intelligent robotics.

Polyion Hydrogels of Polymeric and Nanofibrous Carboxymethyl Cellulose and Chitosan: Mechanical Characteristics and Potential Use in Environmental Remediation.

Recently, cellulose and other biomass nanofibers (NFs) have been increasingly utilized in the design of sustainable materials for environmental, biomedical, and other applications. However, the past literature lacks a comparison of the macromolecular and nanofibrous states of biopolymers in various materials, and the advantages and limitations of using nanofibers (NF) instead of conventional polymers are poorly understood. To address this question, hydrogels based on interpolyelectrolyte complexes (IPECs) between carboxymethyl cellulose nanofibers (CMCNFs) and chitosan (CS) were prepared by ele+ctrostatic cross-linking and compared with the hydrogels of carboxymethyl cellulose (CMC) and CS biopolymers. The presence of the rigid CMCNF altered the mechanism of the IPEC assembly and drastically affected the structure of IPEC hydrogels. The swelling ratios of CMCNF-CS hydrogels of ca. 40% were notably lower than the ca. 100-300% swelling of CMC-CS hydrogels. The rheological measurements revealed a higher storage modulus (G') of the CMCNF-CS hydrogel, reaching 13.3 kPa compared to only 3.5 kPa measured for the CMC-CS hydrogel. Further comparison of the adsorption characteristics of the CMCNF-CS and CMC-CS hydrogels toward Cu2+, Cd2+, and Hg2+ ions showed the slightly higher adsorption capacity of CMC-CS for Cu2+ but similar adsorption capacities for Cd2+ and Hg2+. The adsorption kinetics obeyed the pseudo-second-order adsorption model in both cases. Overall, while the replacement of CMC with CMCNF in hydrogel does not significantly affect the performance of such systems as adsorbents, CMCNF imparts IPEC hydrogel with higher stiffness and a frequency-independent loss (G″) modulus and suppresses the hydrogel swelling, so can be beneficial in practical applications that require stable performance under various dynamic conditions.

Covalent and non‐covalent action‐enhanced cellulose‐based thermally conductive composite (TCC) films fabricated via vacuum‐assisted self assembly with high thermally conductivity and superior mechanical performance

AbstractAs is known, to establish covalent or non‐covalent interaction between filler and matrix, which helps to reduce the interface thermal resistance (ITR) as well as construct good thermal conduction channels, is a good strategy for dealing with the risk of thermal runaway in the extreme service environment of electronic equipment. In this paper, carboxylated nanocellulose fiber (c‐CNF) was used as matrix, and a hybrid filler (M‐CoNPs@GNP) was fabricated by coating cobalt‐nanoparticles (CoNPs) and grafting maleimide on graphene nanosheets (GNPs). M‐CoNPs@GNP/c‐CNF thermally conductive composite (TCC) films were successfully fabricated by combining with c‐CNF. As zero‐dimensional particles, CoNPs can effectively prevent GNPs agglomeration due to surface effects, and “‐NH” in maleimide dehydrates with “‐COOH” in c‐CNF to form “C‐N‐C” covalent bonds, with strong hydrogen bond formed between filler and matrix, which remarkably enhances the interface compatibility between matrix and filler. The ITR has been reduced to form a well‐defined three‐dimensional thermal conduction path, achieving an ultra‐high in‐plane TC (35.9 W·m−1·K−1) for MCGC40, which is 7.9 times that of pure c‐CNF film, in addition to a sufficiently high tensile strength of 123.3 MPa. The combination of high in‐plane TC, excellent mechanical flexibility and good electrical insulation jointly justifies the potential application of M‐CoNPs@GNP/c‐CNF TCC films in effective thermal management of flexible electronic products.Highlights CoNPs effectively inhibit GNPs agglomeration. GNPs exhibit hydrophilicity after modification. Modified fillers interact fairly well with the matrix. High tensile strength and exceptional flexibility are achieved. TCC films exhibit both electrical insulation and hydrophobicity.