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Nanocellulose, as a nanoscale polymer material, has garnered significant attention worldwide due to its numerous advantages including excellent biocompatibility, thermal stability, non-toxicity, large specific surface area, and good hydrophilicity. Various methods can be employed for the preparation of nanocellulose. Traditional approaches such as mechanical, chemical, and biological methods possess their own distinct characteristics and limitations. However, with the growing deterioration of our living environment, several green and environmentally friendly preparation techniques have emerged. These novel approaches adopt eco-friendly technologies or employ green reagents to achieve environmental sustainability. Simultaneously, there is a current research focus on optimizing traditional nanocellulose preparation methods while addressing their inherent drawbacks. The combination of mechanical and chemical methods compensates for the limitations associated with using either method alone. Nanocellulose is widely used in wound dressings owing to its exceptional properties, which can accelerate the wound healing process and reduce patient discomfort. In this paper, the principle, advantages and disadvantages of each preparation method of nanocellulose and the research findings in recent years are introduced Moreover, this review provides an overview of the utilization of nanocellulose in wound dressing applications. Finally, the prospective trends in its development alongside corresponding preparation techniques are discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Nanocellulose aerogel has the advantages of porosity, low density and high specific surface area, which can effectively realize the adsorption and treatment of wastewater waste gas. The methods of preparing nanocellulose mainly include mechanical, chemical and biological methods. Nanocellulose is formed into nanocellulose aerogel after gelation, solvent replacement and drying processes. Based on the advantages of easy modification of nanocellulose aerogels, nanocellulose aerogels can be functionalized with conductive fillers, reinforcing fillers and other materials to give nanocellulose aerogels in electrical, mechanical and other properties. Through functionalization, the properties of nanocellulose composite aerogel such as hydrophobicity and adsorption are improved, and the aerogel is endowed with the ability of electrical conductivity and electromagnetic shielding. Through functionalization, the applicability and general applicability of nanocellulose composite aerogel in the field of environmental protection are improved. In this paper, the preparation and functional modification methods of nanocellulose aerogels are reviewed, and the application prospects of nanocellulose composite aerogels in common environmental protection fields such as dye adsorption, heavy metal ion adsorption, gas adsorption, electromagnetic shielding, and oil-water separation are specifically reviewed, and new solutions are proposed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Wooden building materials have advantages in terms of biodegradability, non-toxicity, pollution-free and recycling. Currently, applications of natural wood are extremely limited because of low density, low strength and toughness. Therefore, we reported an effective modification strategy with nano-scale cellulose nanofibrils design to prepare a synergistically enhanced cellulosic material. Via three steps: i) the secondary alcohol hydroxyl groups in C 2 , C 3 position were cut; ii) oxidize the hydroxyl group at C 2 , C 3 position to achieve dialdehyde cellulose; and iii) oxidized again to obtain dicarboxylic cellulose. Subsequently, thanks to the regulation of the average moisture content, the moisture content in the wood surface and subsurface increased in a short time. The wood softening layer contributes to the hotpressing treatment of the wood. The mechanical properties and dimensionality have been greatly improved. The obtained delignified oxidated hot-pressed wood with 0.55 mmol/g carboxyl group content demonstrates excellent strength of 328.8 ± 7.43 MPa and Young's modulus of 8.1 ± 0.14 GPa, which is twice than that of natural wood. Delignified oxidated hot-pressed wood also shows exceptional toughness of 8.3 ± 0.28 MJ/m 3 . Other than that, the shore hardness indicates 0.55 mmol/g carboxylic group, which could increase the hardness at the wood surface hardness to 72.5 ± 4.29°., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Holocellulose nanofibrils (HCNFs) are nanoscale objects extracted from biomass resources and have attracted attention as sustainable building blocks for nanomaterials. In this study, we report a top-down approach for extracting HCNFs from manau rattan that involves pulping, bleaching and TEMPO oxidation. The extracted HCNFs showed a uniform width of around 18.5 nm and a length of a few micrometers, high crystallinity (66.5 %), and good thermal stability (302 °C). The extracted HCNFs were used to fabricate HCNF film via vacuum filtration and drying (air drying and solvent exchange drying). Surprisingly, the HCNF film fabricated by solvent exchange drying (HCNF-film SD ) simultaneously presented a high total transmittance (93.7 %) and high haze (62.2 %), and its total transmittance was even higher than that of glass. The resulting HCNF-film SD displayed a high tensile strength (84.8 MPa), Young's modulus (3.7 GPa), and toughness (1.4 MJ m -3 ), making it a high-performance and eco-friendly film for applications in precision optoelectronics and aerospace materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Designing intertwined porous structure is highly desirable to improve the electrochemical performance of carbon materials for supercapacitor. In this contribution, three-dimensional (3D) carbonized polyimide/cellulose (CPC) composite is fabricated via a facile "one-step" carbonization, in which cellulose as cross-linked agent is capable of modulating the molecular structure of polyamic acid, thus ensuring the formation of intertwined porous networks in the obtained carbon skeleton. Benefitting from the high specific surface area (951 m 2 g -1 ) and uniformly distributed pores, the optimized CPC-5 electrode exhibits an outstanding specific capacitance of 300F g -1 in 6.0 M KOH electrolyte. More impressively, the CPC-5 based symmetrical supercapacitor affords a high energy density of 22.6 Wh kg -1 at power density of 800 W kg -1 , as well as an exceptional capacitance retention of 91.4% after 10,000 cycles. This work affords an effective strategy to yield a promising polyimide derived carbon material for high-performance supercapacitors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A bio-inspired cellulose paper-poly(amidoxime) composite hydrogel is explored via UV-polymerization. This hydrogel has a highly efficient uranium capture capacity of up to 6.21 mg g -1 for W U /W dry gel and 12.9 mg g -1 for W U /W poly(amidoxime) in seawater for 6 weeks, due to its enhanced hydrophilicity, good hydraulic/ionic conductivity and broad-spectrum antibacterial performance.

The titanium carbide nanosheets (MXene) hold great potential for fabricating high‐performance electronics due to their two‐dimensional layered structure, high electrical conductivity, and versatile surface chemistry. However, assembling the small MXene nanosheets into flexible macroscopic films for wearable electronics still remains a challenge. Herein, we report the hierarchical assembling of MXene nanosheets and cellulose nanofibers into high‐performance composite films via an electrostatic self‐assembly strategy induced by polyethyleneimine. Benefited from the nacre‐like microstructure of MXene "bricks" and cellulose nanofibers "mortars" interlocked by polyethyleneimine via hydrogen bonding and electrostatic interaction, composite films possess integrated superior flexibility, high tensile strength, and stable electrical conductivity, which are advantageous for wearable electronic applications. To provide a proof‐of‐concept design, a symmetric quasi‐solid‐state supercapacitor with the as‐prepared composite film as electrode is fabricated, which exhibits a specific capacitance of 93.9 mF cm−2 at a current density of 0.1 mA cm−2 and almost constant capacitive behavior under different bending states. In addition, the composite film possesses capacities of electrothermal conversion and complete degradation in a hydrogen peroxide solution. These results demonstrate that the electrostatically self‐assembled composite films hold great promise in the development of highly flexible, mechanically robust, and environmentally friendly energy storage and conversion devices. [ABSTRACT FROM AUTHOR]

Due to the rapid development of intelligent technology and the pursuit of green environmental protection, responsive materials with single response and actuation can no longer meet the requirements of modern technology for intelligence, diversification, and environmental friendliness. Therefore, intelligent responsive materials have received much attention. In recent years, with the development of new materials and technologies, cellulose materials have become increasingly used as responsive materials due to their advantages of sustainability and renewability. This review summarizes the relevant research on cellulose-based intelligent responsive materials in recent years. According to the stimuli responses, they are divided into temperature-, light-, electrical-, magnetic-, and humidity-responsive types. The response mechanism, application status, and development trend of cellulose-based intelligent responsive materials are summarized. Finally, the future perspectives on the preparation and applications of cellulose-based intelligent responsive materials are presented for future research directions. [ABSTRACT FROM AUTHOR]

The human skin, an important sensory organ, responds sensitively to external stimuli under various harsh conditions. However, the simultaneous achievement of mechanical/thermal sensitivity and extreme environmental tolerance remains an enormous challenge for skin‐like hydrogel‐based sensors. In this study, a novel skin‐inspired hydrogel–elastomer hybrid with a sandwich structure and strong interfacial bonding for mechanical–thermal multimode sensing applications is developed. An inner‐layered ionic hydrogel with a semi‐interpenetrating network is prepared using sodium carboxymethyl cellulose (CMC) as a nanofiller, lithium chloride (LiCl) as an ionic transport conductor, and polyacrylamide (PAM) as a polymer matrix. The outer‐layered polydimethylsiloxane (PDMS) elastomers fully encapsulating the hydrogel endow the hybrids with improved mechanical properties, intrinsic waterproofness, and long‐term water retention (>98%). The silane modification of the hydrogels and elastomers imparts the hybrids with enhanced interfacial bonding strength and integrity. The hybrids exhibit a high transmittance (~91.2%), fatigue resistance, and biocompatibility. The multifunctional sensors assembled from the hybrids realize real‐time temperature (temperature coefficient of resistance, approximately −1.1% °C−1) responsiveness, wide‐range strain sensing capability (gauge factor, ~3.8) over a wide temperature range (from −20°C to 60°C), and underwater information transmission. Notably, the dual‐parameter sensor can recognize the superimposed signals of temperature and strain. The designed prototype sensor arrays can detect the magnitude and spatial distribution of forces and temperatures. The comprehensive performance of the sensor prepared via a facile method is superior to that of most similar sensors previously reported. Finally, this study develops a new material platform for monitoring human health in extreme environments. [ABSTRACT FROM AUTHOR]

Directional freeze-drying is considered to regulate the structure of nanocellulose aerogels with special performances. In this work, TEMPO-oxidized cellulose nanofiber aerogels with high porosity (> 99.5%) and low density (~ 7 mg/cm3) were produced by different freeze-drying methods. The effects of temperature, freezing reagents and freezing methods on the structure and properties of aerogels were investigated. Among them, an anisotropic cellulose aerogel was obtained using a simple and flexible directional freezing in ethanol of − 30 °C by a self-made directional freezer. Our results demonstrated that it could present honeycomb-like pores in the transverse direction and regular directional tunnels in the longitudinal direction, and some attractive features, such as high water adsorption (120 g/g) and stability in water. Compared with other aerogels, this anisotropic structure also provided the aerogel with excellent compressive property (15.2 kPa) and faster liquid transport (4.95 mm/s) in the longitudinal direction than in other directions. The distinctive aerogels based on nanocellulose by directional freeze-drying are also expected to be combined with multifunctional materials to achieve directional applications to meet the requirements of different fields. [ABSTRACT FROM AUTHOR]

Preparing a lightweight yet high-strength bio-based structural material with sustainability and recyclability is highly desirable in advanced applications for architecture, new energy vehicles and spacecraft. In this study, we combined cellulose scaffold and aramid nanofiber (ANF) into a high-performance bulk material. Densification of cellulose microfibers containing ANF and hydrogen bonding between cellulose microfibers and ANF played a crucial role in enhanced physical and mechanical properties of the hybrid material. The prepared material showed excellent tensile strength (341.7 MPa vs. 57.0 MPa for natural wood), toughness (4.4 MJ/m3 vs. 0.4 MJ/m3 for natural wood) and Young's modulus (24.7 GPa vs. 7.2 GPa for natural wood). Furthermore, due to low density, this material exhibited a superior specific strength of 285 MPa·cm3·g−1, which is remarkably higher than some traditional building materials, such as concrete, alloys. In addition, the cellulose scaffold was infiltrated with ANFs, which also improved the thermal stability of the hybrid material. The facile and top-down process is effective and scalable, and also allows one to fully utilize cellulose scaffolds to fabricate all kinds of advanced bio-based materials. [ABSTRACT FROM AUTHOR]

Constructing lightweight and porous adsorbents which can effectively remove dye contaminants is of great significance in the field of the sewage treatment. In this work, anisotropic cellulose nanofibril (CNF) composite sponges assisted by rectorites are fabricated through directional freeze-drying. The resulted composite sponge exhibits the superior saturated adsorption capacity and removal efficiency of 120.0 mg/g and 96.1% for methylene blue (MB), respectively, which is better than the pure CNF sponge and rectorite powders. This is attributed to the strong electrostatic interaction between CNFs and MB, and good cation exchange property of rectorites inside the three-dimensional (3D) highly porous composite sponge. The MB adsorption process of the composite sponge fits to the pseudo-second-order kinetic model and the Langmuir isotherm model well, which is affected by both boundary layer and intraparticle diffusion, resulting in a theoretical maximum adsorption capacity of 214.6 mg/g. Moreover, it also possesses a selective adsorption capacity for anionic and cationic dyes, which is expected to realize the separation treatment of different dyes according to actual application requirements. [Display omitted] • Anisotropic CNF/rectorite composite sponge by directional freeze-drying. • Superior MB adsorption capacity and removal rate of 120.0 mg/g and 96.1%. • Selective adsorption and separation capacity for anionic and cationic dyes. • Detailed evaluation of the adsorption behavior and mechanism. [ABSTRACT FROM AUTHOR]

• PPy-coated P(NIPAM-ABP) electrospun nanofiber can provide high strength. • PPy-coating by in situ polymerization can provide high light-responsive. • The actuator owns ultrafast deformation and rapid recovery. • The actuator can realize various 3D programmable complex deformations. • We have explored new biomimetic devices based on the advantages of the actuator. Intelligent hydrogels are promising for biomimetic actuators, but acquiring actuations with both high speed and powerful force is still extremely difficult. Herein, a new robust polypyrrole (PPy)-coated copoly(isopropylacrylamide-4-benzoylphenyl acrylate) [P(NIPAM-ABP)] electrospun light-responsive hydrogel is explored. The (PPy)-coated P(NIPAM-ABP) hydrogel can be obtained via in-situ polymerization of pyrroles on the nanofiber-oriented electrospun P(NIPAM-ABP) hydrogel. Compared with original P(NIPAM-ABP) hydrogel, this PPy-coated P(NIPAM-ABP) hydrogel can integrate highly-enhanced mechanical strength (from 1.21 to 5.12 MPa of tensile strength) and ultrahigh-efficiency of photothermal conversion together. In addition, the orientation of P(NIPAM-ABP) nanofibers can still maintain well for programmable complex deformations. Consequently, the as-prepared robust bi-hydrogel actuator with ultrafast and complex deformations has been achieved, through bonding the PPy-P(NIPAM-ABP) hydrogel membrane with a polyethylene glycol diacrylate-cellulose nanofiber (PEGDA-CNF) composite hydrogel membrane via interfacial ultraviolet (UV) polymerization of PEGDA monomers. Several light-responsive biomimetic actuating devices have been achieved, which owning powerful force (can grab up 100 times of self-weight), rapid speed (1285.71°/s of folding) or precisely programmable complex deformations. Furthermore, two biomimetic devices with synergistic functions of the three advantages above have been explored, which can mimic the child's sit-up and the starfish's continuous crawling movement respectively. This work provides a robust remotely-controlled light-responsive hydrogel actuator with powerful force, ultrafast speed and programmable complex actuations, which will inspire the design and fabrication of novel soft biomimetic actuating materials and systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyformamide-derived carbon nanowire arrays are in-situ synthesized as N-containing carbon coatings for cellulose-based carbon fibers. • The green H 2 O 2 solution acts as both dopant and activator. • The assembled solid-state symmetric supercapacitor yields encouraging capacitive properties. • This work paves a cost-effective and universal avenue toward structural and compositional engineering of electrodes in energy-related devices. Free-standing porous carbon have risen to prominent electrode materials for high-rate solid-state supercapacitors, yet they are still plagued by uneconomical petrochemical feedstocks, tedious slurry-casting processes, and suboptimal performance. Herein, a dual‐strategy of combining free-standing nitrogen-doped carbon nanowire array coating and pore engineering is designed to boost the performance of cellulose-derived carbon electrodes. Polyformamide-derived carbon nanowire arrays are in-situ synthesized as N-containing carbon coatings for cellulose-based carbon fibers. More intriguingly, H 2 O 2 activation further enhances the hierarchical porous structure. Benefiting from the synergistic effect of free-standing feature, high electrolyte compatibility, interconnected conductive fiber networks, well-developed hierarchical porous structure and stable heteroatom-doped carbon coatings, the designed electrodes possess high accessibility of electrolyte ions and effective ion/electron transport channels. Thus, the specific capacitance reaches 275.6 F g−1 at 0.5 A g−1 for aqueous supercapacitor. The solid-state symmetric supercapacitor demonstrates the specific capacitance of 126.5 F g−1 at 0.5 A g−1 with the capacitance retention of 64.5% even when the current densities increased by 40-folds. Their promising energy density (17.5 Wh kg−1) and power density (12.3 kW kg−1) closing to the state-of-the-art biomass-derived free-standing solid-state symmetric supercapacitors. This breakthrough symbolizes a step forward in the advancement of biomass as high‐performance electrodes for supercapacitors. [ABSTRACT FROM AUTHOR]

Stretchable electroluminescent (EL) devices show great potential for wearable displays. However, the integration of stretchability, flexibility, temperature-tolerance, waterproofness and biocompatibility into a single EL device remains a challenge. Herein, we report a facile full solution-process method for a novel EL device consisting of a dielectric luminescent layer sandwiched between two silver nanowires-cellulose nanocrystals with II crystalline allomorphs/polydopamine-polydimethylsiloxane (CNC II-AgNWs/PDA-PDMS) electrodes. CNC II is used as a green dispersant, film-forming agent and antioxidant to improve the optical, electrical, mechanical and antioxidant properties of the electrodes. The electrodes exhibit a smooth surface, low sheet resistance (~11 Ω sq−1), high transparency (~79.2 %), ideal stretchability (~100 % strain) and excellent inoxidizability. The assembled EL devices with outstanding tensile stability and fatigue resistance demonstrate excellent luminance, flexibility and stretchability underwater and at extreme temperatures, as well as intrinsic biocompatibility. Our multifunctional EL devices with outstanding integrated properties provide new insights for the next-generation flexible electronics. [Display omitted] [ABSTRACT FROM AUTHOR]

Hierarchical porous carbon-based electrodes, benefiting from their facilitated ion diffusion and electron conduction, have demonstrated enormous potential in supercapacitors. The preparation of hierarchical carbons with uniformity and appropriate porosity, however, still remains a grand challenge, which hinders their widespread applications. Herein, a hierarchical porous polyimide-derived carbon electrode (CPC-Fe/Zn) has been fabricated by employing bimetallic salts (Fe/Zn) as precursor and template to activate the cellulose/polyimide (PI) carbon (CPC). Originating from suitable distribution of mesopores and micropores, the obtained CPC-Fe/Zn delivers a high specific capacitance of 420 F/g at a current density of 1 A/g. Moreover, a symmetric supercapacitor device assembled with CPC-Fe/Zn exhibits delivers an energy density of 35.5 Wh/kg at a power density of 800 W/kg. Even at a larger current density of 20 A/g, the specific capacitance retention of such device still remains 92.5 % after 10,000 cycles, showing the rate performance and stability. This work has proposed a bimetallic salts template-assisted strategy to precisely modulate of the pore structure of carbon electrodes, which provides a promising platform to design superior electrodes for various electrochemical systems. [Display omitted] • The hierarchically porous structure of the material can be modulated precisely. • The symmetric supercapacitor exhibited a remarkable energy density of 35.5 Wh/kg @ 1000 W/kg. • The specific capacitance retention of symmetric supercapacitor reached 92.5 % after 10,000 cycles. [ABSTRACT FROM AUTHOR]

Renewable cellulose-based papers are considered as a good resource for energy storage devices owing to their interlaced microfibrillar structure and high electrolyte absorptivity. Herein, an all-cellulose-based solid-state high-rate supercapacitor assembled with cellulose paper-derived self-supporting porous carbon electrodes and filter paper separator is designed. Benefiting from ingenious surface chemistry and pore structure engineering, the electrodes possess interconnected network structure, hierarchical pores, and appropriate N/O doping levels. The electrode demonstrates high specific capacitance (222.2 F g−1 at 0.2 A g−1), prominent rate capability (120.1 F g−1 at 100 A g−1), and outstanding cyclic stability (98.7 % capacitance retention after 20,000 cycles at 80 A g−1), which surpass most of cellulose-based self-supporting carbon electrodes ever reported. By integrating the well-designed electrodes with a piece of filter paper separator, the assembled symmetric solid-state supercapacitor (1.2 V) achieves an encouraging specific capacitance of 115.0 F g−1 along with an impressive energy density of 22.9 Wh kg−1 and a maximum power density of 15.9 kW kg−1. Moreover, the symmetric supercapacitor with 1 M Et 4 NBF 4 organic electrolyte (3 V) delivered a maximum energy density and power density of 62.5 Wh kg−1 and 54.9 kW kg−1, respectively. This study proposes a design concept of all-cellulose-based solid-state supercapacitors, which presents a promising direction toward environmentally friendly and sustainable energy storage technology. [Display omitted] • A facile solvothermal reaction and carbonization/activation route was proposed to tailor pore and surface characteristics. • All-cellulose-based symmetric supercapacitor was designed by integrating N/O-CP-50 electrodes and filter paper separator. • Excellent comprehensive performance was achieved for N/O-CP-50-based symmetric supercapacitor. • The typical all-cellulose-based solid-state devices balance the cost and performance of portable electronic devices. [ABSTRACT FROM AUTHOR]

• CBRSi is designed and synthesized through alkyne insertion, oxidation and esterification reactions. • CBRSi-CP is obtained via coupling and polycondensation reaction. • CBRSi-CP is transparant, flexible , superhydrophobic, and thermally stable. Cellulose Nanopaper is a kind of green material prepared from renewable cellulose nanofibrils. In order to achieve multi-functionization of cellulose nanopaper, thermally stable o-carborane moieties were introduced and grafted on the surface of cellulose nanopaper through silane coupling process. Firstly, o-carboranyl silane was designed and synthesized through alkyne insertion, oxidation and esterification reactions. Then o-carboranyl silane modified cellulose nanopaper was prepared via in-situ coupling and polycondensation reaction between o-carboranyl silane and cellulose nanopaper. The obtained nanopaper shows superhydrophobicity together with good transparency and flexibility. Besides, it exhibits improved dimensional stability and thermal stability owing to the introduction of o-carborane moiety. [ABSTRACT FROM AUTHOR]