Electrospun Core-Shell Nanofibrous Membranes with Nanocellulose-Stabilized Carbon Nanotubes for Use as High-Performance Flexible Supercapacitor Electrodes with Enhanced Water Resistance, Thermal Stability, and Mechanical Toughness

N-DMBI Doping of Carbon Nanotube Yarns for Achieving High n-Type Thermoelectric Power Factor and Figure of Merit

The application of carbon nanotube (CNT) yarns as thermoelectric materials for harvesting energy from low-grade waste heat including that generated by the human body, is attracting considerable attention. However, the lack of efficient n-type CNT yarns hinders their practical implementation in thermoelectric devices. This study reports efficient n-doping of CNT yarns, employing 4-(1, 3-dimethyl-2, 3-dihydro-1H-benzimidazole-2-yl) phenyl) dimethylamine (N-DMBI) in alternative to conventional n-dopants, with o-dichlorobenzene emerging as the optimal solvent. The small molecular size of N-DMBI enables highly efficient doping within a remarkably short duration (10 s) while ensuring prolonged stability in air and at high temperature (150 °C). Furthermore, Joule annealing of the yarns significantly improves the n-doping efficiency. Consequently, thermoelectric power factors (PFs) of 2800, 2390, and 1534 µW m-1  K-2 are achieved at 200, 150, and 30 °C, respectively. The intercalation of N-DMBI molecules significantly suppresses the thermal conductivity, resulting in the high figure of merit (ZT) of 1.69×10-2 at 100 °C. Additionally, a π-type thermoelectric module is successfully demonstrated incorporating both p- and n-doped CNT yarns. This study offers an efficient doping strategy for achieving CNT yarns with high thermoelectric performance, contributing to the realization of lightweight and mechanically flexible CNT-based thermoelectric devices.

Biomedical Approach of Nanotechnology and Biological Risks: A Mini-Review

Nanotechnology has played a prominent role in biomedical engineering, offering innovative approaches to numerous treatments. Notable advances have been observed in the development of medical devices, contributing to the advancement of modern medicine. This article briefly discusses key applications of nanotechnology in tissue engineering, controlled drug release systems, biosensors and monitoring, and imaging and diagnosis. The particular emphasis on this theme will result in a better understanding, selection, and technical approach to nanomaterials for biomedical purposes, including biological risks, security, and biocompatibility criteria.

Robust, self-adhesive and anti-bacterial silk-based LIG electrodes for electrophysiological monitoring

Flexible wearable electrodes have been extensively used for obtaining electrophysiological signals towards smart health monitoring and disease diagnosis. Here, low-cost, and non-conductive silk fabric (SF) have been processed into highly conductive laser induced graphene (LIG) electrodes while maintaining the original structure of SF. A CO2-pulsed laser was utilized to produce LIG-SF with controlled sheet resistance and mechanical properties. Laser processing of SFs under optimized conditions yielded LIG-SF electrodes with a high degree of homogeneity on both, top and bottom layers. Silk fibroin/Ca2+ adhesive layers effectively promoted the adhesive, anti-bacterial properties and provided a conformal contact of LIG-SF electrodes with human skin. Compared with conventional Ag/AgCl electrodes, LIG-SF electrodes possesses a much lower contact impedance in contact with human skin enabling highly stable electrophysiological signals recording. The applicability of adhesive LIG-SF electrodes to acquire electrocardiogram (ECG) signals was investigated. ECG signals recordings of adhesive LIG-SF electrodes showed excellent performance compared to conventional Ag/AgCl electrodes at intense body movements while running at different speeds for up to 9 km over a duration of 24 h. Therefore, our proposed adhesive LIG-SF electrodes can be applied for long-term personalized healthcare monitoring and sports management applications.

Cellulose-Based Conductive Materials for Energy and Sensing Applications

Cellulose-based conductive materials (CCMs) have emerged as a promising class of materials with various applications in energy and sensing. This review provides a comprehensive overview of the synthesis methods and properties of CCMs and their applications in batteries, supercapacitors, chemical sensors, biosensors, and mechanical sensors. Derived from renewable resources, cellulose serves as a scaffold for integrating conductive additives such as carbon nanotubes (CNTs), graphene, metal particles, metal-organic frameworks (MOFs), carbides and nitrides of transition metals (MXene), and conductive polymers. This combination results in materials with excellent electrical conductivity while retaining the eco-friendliness and biocompatibility of cellulose. In the field of energy storage, CCMs show great potential for batteries and supercapacitors due to their high surface area, excellent mechanical strength, tunable chemistry, and high porosity. Their flexibility makes them ideal for wearable and flexible electronics, contributing to advances in portable energy storage and electronic integration into various substrates. In addition, CCMs play a key role in sensing applications. Their biocompatibility allows for the development of implantable biosensors and biodegradable environmental sensors to meet the growing demand for health and environmental monitoring. Looking to the future, this review emphasizes the need for scalable synthetic methods, improved mechanical and thermal properties, and exploration of novel cellulose sources and modifications. Continued innovation in CCMs promises to revolutionize sustainable energy storage and sensing technologies, providing environmentally friendly solutions to pressing global challenges.

Nanocelluloses as sustainable membrane materials for separation and filtration technologies: Principles, opportunities, and challenges

Membrane technology is of great interest in various environmental and industrial applications, where membranes are used to separate different mixtures of gas, solid-gas, liquid-gas, liquid-liquid, or liquid-solid. In this context, nanocellulose (NC) membranes can be produced with predefined properties for specific separation and filtration technologies. This review explains the use of nanocellulose membranes as a direct, effective, and sustainable way to solve environmental and industrial problems. The different types of nanocellulose (i.e., nanoparticles, nanocrystals, nanofibers) and their fabrication methods (i.e., mechanical, physical, chemical, mechanochemical, physicochemical, and biological) are discussed. In particular, the structural properties of nanocellulose membranes (i.e., mechanical strength, interactions with various fluids, biocompatibility, hydrophilicity, and biodegradability) are reviewed in relation to membrane performances. Advanced applications of nanocellulose membranes in reverse osmosis (RO), microfiltration (MF), nanofiltration (NF), and ultrafiltration (UF) are highlighted. The applications of nanocellulose membranes offer significant advantages as a key technology for air purification, gas separation, and water treatment, including suspended or soluble solids removal, desalination, or liquid removal using pervaporation membranes or electrically driven membranes. This review will cover the current state of research, future prospects, and challenges in commercializing nanocellulose membranes with respect to membrane applications.

Recycling of Waste Bamboo Biomass and Papermaking Waste Liquid to Synthesize Sodium Lignosulfonate/Chitosan Glue-Free Biocomposite

The development of the paper industry has led to the discharge of a large amount of papermaking waste liquid containing lignosulfonate. These lignin black liquids cause a lot of pollution in nature, which runs counter to the current environmental protection strategy under the global goal. Through the development and use of lignosulfonate in papermaking waste liquid to increase the utilization of harmful substances in waste liquid, we aim to promote waste liquid treatment and reduce environmental pollution. This paper proposes a new strategy to synthesize novel glue-free biocomposites with high-performance interfacial compatibility from papermaking by-product sodium lignosulfonate/chitosan (L/C) and waste bamboo. This L/C bamboo biocomposite material has good mechanical properties and durability, low formaldehyde emissions, a high recovery rate, meets the requirements of wood-based panels, and reduces environmental pollution. This method is low in cost, has the potential for large-scale production, and can effectively reduce the environmental pollution of the paper industry, promoting the recycling of biomass and helping the future manufacture of glue-free panels, which can be widely used in the preparation of bookcase, furniture, floor and so on.

High mass loading paper-based electrode material with cellulose fibers under coordination of zirconium oxyhydroxide nanoparticles and sulfosalicylic acid

With the rapid expansion of the flexible electronics market, it is critical to develop high-performance flexible energy storage electrode materials. Cellulose fibers, which are sustainable, low cost, and flexible, fully meet the requirements of flexible electrode materials, but they are electrically insulating and cause a decrease in energy density. In this study, high-performance paper-based flexible electrode materials (PANI:SSA/Zr-CFs) were prepared with cellulose fibers and polyaniline. A high mass loading of polyaniline was wrapped on zirconia hydroxide-modified cellulose fibers under metal-organic acid coordination through a facile in situ chemical polymerization process. The increase in mass loading of PANI on cellulose fibers not only improves the electrical conductivity but also enhances the area-specific capacitance of the flexible electrodes. The results of electrochemical tests show that the area specific capacitance of the PANI:SSA/Zr-CFs electrode is 4181 mF/cm² at 1 mA/cm², which is more than two times higher than that of the electrode with PANI on pristine CFs. This work provides a new strategy for the design and manufacture of high-performance flexible electronic electrodes based on cellulose fibers.

Perspectives on the Lindman Hypothesis and Cellulose Interactions

In the history of cellulose chemistry, hydrogen bonding has been the predominant explanation when discussing intermolecular interactions between cellulose polymers. This is the general consensus in scholarly textbooks and in many research articles, and it applies to several other biomacromolecules' interactions as well. This rather unbalanced description of cellulose has likely impacted the development of materials based on the processing of cellulose-for example, via dissolution in various solvent systems and regeneration into solid materials, such as films and fibers, and even traditional wood fiber handling and papermaking. In this review, we take as a starting point the questioning of the general description of the nature of cellulose and cellulose interactions initiated by Professor Björn Lindman, based on generic physicochemical reasoning about surfactants and polymers. This dispute, which became known as "the Lindman hypothesis", highlights the importance of hydrophobic interactions in cellulose systems and that cellulose is an amphiphilic polymer. This paper elaborates on Björn Lindman's contribution to the subject, which has caused the scientific community to revisit cellulose and reconsider certain phenomena from other perspectives.

Molecular Engineering of Hierarchical Conducting Polymer Composites for Highly Stable Supercapacitors

Long cycle life and high energy/power density are imperative to energy storage systems. Polyaniline (PANI) has shown great potential as an electrode material but is limited by poor cycling and rate performance. We present a molecular design approach of binding short-chain aniline trimers (ATs) and carbon nanotubes (CNTs) through the formation of amide covalent linkages enabled by a simple laser scribing technique. The covalently coupled AT/CNT (cc-AT/CNT) composite retains 80% of its original capacitance after 20 000 charge/discharge cycles, which readily outperforms long-chain PANI/CNT composites without covalent connections. The compact AT/CNT heterointerfaces produce fast charge/discharge kinetics and excellent rate capability. The flexible symmetric quasi-solid-state devices can be stably cycled beyond 50 000 cycles, at least 5 times longer than most PANI/CNT-based symmetric supercapacitors reported to date. This molecular design of durable conducting polymer-based electrode materials enabled by laser irradiation presents a feasible approach toward robust advanced energy storage devices.

Facile preparation of nanocellulose/multi-walled carbon nanotube/polyaniline composite aerogel electrodes with high area-specific capacitance for supercapacitors

As a natural biological macromolecule, nanocellulose is a promising substrate for high-performance supercapacitor electrodes. However, it shows that a low area-specific capacitance can limit its use. To strengthen the area-specific capacitance of nanocellulose-based composite aerogel electrodes to obtain high-performance supercapacitors, we combined the addition of conductive materials and physical cross-linking. After physical cross-linking and polyaniline embedding in the original conductive framework, a nanocellulose-based composite aerogel with a conductive network and outstanding electrochemical performance was obtained. The good electrochemical performance of the composite aerogel film electrode can be attributed to the high specific surface area of 46.32 m²·g^-1, mesoporous structure, and uniform growth of polyaniline. The electrode exhibited the highest area-specific capacitance of 2176.3 mF·cm^-2 at a current density of 1 mA·cm^-2. Even at a current density of 10 mA·cm^-2, the capacitance was retained at 1071.67 mF·cm^-2, thereby showing good rate performance. Furthermore, the as-prepared aerogel film electrode exhibited electrochemical stability with a capacitance retention of 64 % at a current density of 10 mA·cm^-2 after 1050 cycles. The as-assembled all-solid-state supercapacitor showed the highest area-specific capacitance of 968.94 mF·cm^-2 at a current density of 0.5 mA·cm^-2 and considerable energy and power density of 86.1 μWh·cm^-2 and 200 μW·cm^-2, respectively. In this study, we demonstrated that the proper construction of conductive networks by conductive polymers could maximize electrochemical performance.

Preparation and Study of Polyvinyl Alcohol Gel Structures with Acrylamide and 2-Acrylamido-2-methyl-1-propanesulfonic Acid for Application in Saline Oil Reservoirs for Profile Modification

Polymer gels can be effectively applied to plug fractured reservoirs and carbonate cave strata. Herein, polyvinyl alcohol (PVA), acrylamide, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) were used as raw materials to prepare interpenetrating three-dimensional network polymer gels using formation saltwater in the Tahe oilfield (Tarim Basin, NW China) as a solvent. The effect of AMPS concentration on the gelation properties of PVA in high-temperature formation saltwater was analyzed. Further, the effect of PVA concentration on the strength and viscoelastic properties of polymer gel was studied. The polymer gel could retain stable continuous entanglement at 130 °C and exhibited satisfactory thermal stability. Continuous step oscillation frequency tests showed that it exhibited an excellent self-healing performance. Scanning electron microscopy images of the simulated core by gel plugging showed that the polymer gel could firmly fill the porous media, indicating that the polymer gel exhibits excellent application prospects in oil and gas reservoirs under high-temperature and high-salinity conditions.

High performance flexible and antibacterial strain sensor based on silver‑carbon nanotubes coated cellulose/polyurethane nanofibrous membrane: Cellulose as reinforcing polymer blend and polydopamine as compatibilizer

In this study, ethyl cellulose was used as the second-phase polymer blended with polyurethane to make nanofibrous membrane as antibacterial strain sensor. The results indicated that ethyl cellulose could regulate the morphology of polyurethane through strong hydrogen bonding, which observably enhanced the nanofiber uniformity of polyurethane. Furthermore, rigid cellulose also remarkably improved the mechanical strength and thermal stability of the nanofibrous membrane. After being coated with silver nanoparticles and carbon nanotubes assisted by polydopamine (PDA), the membrane with outstanding bacteria inhibition performance exhibited outstanding sensitivity toward external mechanical stretching, as well as real-time motion of human body parts. The conductive composite membrane possessed sensitive and regular resistance feedback to 100 cycles of varied human motions. The cellulose in the nanofiber structure ensured the shape recovery and longtime use stability of the membrane. This study proposed a novel thinking for the construction of high performance strain sensor by rational introduction of rigid polysaccharide into the polymer matrix.

Balanced Mechanical and Biotribological Properties of Polymer Composites Reinforced by a 3D Interlocked Si3N4 Nanowire Membrane

Polymer composites have great potential applications in the hip joint replacement, where the combinations of high mechanical strength and excellent biotribological properties are required. In this work, a well-dispersed three-dimensional (3D) silicon nitride nanowire membrane (SNm) designed as a reinforcement and brushite (Bs) served as bioactive filler are constructed into the polymer matrix, forming SNm-reinforced Bs/polymer composites (SNm-Bs/Pm). Especially, SNm could form a 3D interlocked structure, where the ultralong silicon nitride nanowires are entangled with each other. SNm could effectively facilitate the penetration of the polymer matrix and improve the cohesion strength of the polymer, thereby promoting mechanical and biotribological properties for SNm-Bs/Pm. The performances for polymer composites are optimized by increasing the layer number of preform. By comparing SNm-Bs/Pm with one-layer preform, the tensile strength of SNm-Bs/Pm with six-layer preforms reaches 83.3 MPa with an increase of 767.7%. In addition, the friction coefficient and wear rate of SNm-Bs/Pm with six-layer preforms in fetal bovine serum medium achieve 0.06 and 0.21 × 10^-14 m³(N·m)^-1 and decrease by 82.4 and 72.4%, respectively. The present work provides a promising methodology of preparing interlocked SNm-reinforced polymer composites with enhanced mechanical and biotribological properties that are potential for hip joint replacement applications.

A Comprehensive Review of Self-Healing Polymer, Metal, and Ceramic Matrix Composites and Their Modeling Aspects for Aerospace Applications

Composites can be divided into three groups based on their matrix materials, namely polymer, metal and ceramic. Composite materials fail due to micro cracks. Repairing is complex and almost impossible if cracks appear on the surface and interior, which minimizes reliability and material life. In order to save the material from failure and prolong its lifetime without compromising mechanical properties, self-healing is one of the emerging and best techniques. The studies to address the advantages and challenges of self-healing properties of different matrix materials are very limited; however, this review addresses all three different groups of composites. Self-healing composites are fabricated to heal cracks, prevent any obstructed failure, and improve the lifetime of structures. They can self-diagnose their structure after being affected by external forces and repair damages and cracks to a certain degree. This review aims to provide information on the recent developments and prospects of self-healing composites and their applications in various fields such as aerospace, automobiles etc. Fabrication and characterization techniques as well as intrinsic and extrinsic self-healing techniques are discussed based on the latest achievements, including microcapsule embedment, fibers embedment, and vascular networks self-healing.

Water-Soluble Poly(vinyl alcohol)/Biomass Waste Composites: A New Route toward Ecofriendly Materials

With the intention to abate the pollution arising from the improper handling of petroleum-based plastic, green composites consisting of biodegradable plastics and biomass wastes have received widespread attention. However, the balance between mechanical performance and biodegradability still has not been reconciled and evaluated. Herein, a concept for water-soluble poly(vinyl alcohol) (PVA)/biomass waste composite materials is proposed. Instead of degrading to small molecules, the PVA matrix can dissolve in water within the soil. Moreover, after PVA was composited with waste cottonseed shell (CTS) using solid-state shearing milling (S³M) technology, considerable mechanical and thermal performance was achieved, with the maximum tensile strength and degradation temperature of the PVA/CTS composites reaching 10.3 MPa and ∼250 °C, respectively. Moreover, the soil burial test demonstrated that even if PVA cannot degraded in environment within a short term, its water-soluble nature ensures its environmental friendliness, as the PVA matrix can dissolve in soil in 10 days without imposing any adverse effects on either plants (wheat) or animals (earthworm). This work not only describes the preparation a series of ecofriendly PVA/biomass composites but also provides new insight into the environmental friendliness of PVA-based materials.

Assessment of thermally stabilized electrospun poly(vinyl alcohol) materials as cell permeable membranes for a novel blood salvage device

The use of Intraoperative Cell Salvage (ICS) is currently limited in oncological surgeries, due to safety concerns associated with the ability of existing devices to successfully remove circulating tumour cells. In this work, we present the first stages towards the creation of an alternative platform to current cell savers, based on the extremely selective immunoaffinity membrane chromatography principle. Non-woven membranes were produced via electrospinning using poly(vinyl alcohol) (PVA), and further heat treated at 180 °C to prevent their dissolution in aqueous environments and preserve their fibrous morphology. The effects of the PVA degree of hydrolysis (DH) (98 % vs 99 %), method of electrospinning (needleless DC vs AC), and heat treatment duration (1-8 h) were investigated. All heat treated supports maintained their cytocompatibility, whilst tensile tests indicated that the 99 % hydrolysed DC electrospun mats were stronger compared to their 98 % DH counterparts. Although, and at the described conditions, AC electrospinning produced fibres with more than double the diameter compared to those from DC electrospinning, it was not chosen for subsequent experiments because it is still under development. Evidence of unimpeded passage of SY5Y neuroblastoma cells and undiluted defibrinated sheep's blood in flow-through filtration experiments confirmed the successful creation of 3D networks with minimum resistance to mass transfer and lack of non-specific cell binding to the base material, paving the way for the development of novel, highly selective ICS devices for tumour surgeries.

Drug-Loaded and Anisotropic Wood-Derived Hydrogel Periosteum with Super Antibacterial, Anti-Inflammatory, and Osteogenic Activities

Current artificial periostea mainly focus on osteogenic activity but overlook structural and mechanical anisotropy, as well as the importance of antibacterial and anti-inflammatory properties. Here, inspired by the anisotropic structure of wood, the delignified wood (named white wood, WW) with a porous and highly oriented cellulose fiber skeleton was obtained, which was further filled with polyvinyl alcohol (PVA) hydrogel loaded with curcumin (Cur) and phytic acid (PA). The prepared wood-derived hydrogel composite membranes can not only exhibit an obvious anisotropic structure and good mechanical properties but also sustainably release loaded drugs to obtain long-term biological activities. Creatively, PA can effectively improve the bioavailability of Cur; more importantly, Cur and PA play an obvious synergistic effect in antibacterial, anti-inflammatory, and osteogenic activities. Compared with the wood-derived hydrogel composite membranes without drug loading, as well as loaded with Cur or PA only, these loaded with Cur and PA are significantly more conducive to inhibiting the growth of bacteria and inflammatory response and facilitating the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells. This kind of anisotropic wood-derived hydrogel composite membrane with fantastic antibacterial, anti-inflammatory, and osteogenic activities is expected to be ideal artificial periostea.

Sponge-Like Microfiber Electrodes for High-Performance Redox Flow Batteries

Fabricating fiber-based electrodes with a large specific surface area while maintaining high flow permeability is a challenging issue in developing high-performance redox flow batteries. Here, a sponge-like microfiber carbon electrode is reported with a specific surface area of as large as 853.6 m² g^-1 while maintaining a fiber diameter in the range of 5-7 µm and a macropore size of ≈26.8 µm. The electrode is developed by electrospinning cross-linked poly(vinyl alcohol)-lignin-polytetrafluoroethylene precursors, followed by oxidation and pyrolysis. Applying the as-synthesized electrodes to a vanadium redox flow battery enables the battery to achieve an energy efficiency of 79.1% at the current density of 400 mA cm^-2 and a capacity retention rate of 99.94% over 2000 cycles, representing one of the best battery performances in the open literature. The strategy to fabricate sponge-like porous carbon microfibers holds great promise for versatile applications in redox flow batteries and other energy storage systems.

Flexible Hybrid Electronics Nanofiber Electrodes with Excellent Stretchability and Highly Stable Electrical Conductivity for Smart Clothing

In this paper, a side-by-side, dual-nozzle electrospinning process was used to prepare a flexible hybrid electronics (FHE) material with excellent stretchable properties. A highly stable electrical conductivity was also imparted to the resulting membrane electrodes using silver nanoparticles (AgNPs) and carbon-based nanomaterials of different structures. The AgNP/carbon-based nanomaterials were coated onto bicomponent polymer nanofibers (composed of polyurethane (PU) and polyvinylidene difluoride (PVDF)) on the nanofiber membrane. The FHE nanofiber electrodes were finally integrated into clothing designed to accurately measure human body sensing signals (e.g., electrocardiography (ECG) and electromyography (EMG) signals). To effectively increase the high electrical conductivity, a polymer-type dispersant (polyisobutylene-b-poly(oxyethylene)-b-polyisobutylene, a triblock copolymer) was used to effectively and stably disperse AgNPs with different particle sizes and carbon-based nanomaterials with different geometric dimensions (e.g., zero-dimensional carbon black, one-dimensional carbon nanotubes, and two-dimensional graphene) through non-covalent adsorption. Moreover, the bicomponent PVDF-PU nanofibers were immersed in a mixed dispersant of AgNPs and carbon-based nanomaterials at low concentrations, and thermal post-treatment was conducted to improve the electrical conductivity. The AgNP/graphene oxide (GO) nanofiber electrode exhibited a continuous phase with a stable material microstructure after 5000 repetitions of 50% tension-tension fatigue testing. The waveform pattern obtained from the proposed AgNP/GO nanofiber electrode was compared with those of traditional ECG and EMG electrodes. The nanofiber web electrode treated with organic/inorganic mixed dispersants and verified via tests of its electrical and fatigue properties was found to be suitable for long-term ECG and EMG monitoring, and it has excellent potential in wearable smart sensors.

Patternable Nanocellulose/Ti3C2Tx Flexible Films with Tunable Photoresponsive and Electromagnetic Interference Shielding Performances

Nanocellulose-mediated MXene composites have attracted widespread attention in the fields of sustainable energy, wearable sensors, and electromagnetic interference (EMI) shielding. However, the effects of different nanocelluloses on the multifunctional properties of nanocellulose/Ti₃C₂T_x composites still need further exploration. Herein, we use three types of nanocelluloses, including bacterial cellulose (BC), cellulose nanocrystals (CNCs), and 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO)-oxidized cellulose nanofibers (TOCNs), as intercalation to link Ti₃C₂T_x nanosheets via a self-assembly process, improving the dispersibility, film-forming ability, mechanical properties, and multifunctional performances of nanocelluloses/Ti₃C₂T_x hybrids through electrostatic forces and hydrogen bonding. The optimized ultrathin (∼40 μm) TOCN/Ti₃C₂T_x film integrates excellent tensile strength (∼98.89 MPa), long-term stability (during deformation and water erosion), favorable photoelectric response (photosensitivity up to 2620%), and temperature response (reaching 163 °C in only 12 s). Laser-cutting patterned TOCN/Ti₃C₂T_x films are assembled into flexible multifunctional electronics, exhibiting splendid photoresponse performances and tunable electromagnetic energy shielding capability (>96.4%) related to the variation of water content at the film-gel electrolyte interface. Multifunctional patterned devices based on TOCN/Ti₃C₂T_x composite films provide a novel pathway to rationally design wearable EMI devices with photoelectric response and photothermal conversion.

Nitrogen-Doped Porous MXene (Ti3C2) for Flexible Supercapacitors with Enhanced Storage Performance

Flexible supercapacitors (FSCs) are limited in flexible electronics applications due to their low energy density. Therefore, developing electrode materials with high energy density, high electrochemical activity, and remarkable flexibility is challenging. Herein, we designed nitrogen-doped porous MXene (N-MXene), using melamine-formaldehyde (MF) microspheres as a template and nitrogen source. We combined it with an electrospinning process to produce a highly flexible nitrogen-doped porous MXene nanofiber (N-MXene-F) as a self-supporting electrode material and assembled it into a symmetrical supercapacitor (SSC). On the one hand, the interconnected mesh structure allows the electrolyte to penetrate the porous network to fully infiltrate the material surface, shortening the ion transport channels; on the other hand, the uniform nitrogen doping enhances the pseudocapacitive performance. As a result, the as-assembled SSC exhibited excellent electrochemical performance and excellent long-term durability, achieving an energy density of 12.78 Wh kg⁻¹ at a power density of 1080 W kg⁻¹, with long-term cycling stability up to 5000 cycles. This work demonstrates the impact of structural design and atomic doping on the electrochemical performance of MXene and opens up an exciting possibility for the fabrication of highly FSCs.

Biomimetic Microstructured Antifatigue Fracture Hydrogel Sensor for Human Motion Detection with Enhanced Sensing Sensitivity

Antifatigue fracture performance and high sensing sensitivity are key characteristics for hydrogel sensors used in flexible electronic applications. Herein, inspired by human muscle tissues and epidermal skin tissues, an effective and straightforward strategy is proposed to fabricate hydrogel sensors for detecting human motion with antifatigue fracture performance and high sensing sensitivity. The crystalline regions and orientation along the stretching direction of cellulose nanofiber@carbon nanotube nanohybrids in the hydrogels provide antifatigue fracture performance (the crack does not expand after 2000 stretching cycles, and the fatigue threshold was calculated to be 187 J/m2), which protects hydrogels from severe damage during long-term use. In addition, the microstructured surfaces of the hydrogels with a random height distribution increase the contact area and improve the response to weak stimuli, resulting in a sensing sensitivity of 1.11 kPa-1, 18 times higher than that of a flat hydrogel. This sensing sensitivity is higher than those of most of the hydrogel-based pressure sensors that have been reported earlier. By integrating antifatigue fracture performance and enhanced sensing sensitivity, biomimetic microstructured hydrogel sensors show great potential for use in future flexible electronic applications.

Cellulose Nanocrystals (CNC)-Based Functional Materials for Supercapacitor Applications

The growth of industrialization and the population has increased the usage of fossil fuels, resulting in the emission of large amounts of CO_2. This serious environmental issue can be abated by using sustainable and environmentally friendly materials with promising novel and superior performance as an alternative to petroleum-based plastics. Emerging nanomaterials derived from abundant natural resources have received considerable attention as candidates to replace petroleum-based synthetic polymers. As renewable materials from biomass, cellulose nanocrystals (CNCs) nanomaterials exhibit unique physicochemical properties, low cost, biocompatibility and biodegradability. Among a plethora of applications, CNCs have become proven nanomaterials for energy applications encompassing energy storage devices and supercapacitors. This review highlights the recent research contribution on novel CNC-conductive materials and CNCs-based nanocomposites, focusing on their synthesis, surface functionalization and potential applications as supercapacitors (SCs). The synthesis of CNCs encompasses various pretreatment steps including acid hydrolysis, mechanical exfoliation and enzymatic and combination processes from renewable carbon sources. For the widespread applications of CNCs, their derivatives such as carboxylated CNCs, aldehyde-CNCs, hydride-CNCs and sulfonated CNC-based materials are more pertinent. The potential applications of CNCs-conductive hybrid composites as SCs, critical technical issues and the future feasibility of this endeavor are highlighted. Discussion is also extended to the transformation of renewable and low-attractive CNCs to conductive nanocomposites using green approaches. This review also addresses the key scientific achievements and industrial uses of nanoscale materials and composites for energy conversion and storage applications.

Nanocellulose in tissue engineering and bioremediation: mechanism of action

Nanocellulose are nano-sized components which are biodegradable, biocompatible and renewable. It offers mechanical strength and chemical stability in plants and bacteria. The environmental contamination is reduced by employing various bioremediation techniques which usesmicroorganisms like algae, bacteria and fungi as bio-adsorbents. The bio adsorbent property of nanocellulose contribute more for the bioremediation methods and the detailed study of its mechanism and application is essential which is discussed here. The mechanism happening between the contaminant and nanocellulose adsorbent should be explored in detail in order to develop effective new bioremediation strategies. Nanocellulose structural functionalization helps to modify the nanocellulose structure based on which it can be utilized for specific functions. Exploring the mechanisms that contribute to the implementation of nanocellulose in tissue engineering helps for further developments and advancement in the biomedical application of nanocellulose. Not much studies are available that elucidate and study the basic steps involved in the biomedical and environmental usage of nanocellulose. This review has focussed on the basic mechanisms involved in the use of nanocellulose in tissue engineering and bioremediation processes.

Designing a carbon nanofiber-encapsulated iron carbide anode and nickel-cobalt sulfide-decorated carbon nanofiber cathode for high-performance supercapacitors

To meet the crucial demand for high-performance supercapacitors, much effort has been devoted to exploring electrode materials with nanostructures and electroactive chemical compositions. Herein, iron carbide nanoparticles are encapsulated into carbon nanofibers (Fe₃C@CNF-650) through electrospinning and annealing methods. Nickel-cobalt sulfide nanoparticles are hydrothermally grown on electrospun carbon nanofibers (CNF@NiCoS-650). The Faradaic electrochemical reactions of transition metal compounds improve the specific capacitance of the developed electrode. Meanwhile, the electrically conductive framework of carbon nanofibers facilitates Faradic charge transport. In detail, the Fe₃C@CNF-650 anode and CNF@NiCoS-650 cathode achieve specific capacitances of 1551 and 205 F g^-1, respectively, at a current density of 1 A g^-1. A hybrid supercapacitor that is fabricated from the Fe₃C@CNF-650 anode and CNF@NiCoS-650 cathode delivers an energy density of 43.2 Wh kg^-1 at a power density of 800 W kg^-1. The designed nanostructures are promising for practical supercapacitor applications.

Date-Leaf Carbon Particles for Green Enhanced Oil Recovery

Green enhanced oil recovery (GEOR) is an environmentally friendly enhanced oil recovery (EOR) process involving the injection of green fluids to improve macroscopic and microscopic sweep efficiencies while boosting tertiary oil production. Carbon nanomaterials such as graphene, carbon nanotube (CNT), and carbon dots have gained interest for their superior ability to increase oil recovery. These particles have been successfully tested in EOR, although they are expensive and do not extend to GEOR. In addition, the application of carbon particles in the GEOR method is not well understood yet, requiring thorough documentation. The goals of this work are to develop carbon nanoparticles from biomass and explore their role in GEOR. The carbon nanoparticles were prepared from date leaves, which are inexpensive biomass, through pyrolysis and ball-milling methods. The synthesized carbon nanomaterials were characterized using the standard process. Three formulations of functionalized and non-functionalized date-leaf carbon nanoparticle (DLCNP) solutions were chosen for core floods based on phase behavior and interfacial tension (IFT) properties to examine their potential for smart water and green chemical flooding. The carboxylated DLCNP was mixed with distilled water in the first formulation to be tested for smart water flood in the sandstone core. After water flooding, this formulation recovered 9% incremental oil of the oil initially in place. In contrast, non-functionalized DLCNP formulated with (the biodegradable) surfactant alkyl polyglycoside and NaCl produced 18% more tertiary oil than the CNT. This work thus provides new green chemical agents and formulations for EOR applications so that oil can be produced more economically and sustainably.

Electrostatic interaction-controlled dispersion of carbon nanotubes in a ternary composite for high-performance supercapacitors

Effective dispersion of carbon nanotubes (CNTs) is of great importance to achieve their intrinsic performance. Normally, it is believed that CNT dispersion is decided by interactions between CNTs and their dispersants, while other interactions are often neglected. Herein, three ionic surfactants, sodium dodecyl sulfate (SDS), dodecyl dimethyl betaine (BS-12) and cetyltrimethylammonium bromide (CTAB), are used to disperse CNTs in a ternary composite, i.e., poly(p-phenylenediamine)-phosphomolybdic acid@reduced graphene oxide (DMoG), respectively, leading to three different DMoGC composites. It has been found that the CNT dispersion in DMoGC was mainly controlled by electrostatic interactions between the surfactants and DMoG, which further exerted vital influences on the constitution, content, morphology, porous structure and supercapacitive performance of the DMoGC composites. Among the three surfactants, cationic CTAB showed the best CNT dispersion, while amphoteric BS-12 could hardly disperse CNTs in DMoGC, leading to DMoGC-CTAB with a 2 times larger specific surface area (152.3 m² g^-1) and 1.5 times higher specific capacitance (422 F g^-1) than those of DMoGC-(BS-12). Our study can provide valuable guidelines for selecting/designing effective dispersants to prepare multi-component composites containing uniformly dispersed CNTs.

Recent Development and Environmental Applications of Nanocellulose-Based Membranes

Extensive research and development in the production of nanocellulose production, a green, bio-based, and renewable biomaterial has paved the way for the development of advanced functional materials for a multitude of applications. From a membrane technology perspective, the exceptional mechanical strength, high crystallinity, tunable surface chemistry, and anti-fouling behavior of nanocellulose, manifested from its structural and nanodimensional properties are particularly attractive. Thus, an opportunity has emerged to exploit these features to develop nanocellulose-based membranes for environmental applications. This review provides insights into the prospect of nanocellulose as a matrix or as an additive to enhance membrane performance in water filtration, environmental remediation, and the development of pollutant sensors and energy devices, focusing on the most recent progress from 2017 to 2022. A brief overview of the strategies to tailor the nanocellulose surface chemistry for the effective removal of specific pollutants and nanocellulose-based membrane fabrication approaches are also presented. The major challenges and future directions associated with the environmental applications of nanocellulose-based membranes are put into perspective, with primary emphasis on advanced multifunctional membranes.

Simultaneous adsorption for cationic and anionic dyes using chitosan/electrospun sodium alginate nanofiber composite sponges

The coexistence of anionic and cationic dyes in dye wastewater has highlighted a great necessity to develop amphoteric adsorbents for their simultaneous removal. Herein, an amphoteric composite sponge was successfully fabricated by combining chitosan with electrospun sodium alginate nanofiber using lyophilization in acetic acid/water/dioxane mixed solvents, which owned the abundant functional groups and superior microstructure of interconnected pores and nanoscale fibers, beneficial for the adsorption capacity improvement. The optimum adsorption capacities for Acid Blue-113 and Rhodamine B were 926.2 ± 25.7 mg/g and 695.4 ± 17.0 mg/g, respectively, much higher than that of the controlled sample prepared with chitosan and non-spinning sodium alginate in traditional acetic acid/water solvents. Meanwhile, the sponge provided with the superior adsorption performance under various pH environment and cyclic adsorption. Importantly, it had considerable simultaneous adsorption capacity for binary system containing anionic and cationic dyes. Overall, the chitosan/electrospun sodium alginate nanofiber composite sponge shows potential for complex wastewater treatment.

Polyphenol-Metal Ion Redox-Induced Gelation System for Constructing Plant Protein Adhesives with Excellent Fluidity and Cold-Pressing Adhesion

Soy protein (SP) adhesives can resolve several problems with aldehyde-based adhesives, including formaldehyde release and excessive dependence on petroleum-based materials. Nevertheless, their development is hindered by the lack of balance between fluidity and high cold-pressing adhesive strength. A dynamically cross-linked SP adhesive with excellent fluidity and cold-pressing adhesion was developed in this study based on the polyphenol-metal ion redox-induced gelation system. SP was blended with acrylamide (AM), ammonium persulfate (APS), and the tannic acid (TA)-Fe³⁺ complex to prepare an adhesive gel precursor with good fluidity. In situ gelation of SP adhesive was then achieved via AM polymerization, as initiated by redox between TA and Fe³⁺. As expected, the prepared adhesive gel exhibited outstanding cold-pressing bonding strength (650 kPa) to the veneers compared to the neat SP adhesive, which has almost no cold-pressing bonding strength to the veneers. The TA-Fe³⁺ complex induced an in situ gelation system, which endowed the SP adhesive with strong cohesion; the topological entanglement of the adhesive gel in the veneers contributed to tight interfacial combinations. The TA-Fe³⁺ complex served not only as an accelerator of SP adhesive gelation but also as a "cross-linking core" for the cross-link SP adhesive system. The prepared SP-based adhesive also exhibited outstanding hot-pressing bonding strength and mildew resistance. The proposed polyphenol-metal ion-induced in situ gelation strategy may provide a new approach for developing advanced vegetable protein adhesives to replace aldehyde adhesives.

Inherently Conductive Poly(dimethylsiloxane) Elastomers Synergistically Mediated by Nanocellulose/Carbon Nanotube Nanohybrids toward Highly Sensitive, Stretchable, and Durable Strain Sensors

With the rapid development of soft electronics, flexible and stretchable strain sensors are highly desirable. However, coupling of high sensitivity and stretchability in a single strain sensor remains a challenge. Herein, a kind of conductive elastomer is constructed with poly(dimethylsiloxane) (PDMS) and silylated cellulose nanocrystal (SCNC)/carbon nanotube (CNT) nanohybrids through a facile one-pot solution-casting method. The hydrophobic SCNCs can effectively facilitate the dispersion of CNTs in PDMS and synergistically improve the interfacial compatibility between CNTs and the PDMS matrix, resulting in favorable stress and electron transfer in the polymer network. Due to the outstanding electrical conductivity of CNTs and the excellent dispersity and high mechanical performance of SCNCs, combined with the good compatibility between SCNC-mediated carbon nanotubes (SCNC-CNTs) and PDMS, the resulting composite elastomer (SCNC-CNT/PDMS) shows high electrical conductivity (∼2.77 S m^-1), tensile strength (∼5.72 MPa), and fatigue resistance properties. The strain sensor assembled by SCNC-CNT/PDMS demonstrates a high strain range above 100%, appealing strain sensitivity with a gauge factor of 37.11 at 50-100% strain, and long-term stability and durability, which is capable of monitoring both real-time human motions and acoustic vibrations. This work paves a new way for the design and controllable preparation of flexible and stretchable conductive elastomers, demonstrating promising applications in wearable devices and intelligent electronics.

Fiber Surface/Interfacial Engineering on Wearable Electronics

Surface/interfacial engineering is an essential technique to explore the fiber materials properties and fulfil new functionalities. An extensive scope of current physical and chemical treating methods is reviewed here together with a variety of real-world applications. Moreover, a new surface/interface engineering approach is also introduced: self-assembly via π-π stacking, which has great potential for the surface modification of fiber materials due to its nondestructive working principle. A new fiber family member, metal-oxide framework (MOF) fiber shows promising candidacy for fiber based wearable electronics. The understanding of surface/interfacial engineering techniques on fiber materials is advanced here and it is expected to guide the rational design of future fiber based wearable electronics.

Advanced Nanocellulose-Based Composites for Flexible Functional Energy Storage Devices

With the increasing demand for wearable electronics (such as smartwatch equipment, wearable health monitoring systems, and human-robot interface units), flexible energy storage systems with eco-friendly, low-cost, multifunctional characteristics, and high electrochemical performances are imperative to be constructed. Nanocellulose with sustainable natural abundance, superb properties, and unique structures has emerged as a promising nanomaterial, which shows significant potential for fabricating functional energy storage systems. This review is intended to provide novel perspectives on the combination of nanocellulose with other electrochemical materials to design and fabricate nanocellulose-based flexible composites for advanced energy storage devices. First, the unique structural characteristics and properties of nanocellulose are briefly introduced. Second, the structure-property-application relationships of these composites are addressed to optimize their performances from the perspective of processing technologies and micro/nano-interface structure. Next, the recent specific applications of nanocellulose-based composites, ranging from flexible lithium-ion batteries and electrochemical supercapacitors to emerging electrochemical energy storage devices, such as lithium-sulfur batteries, sodium-ion batteries, and zinc-ion batteries, are comprehensively discussed. Finally, the current challenges and future developments in nanocellulose-based composites for the next generation of flexible energy storage systems are proposed.

Nanocellulose-mediated transparent high strength conductive hydrogel based on in-situ formed polypyrrole nanofibrils as a multimodal sensor

A simple method was provided to prepare a transparent, highly conductive, mechanically reinforced, stretchable, and compressible hydrogel. In this system, pyrrole (Py) monomers were gently polymerized and uniformly deposited on the surface of cellulose nanofiber (CNF) via the improved in-situ polymerization. In the opaque PPy@CNF suspension, acrylamide monomers (AM) were dissolved and radical-polymerized to construct the PPy@CNF-PAM hydrogel with the in-situ formation of PPy nanofibrils in the presence of excess ammonium persulfate (APS). The in-situ formed PPy nanofibrils were well intertwined with the CNF and PAM chains, and a highly conductive path was established and permitted visible light to pass through. The amphipathic CNF took along and dispersed PPy aggregates well, and reinforced the hydrogel after formation of PPy nanofibrils. In view of the improved mechanical compressive, stretchable properties and excellent electrical conductivity (4.5 S/m), the resulting hydrogels could serve as a potential electrical device in a range of applications.

3D Hollow Xerogels with Ordered Cellulose Nanocrystals for Tailored Mechanical Properties

Advanced materials with aligned cellulose nanocrystals (CNCs) have attracted much attention due to their remarkable mechanical and optical properties, but most of them still focus on 1D or 2D architectures. Herein, complex 3D architectures as pseudo catenoid hollow xerogels with aligned CNCs are prepared from dynamic hydrogels by mechanical stretching and air-drying process. Aligned CNCs endow the pseudo catenoids with distinct birefringence in addition to reinforcement. The mechanical properties of pseudo catenoid architecture are revealed for the first time to be controlled at two stages on diverse length scales. Both the aligned CNCs on the nanoscale and the geometry of the xerogels affect the mechanical properties. The inwardly curved surface of the pseudo catenoid xerogel makes the structure conducive to energy dissipation. These both stages of controls on the mechanical properties can be adjusted by changing the morphology of the initial hydrogels and the mechanical stretching ratios. These results will provide a new perspective for the design and manufacture advanced materials with tailored mechanical properties and functions.

Cellulose-Based Nanofibril Composite Materials as a New Approach to Fight Bacterial Infections

Antibiotic resistant microorganisms have become an enormous global challenge, and are predicted to cause hundreds of millions of deaths. Therefore, the search for novel/alternative antimicrobial agents is a grand global challenge. Cellulose is an abundant biopolymer with the advantages of low cost, biodegradability, and biocompatibility. With the recent growth of nanotechnology and nanomedicine, numerous researchers have investigated nanofibril cellulose to try to develop an anti-bacterial biomaterial. However, nanofibril cellulose has no inherent antibacterial activity, and therefore cannot be used on its own. To empower cellulose with anti-bacterial properties, new efficient nanomaterials have been designed based on cellulose-based nanofibrils as potential wound dressings, food packaging, and for other antibacterial applications. In this review we summarize reports concerning the therapeutic potential of cellulose-based nanofibrils against various bacterial infections.

Self-Recovery, Fatigue-Resistant, and Multifunctional Sensor Assembled by a Nanocellulose/Carbon Nanotube Nanocomplex-Mediated Hydrogel

Flexible sensors have attracted great research interest due to their applications in artificial intelligence, wearable electronics, and personal health management. However, due to the inherent brittleness of common hydrogels, preparing a hydrogel-based sensor integrated with excellent flexibility, self-recovery, and antifatigue properties still remains a challenge to date. In this study, a type of physically and chemically dual-cross-linked conductive hydrogels based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofiber (TOCN)-carrying carbon nanotubes (CNTs) and polyacrylamide (PAAM) matrix via a facial one-pot free-radical polymerization is developed for multifunctional wearable sensing application. Inside the hierarchical gel network, TOCNs not only serve as the nanoreinforcement with a toughening effect but also efficiently assist the homogeneous distribution of CNTs in the hydrogel matrix. The optimized TOCN-CNT/PAAM hydrogel integrates high compressive (∼2.55 MPa at 60% strain) and tensile (∼0.15 MPa) strength, excellent intrinsic self-recovery property (recovery efficiency >92%), and antifatigue capacity under both cyclic stretching and pressing. The multifunctional sensors assembled by the hydrogel exhibit both high strain sensitivity (gauge factor ≈11.8 at 100-200% strain) and good pressure sensing ability over a large pressure range (0-140 kPa), which can effectively detect the subtle and large-scale human motions through repeatable and stable electrical signals even after 100 loading-unloading cycles. The comprehensive performance of the TOCN-CNT/PAAM hydrogel-based sensor is superior to those of most gel-based sensors previously reported, indicating its potential applications in multifunctional sensing devices for healthcare systems and human motion monitoring.

CNT-rGO Hydrogel-Integrated Fabric Composite Synthesized via an Interfacial Gelation Process for Wearable Supercapacitor Electrodes

We demonstrate a flexible and stretchable supercapacitor assembled via straightforward interfacial gelation of reduced graphene oxide (rGO) with carbon nanotube (CNT) on a stretchable fabric surface. The difference between the redox potential of aqueous graphene oxide (GO) dispersion, prepared using a modified Hummers' method, and of a solid Zn plate, which was used as an external stimulus, induces a spontaneous reduction of GO flakes forming porous CNT-rGO hydrogel at the liquid-solid interface. With the aid of Zn, a macroporous and flexible CNT-rGO hydrogel was fabricated on a stretchable fabric platform using a facile fabrication method, and the CNT-rGO fabric composite was assembled into a supercapacitor to demonstrate its feasibility as a wearable electrode. The porous structure of the as-formed CNT-rGO fabric composite allows excellent electrolyte accessibility and ion transport that result in a fast charge/discharge rate up to 100 mV/s and a large areal capacity of 10.13 mF/cm² at a discharge rate of 0.5 mA (0.1 mA/cm²). The inclusion of one-dimensional CNT as conductive bridges allows an excellent capacity retention of 95.2% after complete folding of the electrode and a capacity retention of 93.3% after 1000 bending cycles. Additional stretching test displayed a high capacity retention of 90.0% even at an applied strain as high as 50%, overcoming previous limitations of brittle graphene-based electrodes. This low-cost, lightweight, easy to synthesize, stretchable supercapacitor holds promise for next-generation wearable electronics and energy storage applications.

Simultaneous trace-level monitoring of seven opioid analgesic drugs in biological samples by pipette-tip micro solid phase extraction based on PVA-PAA/CNT-CNC composite nanofibers followed by HPLC-UV analysis

Electrospun poly(vinyl alcohol)-(PVA)-poly(acrylic acid) (PAA)/carbon nanotubes(CNTs)-cellulose nanocrystal (CNC) (PVA-PAA/CNT-CNC) composite nanofibers were prepared and characterized using Fourier transform-infrared spectroscopy and field emission scanning electron microscopy. The resultant composite was used as an effective and novel sorbent for pipette-tip micro-solid phase extraction (PT-μSPE) of seven opioid analgesics (OAs) in biological samples followed by HPLC-UV analysis. Addition of CNT-CNC with the high specific surface area and plenty of OH-functional groups endows the nanofibers with considerable extraction efficiency. Under the optimum conditions, the linearity was obtained in the range 1.5 to 700.0 ng mL^-1 for morphine, codeine, oxycodone, and tramadol, and 0.5 to 1000.0 ng mL^-1 for nalbuphine, thebaine, and noscapine with coefficient of determination (r²) ≥ 0.9990. Detection limits (LODs) based on S/N = 3 were in the range of 0.15-0.50 ng mL^-1. The relative standard deviations (RSDs) of 4.1-5.4% (intra-day, n = 5) and 5.2-6.4% (inter-day, n = 3) for three consecutive days were achieved. Finally, the efficiency of the PT-μSPE-HPLC-UV method was evaluated for the determination of OAs in human plasma and urine samples with good recoveries (87.3 to 97.8%). A: Schematic illustration for the preparation of PVA-PAA/CNT-CNC composite nanofibers. B: Schematic presentation of applying PVA-PAA/CNT-CNC composite nanofibers as the sorbent in pipette-tip micro solid-phase extraction (PT-μSPE) for the preconcentration of seven opioid analgesic drugs in biological samples before HPLC-UV analysis.

Functional Materials from Nanocellulose: Utilizing Structure-Property Relationships in Bottom-Up Fabrication

It is inherently challenging to recapitulate the precise hierarchical architectures found throughout nature (such as in wood, antler, bone, and silk) using synthetic bottom-up fabrication strategies. However, as a renewable and naturally sourced nanoscale building block, nanocellulose-both cellulose nanocrystals and cellulose nanofibrils-has gained significant research interest within this area. Altogether, the intrinsic shape anisotropy, surface charge/chemistry, and mechanical/rheological properties are some of the critical material properties leading to advanced structure-based functionality within nanocellulose-based bottom-up fabricated materials. Herein, the organization of nanocellulose into biomimetic-aligned, porous, and fibrous materials through a variety of fabrication techniques is presented. Moreover, sophisticated material structuring arising from both the alignment of nanocellulose and via specific process-induced methods is covered. In particular, design rules based on the underlying fundamental properties of nanocellulose are established and discussed as related to their influence on material assembly and resulting structure/function. Finally, key advancements and critical challenges within the field are highlighted, paving the way for the fabrication of truly advanced materials from nanocellulose.

Surface and Interface Engineering for Nanocellulosic Advanced Materials

How do trees support their upright massive bodies? The support comes from the incredibly strong and stiff, and highly crystalline nanoscale fibrils of extended cellulose chains, called cellulose nanofibers. Cellulose nanofibers and their crystalline parts-cellulose nanocrystals, collectively nanocelluloses, are therefore the recent hot materials to incorporate in man-made sustainable, environmentally sound, and mechanically strong materials. Nanocelluloses are generally obtained through a top-down process, during or after which the original surface chemistry and interface interactions can be dramatically changed. Therefore, surface and interface engineering are extremely important when nanocellulosic materials with a bottom-up process are fabricated. Herein, the main focus is on promising chemical modification and nonmodification approaches, aiming to prospect this hot topic from novel aspects, including nanocellulose-, chemistry-, and process-oriented surface and interface engineering for advanced nanocellulosic materials. The reinforcement of nanocelluloses in some functional materials, such as structural materials, films, filaments, aerogels, and foams, is discussed, relating to tailored surface and/or interface engineering. Although some of the nanocellulosic products have already reached the industrial arena, it is hoped that more and more nanocellulose-based products will become available in everyday life in the next few years.