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The development of modern electronics has raised great demand for multifunctional materials to protect electronic instruments against electromagnetic interference (EMI) radiation and ice accretion in cold weather. However, it is still a great challenge to prepare high-performance multifunctional films with excellent flexibilty, mechanical strength, and durability. Here, we propose a layer-by-layer assembly of cellulose nanofiber (CNF)/Ti3C2Tx nanocomposites (TM) on a bacterial cellulose (BC) substrate via repeated spray coating. CNFs are hybridized with Ti3C2Tx nanoflakes to improve the mechanical properties of the functional coating layer and its adhesion with the BC substrate. The densely packed hierarchical structure and strong interfacial interactions endows the TM/BC films with good flexibility, ultrahigh mechanical strength (>250 MPa), and desirable toughness (>20 MJ cm-3). Furthermore, benefiting from the densely packed hierarchical structure, the resultant TM/BC films present outstanding EMI shielding effictiveness of 60 dB and efficient electro-/photothermal heating performance. Silicone encapsulation further imparts high hydrophobicity and exceptional durability against solutions and deformations to the multifunctional films. Impressively, the silicone-coated TM/BC film (Si-TM/BC) exhibits desirable low voltage-driven Joule heating and excellent photoresponsive heating performance, which demonstrates great feasibility for efficient thermal deicing under actual conditions. Therefore, we believe that the Si-TM/BC film with excellent mechanical properties and durability holds great promise for the practical applications of EMI shielding and ice accretion elimination.

Delicately aligned structures of two-dimensional (2D) MXene nanosheets have demonstrated positive effects on applications, especially in electromagnetic interference (EMI) shielding and infrared (IR) stealth. However, precise regulation of structural assembly by theory-guided solution processing is still a great challenge. Herein, one-dimensional (1D) cellulose nanofibers (CNFs) with a high aspect ratio are applied as a reinforcing agent and a rheological modifier for MXene/CNF colloids to fabricate aligned MXene-based materials for EMI shielding and IR stealth. Notably, a systematical rheological study of the MXene/CNF colloids is proposed to determine the optimal solution-processing conditions for finely oriented component arrangement requirements and provides in-depth information on the interactions between the components. The delicately regulated orientation structure assembled by shear inducement is convincingly demonstrated through micro-CT and wide-angle X-ray diffraction/small-angle X-ray scattering (WAXD/SAXS), which endows the MXene/CNF film with a significantly enhanced electrical conductivity of 46 685 S m

Antibacterial hydrogels have been intensively studied due to their wide practical potential in wound healing. However, developing an antibacterial hydrogel that is able to integrate with exceptional mechanical properties, cell affinity, and adhesiveness will remain a major challenge. Herein, a novel hydrogel with antibacterial and superior biocompatibility properties was developed using aluminum ions (Al³⁺) and alginate–dopamine (Alg-DA) chains to cross-link with the copolymer chains of acrylamide and acrylic acid (PAM) via triple dynamic noncovalent interactions, including coordination, electrostatic interaction, and hydrogen bonding. The cationized nanofibrillated cellulose (CATNFC), which was synthesized by the grafting of long-chain quaternary ammonium salts onto nanofibrillated cellulose (NFC), was utilized innovatively in the preparation of antibacterial hydrogels. Meanwhile, alginate-modified dopamine (Alg-DA) was prepared from dopamine (DA) and alginate. Within the hydrogel, the catechol groups of Alg-DA provided a decent fibroblast cell adhesion to the hydrogel. Additionally, the multitype cross-linking structure within the hydrogel rendered the outstanding mechanical properties, self-healing ability, and recycling in pollution-free ways. The antibacterial test in vitro, cell affinity, and wound healing proved that the as-prepared hydrogel was a potential material with all-around performances in both preventing bacterial infection and promoting tissue regeneration during wound healing processes.

Electromagnetic interference (EMI) and radiation of electronic devices are ubiquitous, which are potentially hazardous to the normal operation of electronic equipment and human health. MXenes are extremely attractive in the preparation of EMI shielding materials due to their excellent metallic conductivity and tunable surface chemistry. Herein, by virtue of the designed nanostructure and regulation of interface interactions, we fabricated flexible Fe3O4@Ti3C2Tx MXene/3,4-dihydroxyphenylacetic acid (DOPAC)-epoxidized natural rubber (ENR) elastomers (FMDE) with 3D segregated interconnected structures. The elaborately designed metal-ligand coordination crosslinking between Fe3O4 nanoparticles and DOPAC ligand molecules provides strong interfacial interactions, resulting in significantly reinforced mechanical properties. Compared with Ti3C2Tx/ENR elastomers, the maximum tensile strength and toughness of FMDE are elevadted by ~306% and 475%, respectively. Moreover, the 3D segregated conductive network constructed by Fe3O4@Ti3C2Tx nanoflakes resulted from volume exclusion effect of ENR latex and the introduction of magnetic Fe3O4 nanoparticles with enhanced electromagnetic wave absorption greatly improved the EMI shielding performance of FMDE, exhibiting an excellent EMI shielding effectiveness of up to 58 dB in the X band (8.2–12.4 GHz) and stable EMI shielding capability during repeated deformations. This work provides a promising strategy for the design and manufacture of novel flexible EMI shielding materials.

Three-dimensional (3D) printing technology with satisfactory speed and accuracy has been a powerful force in biomaterial processing. Early studies on 3D printing of biomaterials mainly focused on their biocompatibility and cellular viability while rarely attempted to produce robust specimens. Nonetheless, the biomedical applications of polymers can be severely limited by their inherently weak mechanical properties particularly in bone tissue engineering. In this study, continuous liquid interface production (CLIP) is applied to construct 3D objects of nano-hydroxyapatite (n-HA) filled polymeric biomaterials with complex architectures. Notably, the bioactive and osteoconductive n-HA endows the 3D prints of poly(ethyleneglycol)diacrylate (PEGDA) composites with a high compression strength of 6.5 ± 1.4 MPa, about 342% improvement over neat PEGDA. This work demonstrates the first successful attempt on CLIP 3D printing of n-HA nanocomposites, providing a feasible, cost-effective and patient-specific solution to various fields in the biomedical industry.

A lightweight, flexible, and highly efficient energy management strategy is a requisite for future flexible electronics. Herein, hollow polypyrrole/cellulose hybrid hydrogels featured with biphase porous structures, are firstly designed by in-situ implanting a hollow and continuous polypyrrole conducting network into porous cellulose hydrogels. Such hollow hybrid hydrogels show good mechanical strength and flexibility, enabling its ability to bear severe mechanical deformation without structural damage. Within the hybrid hydrogel, cellulose hydrogel acts as an interior electrolyte reservoir to host movable ions, biphase porous structure offers path for electrolyte ions transportation, and hollow polypyrrole network is responsible for the electrochemical contribution. As a result, a symmetrical supercapacitor assembled with the hollow hybrid hydrogels delivers optimized capacitive properties with a high specific capacitance, a good rate capability, and an enhanced cycling stability. Moreover, no evident loss in capacitance of the device is observed even bended at 180°. This work provides a design of flexible, low-cost, environmental-friendly and high-performance electrode materials for energy conversion and storage systems.

Soft actuation materials are highly desirable in flexible electronics, soft robotics, etc. However, traditional bilayered actuators usually suffer from poor mechanical properties as well as deterio...

Progress toward the integration of electronic sensors with a signal processing system is important for artificial intelligent and smart robotics. It demands mechanically robust, highly sensitive, and self-healable sensing materials which could generate discernible electric variations responding to external stimuli. Here, inspired by the supramolecular interactions of amino acid residues in proteins, we report a self-healable nanostructured Ti3C2MXenes/rubber-based supramolecular elastomer (NMSE) for intelligent sensing. MXene nanoflakes modified with serine through an esterification reaction assemble with an elastomer matrix, constructing delicate dynamic supramolecular hydrogen bonding interfaces. NMSE features desirable recovered toughness (12.34 MJ/m3) and excellent self-healing performance (∼100%) at room temperature. The NMSE-based sensor with high gauge factor (107.43), low strain detection limit (0.1%), and fast responding time (50 ms) can precisely detect subtle human motions (including speech, facial expression, pulse, and heartbeat) and moisture variations even after cut/healing processes. Moreover, NMSE-based sensors integrated with a complete signal process system show great feasibility for speech-controlled motions, which demonstrates promising potential in future wearable electronics and soft intelligent robotics.

In recent years, the huge consumption of energy and the increasing environmental awareness have triggered the need for new types of devices for the collection and storage of green and renewable energy. Owing to the natural abundance, low cost and renewability, biomass-waste-derived energy storage materials offer a great opportunity to address both energy and environmental issues. Herein, we demonstrate for the first time an effective approach to fabricate a high-performance rechargeable Zn–MnO2 battery directly from biomass garbage (reed straw) floating on the ocean. The obtained three-dimensional (3D) electrodes exhibit a honeycomb-like cellular structure with multi-level open channels. This unique architecture not only enables a high mass loading of MnO2 (51.0 mg cm−3), but also provides low-resistance pathways favorable for electrolyte diffusion and ion transport. The resulting battery achieves a remarkable capacity (369.73 mA h g−1 at a low MnO2 loading of 4.9 mg cm−3 and 306.7 mA h g−1 at a MnO2 loading of 51.0 mg cm−3), good rate capability and outstanding cycling stability (retention of 95.2% of the initial capacity after 3000 cycles), which are superior to those of most batteries of this type. When using a gel as the electrolyte, the as-fabricated quasi-solid-state battery possesses an admirable energy density of 20.5 mW h cm−3 (420.1 W h kg−1, based on the mass of MnO2, or 131.5 W h kg−1 based on the total mass of the battery). Impressively, the battery can be safely used in a wide temperature range (−20 to 100 °C) and under a variety of extreme conditions, such as puncturing, bending, hammering, cutting and cropping. This battery is further integrated with a flexible solar cell for a self-sustaining power bar, which is capable of harvesting green and sustainable energy from the surrounding environment and successfully powers wearable electronics. Unlike most of the previous reports on zinc ion batteries, which attempted to improve the electrochemical properties by using more effective active materials, the present study achieves outstanding performance mainly due to the unique structures of the electrodes derived from the biomass waste. Obviously, this method appears to be much simpler and lower in cost, thus having high potential for scale-up manufacturing.

Despite of the fact that polymers have brought tremendous convenience to human life, they have also inevitably caused considerable environmental pollution after their service life. Therefore, a feasible strategy that can effectively recycle waste polymers and endow them with high added value is much desired. Superwetting materials have shown great promise in oily wastewater treatment because of their high oil/water separation efficiency. However, most of these materials present some limitations, such as complex preparation procedures and poor salt tolerance, which hamper their practical applications. In this study, an iron hydroxide@polydopamine@waste polyurethane foam (Fe(OH)

The development of modern electronics has raised great demand for multifunctional materials to protect electronic instruments against electromagnetic interference (EMI) radiation and ice accretion in cold weather. However, it is still a great challenge to prepare high-performance multifunctional films with excellent flexibilty, mechanical strength, and durability. Here, we propose a layer-by-layer assembly of cellulose nanofiber (CNF)/Ti

Desirable mechanical strength and self-healing performance are very important to highly sensitive and stretchable sensors to meet their practical applications. However, balancing these two key performance parameters is still a great challenge. Herein, we present a simple, large-scale, and cost-efficient route to fabricate autonomously self-healing strain sensors with satisfactory mechanical properties. Specifically, ion-intercalated mechanical milling was utilized to realize the large-scale preparation of graphene nanosheets (GNs). Then, a well-organized GN-nanostructured network was constructed in a rubber matrix based on interfacial metal-ligand coordination. The resultant nanocomposites show desirable mechanical properties (∼5 times higher than that of control sample without interfacial coordination), excellent self-healing performance (even healable in various harsh conditions, for example, underwater, at subzero temperature or exposed in acidic and alkaline conditions), and ultrahigh sensitivity (gauge factor ≈ 45 573.1). The elaborately designed strain sensors offer a feasible approach for the scalable production of self-healing strain-sensing devices, making it promising for further applications, including artificial skin, smart robotics, and other electrical devices.

Carbon aerogels are suffering from moderate specific capacitance and inferior energy density for the as-fabricated electric double-layer capacitors. Meanwhile, such aerogels are limited by mechanical brittleness and traditional process of high-cost templates and unsustainable precursors. Herein mechanically-robust and compressible carbon aerogels were readily fabricated by low-temperature lyophilization of the frozen aqueous suspension of bamboo cellulose nanofibers in liquid nitrogen followed by high-temperature pyrolysis. Free-standing carbon aerogels were further coated through in-situ oxidative polymerization of pyrrole, producing homogeneous core-sheath carbon aerogel/polypyrrole (PPy@CA) composites. The symmetrical supercapacitor using the PPy@CA electrodes delivers a specific capacitance of 268.5 F g−1 at 0.5 A g−1 and an energy density of 23.8 Wh Kg−1 at the power density of 450.4 W kg−1. At an elevated current density of 10 A g−1, the energy density remains as high as 19.6 Wh kg−1 at the highest power density of 8018.2 W kg−1. Moreover, the supercapacitor retains 88% of its initial capacitance after running 10,000 cycles at 10 A g−1. These excellent performances for PPy@CA are attributable to their electrically-conductive 3D carbon frameworks and interconnective porous channels capable of efficient diffusion of electrolyte ions, fast transport of electrons, and preserving structural stability. Such active nanocomposites are currently pursued as supercapacitor electrodes due to the synergistic effect between high power density of CAs and high energy density of pseudo-capacitive PPy.

Flexible and wearable supercapacitor (SC) fabrics have received considerable research interests recently. However, their high hydrophobicity, poor conductivity, inferior capacitance, and low energy density remain a bottleneck to be solved. Herein, a highly flexible and conductive carbonized cotton fabric (CCF) covered by a unique nanostructured Ni(OH)2 layer is fabricated via a facile high-temperature carbonization process, followed by an electrochemical deposition (ED) treatment. The nanostructured Ni(OH)2 greatly improves the hydrophilicity of CCF to promote electrolyte penetration and offers abundant electroactive sites, leading to dramatically increased specific capacitance and operating potential window (OPW). The resultant Ni(OH)2@CCF is then applied as the electrode for an aqueous symmetric SC device. This device has an OPW of 1.4 V and exhibits a high specific capacitance of 131.43 F g–1 at the current density of 0.25 A g–1 with a high energy density (35.78 Wh kg–1 at a power density of 0.35 kW kg...

Animal skins possess multiple fascinating functions for acclimatization and survival, including displaying colorful patterns, wound healing and detecting various stimuli. Although tremendous progress in skin-mimicking materials has been achieved, it remains a great challenge for them to integrate these attractive properties into one single material system. Here, inspired by the cephalopod skin, we describe a mechanoluminescence material with skin-like self-healing and sensing properties based on nanostructured self-healable supramolecular elastomer composites. The resulting multifunctional material exhibits polychrome fluorescence and dazzling patterns under stretching, and is capable of sensing environmental variations including stress and humidity. Besides, benefiting from the excellent self-healing properties of the supramolecular elastomer matrix with synergistic interactions of dynamic-covalent and hydrogen bonds, this material can self-recover both strain-responsive fluorescence and sensing ability at ambient temperature after break. This bio-inspired multifunctional material demonstrates great potential for applications in future optoelectronics, encryption devices, electronic skins and intelligent robot fields.

Lightweight conductive graphene@polyurethane (PU) sponge with unique 3D structure and prominent piezoresistivity is a promising candidate for highly sensitive pressure sensor. However, the poor mechanical properties of PU skeleton and the use of toxic reductant for the reduction of graphene oxide (GO) greatly hampered its large-scale application. Here, we demonstrated for the first time that aramid nanofibers (ANFs) can be used as desirable building blocks to endow the layer-by-layer (LBL) assembled GO@PU nanocomposites with excellent mechanical properties. At the same time, the potassium hydroxide existed in ANFs solution could in-situ reduce the GO without extra reductants. The as-prepared rGO@PU/ANFs conductive nanocomposites exhibited excellent piezoresistive sensitivity and repeatability, enabling the nanocomposites to serve as flexible sensors for the application of human motions monitoring. This work opens up new opportunity for the facile fabrication of high performance graphene-based piezoresistive sensors and other electronic devices.

Three-dimensional (3D) printing technology with satisfactory speed and accuracy has been a powerful force in biomaterial processing. Early studies on 3D printing of biomaterials mainly focused on their biocompatibility and cellular viability while rarely attempted to produce robust specimens. Nonetheless, the biomedical applications of polymers can be severely limited by their inherently weak mechanical properties particularly in bone tissue engineering. In this study, continuous liquid interface production (CLIP) is applied to construct 3D objects of nano-hydroxyapatite (n-HA) filled polymeric biomaterials with complex architectures. Notably, the bioactive and osteoconductive n-HA endows the 3D prints of poly(ethyleneglycol)diacrylate (PEGDA) composites with a high compression strength of 6.5 ± 1.4 MPa, about 342% improvement over neat PEGDA. This work demonstrates the first successful attempt on CLIP 3D printing of n-HA nanocomposites, providing a feasible, cost-effective and patient-specific solution to various fields in the biomedical industry.