In this study, polyvinyl alcohol (PVA), graphene oxide (GO), and sodium lignosulfonate (LS) are used to modify the surface of carbon fibers (CFs), and the impacts of these substances on the properties of composites are studied. It is found that PVA introduction can improve the wettability and interfacial compatibility of CFs, which is beneficial to improve the bonding strength between CFs and epoxy (EP) resin matrix. Due to its unique two-dimensional structure and abundant functional groups, GO can form stable chemical bonds with the surface of CFs, further improving the mechanical performance and thermal stability of the CF-based composites. Meanwhile, LS can enhance the activity of the CF surface, reduce surface energy and improve dispersibility. Under the synergistic effects of PVA, GO, and LS, the interfacial shear strength, impact strength, and fracture toughness of CF-PVA-LS/GO/EP composites are increased by 143.2 %, 97.0 %, and 481.4 %, respectively. Furthermore, the stress distribution during the fracture evolution of the composites is analyzed using ABAQUS software, and the effects of all three substances on the composites are explored. This study provides a new pathway for the surface modification of high-performance CF composites and offers important value references for the design of CF/EP composites.

Flexible strain sensors hold considerable potential for human-machine interaction and health monitoring, yet conventional single-network systems often suffer from brittleness, limited durability, and insufficient multifunctionality. Herein, a multifunctional polyacrylamide (PAAm)/polyvinyl alcohol (PVA) composite hydrogel incorporating tannic acid-modified lignin (TA@AL) is developed via a simple one-pot polymerization followed by Fe3+ post-impregnation. A hierarchical triple-network structure is constructed, consisting of (i) a covalent PAAm backbone, (ii) a physically interpenetrated PVA network stabilized by hydrogen bonding, and (iii) a dynamic metal-phenol coordination network between TA@AL and Fe3+. Owing to this synergistic architecture, the hydrogel exhibits a high tensile strength of 115 kPa, a fracture strain of ∼900%, and a toughness of 0.45 MJ m-3, together with robust adhesion and high ionic conductivity (0.75 S m-1). Density functional theory (DFTD3) calculations further reveal the coordination energetics between FeCl3 and different polymer ligands, demonstrating that multidentate coordination in the PAAm/PVA/TA system provides strong yet dynamic binding, which underpins efficient energy dissipation and mechanical robustness. Benefiting from the coupled mechanical and electrical properties, the hydrogel functions as a high-performance strain sensor with high sensitivity, fast response, and excellent cycling stability, enabling accurate detection of both large-amplitude joint motions and subtle physiological signals such as swallowing and handwriting. This work not only offers an effective strategy for lignin valorization but also provides a molecular-to-macroscopic design framework for high-strength, conductive, and multifunctional hydrogels for wearable and biomedical applications.

Developing efficient surface modification strategies to enhance interfacial adhesion has become a crucial research direction for fully exploiting the mechanical and functional capabilities of carbon fiber-reinforced polymer (CFRP) composites. In this study, based on the concept of organic-inorganic multi-scale heterogeneous structure design, we demonstrated the process of assembling organic tannic acid/(3-aminopropyl) triethoxysilane (TA/A) three-dimensional(3D) nanospheres and inorganic MXene (MX) two-dimensional(2D) nanosheets onto the surface of carbon fiber (CF) to prepare high-performance MX-TA/A-modified CF/epoxy (CF/EP) composites. The spherical TA/A nanostructures not only increase the surface roughness of CFs, generating mechanical interlocking with the EP matrix, but also provide a hierarchical interface that enhances stress distribution under external loading. Moreover, the incorporation of MX nanosheets introduces a high-aspect-ratio nanostructure with abundant surface terminations, providing additional active sites for interfacial interactions and serving as a mechanical reinforcement that resists interfacial debonding. The TA/A–MX assembly strategy provides a versatile and sustainable route for designing multifunctional interfacial layers on CFs. It effectively integrates the benefits of polyphenol adhesion chemistry, silane coupling, and 2D nanomaterial reinforcement. This approach not only enhances the interfacial bonding strength and toughness of CFRP composites but also offers a generalizable platform for fabricating high-performance fiber-reinforced materials for aerospace, automotive, and structural applications.

To enhance the mechanical performance of carbon fiber (CF)-reinforced polymer composites, an elaborate multi-scale "soft-rigid" interfacial architecture was constructed by the sequential self-assembly of carboxymethyl cellulose (CMC), MXene (MX), and chitosan (CS) on the CF surface. This hierarchical structure markedly improves the wettability and surface roughness of CFs, thereby strengthening interfacial chemical bonding and mechanical interlocking with the epoxy (EP) matrix. Moreover, the multi-scale soft-rigid interface functions as a modulus-gradient transition layer, enabling more uniform stress distribution, suppressing stress concentration, buffering external loads, and inducing crack deflection and microcrack formation, which collectively enhance energy dissipation during fracture. As a result, the flexural modulus and interfacial shear strength of modified CF/EP composites are improved compared with unsized CF composites and commercial sized CFs, which are increased by 69.6%, 43.3% (to 48.0 GPa) and 165.7%, 73.1% (to 116.1 MPa), respectively. This bioinspired interfacial engineering strategy provides a promising and scalable route for the fabrication of high-strength and high-toughness CF/EP structural materials.

To address the rising need for multifunctional integration in core materials for flexible wearable electronics, this study presents a composite hydrogel that combines high mechanical strength, sensitive sensing capabilities, and efficient electromagnetic interference (EMI) shielding. By incorporating hydroxylated multi-walled carbon nanotubes (OH-MWCNTs) as nano-conductive fillers into a polyacrylamide/quaternary ammonium chitosan (PAM/HACC) dual-network matrix, a multifunctional composite material was successfully fabricated. The PAM/ HACC dual-network structure provides remarkable mechanical properties through synergistic energy dissipation, achieving a tensile strength of 435 kPa and an elongation at break exceeding 2500%. Uniformly dispersed OH-MWCNTs establish a robust and stable three-dimensional conductive network within the hydrogel, enabling the material to function as a highly sensitive strain sensor (with GF up to 16.04 at 200%-300%) for reliably monitoring diverse human physiological activities-from large-scale joint movements to subtle motions such as speech and coughing. Moreover, the hydrogel exhibits an electromagnetic shielding effectiveness exceeding 30 dB, and the average effectiveness is stable at more than 25 dB across the X-band (8.2-12.4 GHz). This work offers an innovative and promising material platform for next-generation flexible electronics that integrate sensing and shielding functionalities.

Conductive hydrogels have been extensively investigated and demonstrate promising applications in wearable and flexible sensors. However, their broader implementation in this field is hindered by the insufficient strain sensitivity, susceptibility to mechanical damage with limited self-recovery, and inadequate adhesion to human skin. Herein, we present a multifunctional MXene/TA@CNC electronic hydrogel patch (MTC e-patch) by integrating highly conductive two-dimensional (2D) transition metal carbides (MXene) and tannic acid-coated carboxylated cellulose nanocrystals (TA@CNC) with polyvinyl alcohol and borax. And dynamic threedimensional (3D) network is formed through synergistic dynamic hydrogen bonding and dynamic borate ester linkages. The incorporation of TA@CNC effectively prevents the oxidation of MXene, thereby extending the operational lifespan of hydrogels. The flexible covalent crosslinked network, combined with the rigidity of TA@CNC, imparts the MTC e-patch with excellent electrical conductivity (1.62 S/m), superior mechanical strength (approximate to 1.35 MPa, 930 %), robust adhesiveness (approximate to 28 kPa), and high self-healing capability (92 %). The rapid (161 ms) and sensitive (Gauge factor = 4.39) sensing performance of the developed wearable sensor enables the precise detection of subtle human motions, such as swallowing, throat vibrations during speech, and pen strokes during writing. Even when damaged, the sensor continues to provide stable signal output, demonstrating significant potential for applications in smart wearables, electronic skins, and human-machine interfaces.

Interfacial adhesion directly affects the mechanical properties of basalt fiber (BF)-reinforced polymer composites. To construct a more superior interphase between BFs and epoxy resin (EP) than a weak interphase of the unmodified BF/EP, we propose a hierarchical sandwich structure consisting of sodium hydroxide-activated boron nitride (BNOH), polyethyleneimine (PEI), and MXene (MX, Ti3C2Tx) through facile layer-by-layer self-assembly. The fabricated BNOH/P/MX sandwich structure (P denoting "PEI") can synergistically improve the interface adhesion by enhancing the mechanical interlocking and chemical bonding of the composites. When the composites reinforced by BF-BNOH/P/MX subject to the external loading, flexible PEI molecules allow twodimensional (2D) rigid BNOH and MX nanosheets to slip at the interface by uncurling the molecular chains, dissipating a great amount of energy during the fracture progress. Meanwhile, the hierarchical BNOH/P/MX sandwich structure acts as an excellent interface and possesses multistage gradient modulus and wider thickness, uniformly and efficiently transferring the stress from the EP matrix to BFs. The interfacial shear strength, impact strength, and fracture toughness of BF-BNOH/P/MX-reinforced EP composite are substantially improved by 45.9 %, 60.6 %, and 148.9 %, respectively, compared with bare BF-based composites. This study can provide valuable references and inspirations for designing and constructing high-quality interfaces for high-strength and hightoughness BF structural materials, taking advantage of 2D materials.

A variety of nanomaterials and highly active materials have been successfully applied to modify carbon fiber (CFs) to acquire high-performance CF-reinforced polymer composites (CFRPs). In this study, we report vacuum filtration-mediated layer-by-layer assembly of MXene (MX) and carboxymethyl cellulose (CMC) on the surface of CFs, to create novel CF-MX/CMC hybrid materials with rigid-flexible bilayers on CFs. The hybrid bilayer structure of MX/CMC provides robust interfacial adhesion between CFs and epoxy (EP) resin, effectively transfer stress by dissipate energy, resulting in substantial enhancements to the interface performance of the final CF-MX/CMC/EP composites. The interfacial shear strength and interlaminar shear strength of the created CF-MX/CMC/EP composites are improved significantly compared with those of unmodified CF/EP composites. The work presents new strategies for regulating the interfacial properties of CFRPs through simple, economical, and pollution-free techniques, revealing high potential for the design, regulation, and engineering application of MX- and CMC-modified CFRPs.

In this study, we report the construction of a multistage rigid and flexible structure using boron nitride (BN) and MXene (MX, Ti3C2Tx) nanosheets through the conjugation with (3-aminopropyl) triethoxysilane (APTES). The created structure is further utilized to modify basalt fibers (BFs) to obtain BF/epoxy resin (BF/EP) composites via a simple coating process. The rigid two-dimensional materials (2DMs), BN and MX, significantly enhance the roughness of the BF surface, while the silane (APTES) acts as a flexible bridge for linking BFs, BN, and MX. Consequently, the constructed multistage rigid and flexible structure synergistically enhances the strength and toughness of the composite through effective mechanical interlocking, chemical bonding, and multistage energy dissipation. Meanwhile, this complex structure prevents the stress concentration and promotes uniform stress transfer between BFs and EP. This study provides a promising strategy to construct an effective interface layer and achieve high-performance BF/EP composites by introducing 2DMs and a silane linker.

Interfacial adhesion determines the mechanical performance of the carbon fibers-reinforced polymers composites (CFRPs), and different bonding interactions could lead to different degrees of interfacial adhesion and me-chanical properties of CFRPs. In order to survey specific influence of different bonding interactions on the interface bonding, further boost the mechanical properties of CFRPs, MXene is decorated onto carbon fiber (CF) surface via van der Waals force or hydrogen bonds (CF-v-MXene), ionic bonds (CF-i-MXene), and covalent bonds (CF-c-MXene), respectively. Besides, detailed interaction mechanisms of various bonding interactions are also comprehensively investigated. The results indicate that the introduction of MXene is obviously efficient for improving the interface adhesion and mechanical properties of CF/epoxy (CF/EP) composites, and the com-posites reinforced by CF-c-MXene exhibit the optimal properties. Tremendous improvements of 90.1 % and 110.3 % for the impact strength and interfacial shear strength (IFSS) are achieved compared with the composites reinforced by the unsized CF. The microscopic interfacial structure and fracture failure mode are further observed and analyzed to explore the enhancement mechanisms. This work provides effective guidance and reference for the application of MXene and other similar 2D layered materials, such as Transition Metal Dichalcogenides (TMDCs), to design and manufacture high-quality interface for CFRPs with excellent interfacial and mechanical properties.

Different micro-configurations of graphene oxide (GO) nanosheets on the carbon fiber (CF) surface, including the distribution and size, endow CF-GO enhanced microstructure and physiochemical characteristics of the CF/epoxy (CF/EP) composites. In order to investigate the relationship between the GO micro-configuration and the interfacial adhesion of the CF/EP, here, polyether imide (PEI)-GO heterogeneous reinforcement was grafted onto the CF surface (CF-PEI-GO) by precisely modulating the mass ratio of CFs to GO. The micro-configuration and properties of the CF-PEI-GO hybrids, together with the thickness and modulus variation of the interface layer are investigated, in order to make certain on the enhancement mechanisms of both interfacial and mechanical performances. Optimal performances of the CF-PEI-GO/EP composites are achieved with a CF/GO mass ratio of 40:1. The uniformly “upright” distribution of moderate-size GO on the CF surface induces a synergistic effect of improved mechanical interlocking, chemical bonding, high wettability, and effective interface adhesion, which are stemmed from higher surface roughness, more active functional groups, higher surface energy, and wider interface thickness with gradient descent modulus. This work presents a valid, practical strategy to precisely control the interfacial adhesion of the CF/EP composites by adjusting the micro-configuration of 2D materials on the fiber surface.

With the huge demand and rapid development of portable, intelligent, and microscale equipment, more stringent requirements are put forward for the thickness, performance, and cost of the electromagnetic interference (EMI) shielding materials. In this work, flexible and ultrathin MXene/nanofiber (MX/NF) composite films with excellent EMI shielding performance are designed and fabricated by self-stacked assembly through vacuumassisted filtration. 2D MXene nanosheets are utilized as conductive materials to construct a conductive path, and cellulose nanofibers (CENF) and carbon nanofibers (CANF) are applied to improve the flexibility and supportability of the designed composite films. When the mass ratio of MXene to CANF-CENF is 4:1 and the thickness of the composite film is 11 mu m, the shielding effectiveness (SE) of the EMI film reaches 43.1 dB. In addition, the ranking efficiency product (REP) sustainability analysis is performed for the MX/NF-0.8 and three other EMI films, and it is found that the MX/NF-0.8 composite film possesses the largest REP value of 0.787. Besides, it exhibits the advantages in terms of degradability and shielding performance. The presented flexible, ultrathin EMI shielding films with layer-stacked structure reveal great application potential in the field of EMI shielding and could be appliable for wearable intelligent devices.

Two-dimensional (2D) MXene (MX) and silane coupling agents are increasingly used to modify carbon materials for the fabrication of composite functional materials, which exhibit enhanced electrical, optical, and mechanical properties due to the synergistic effects of both MX and silane. We demonstrate the modification of carbon fibers (CFs) with MX and three different kinds of silane coupling agents, including 3-aminopropyltriethoxysilane, 3-glycidyloxypropyldimethoxymethylsilane, and 3-mercaptopropyltriethoxysilane, which are named as CF-MX@N, CF-MX@O, and CF-MX@S, respectively, and further prepare the CF-MX@silane/epoxy (EP) composites. The utilized silane coupling agents serve as bridges between MX and CFs, forming CF-MX@silane composites. Through comparative analysis, it is found that the CF-MX@S composites form a strong interface phase through covalent bonds, significantly enhancing the interface compatibility and revealing strong interface adhesion. The interfacial shear strength of the molded CF-MX@S/EP composites increases to 119.7 MPa, with an 173.9% enhancement comparing to unmodified composites. This work can offer useful guidance and reference for selecting appropriate silane coupling agent to modify CFs with 2D materials to form high-performance composite materials.Highlights Silane coupling agents are used as bridges to graft MXene-modified CFs The surface modification of CFs is achieved by a simple one-step approach Excellent interfacial phase is constructed through forming strong covalent bonds Microstructure and failure interface are responsible to interface strengthen.

The determination and adsorption of Hg2+ in/from a solution system is of great significance in environmental monitoring and remediation. In this study, we present the design and synthesis of peptide nanosheets (PNSs) functionalized with Fe3O4 magnetic nanoparticles (MNPs) and develop a simple, fast, and naked-eye observable colorimetric detection nanoplatform and a sustainable adsorption system for Hg2+. For the aims, a functional peptide molecule with motif-designed sequence, Fmoc-FKKGSHC, is used for the formation of PNSs with uniform size by tailoring the molecular self-assembly process. The created PNSs are further modified with -COOH-functionalized Fe3O4 (c-Fe3O4) MNPs through electrostatic interaction to form two-dimensional (2D) PNSs/c-Fe3O4 nanocomposites. Due to the unique nanozymatic activity of c-Fe3O4 and specific interactions between PNSs and Hg2+, the fabricated PNSs/c-Fe3O4 nanocomposites not only exhibit high anti-interference ability towards Hg2+ detection with high sensitivity and a low detection limit of 2.52 nM but also reveal good adsorption efficiency towards Hg2+ at a concentration of 0-100 ppm as a recyclable and sustainable adsorption material. This study not only presents green strategies to prepare functional peptide nanomaterials via regulating molecular self-assembly and biomimetic synthesis but also inspires potential applications of peptide-inspired nanomaterials in biological analysis and environmental monitoring.

Molecular design and biomimetic/bioinspired synthesis provide facile ways for the construction of functional nanomaterials for various applications. Peptide-based functional nanomaterials with ideal morphology and functions can be obtained through the design of peptide sequences, regulation of molecular self-assembly, bio-mimetic synthesis, and hybridization with other functional nanoscale building blocks. In this review, we present a progress report on the combination of peptide self-assembly and biomimetic synthesis for tailoring the structure and functions of peptide nanomaterials aiming to biomedical applications. Through structural and functional tailoring, peptide-based nanomaterials exhibit enhanced chemical, physical, and biological properties, which greatly promote their potential applications in biomedical fields, including biosensors, bioimaging, photo-thermal/photodynamic therapy, tissue engineering, drug/gene delivery, and antibacterial materials. This interesting research topic could be promoted by discovering more peptide sequences, investigating the self-assembly behavior of peptides, simulating the internal driving factors of peptide self-assembly, and accurately controlling the functions of peptides to prepare peptide-based hybrid nanomaterials, which are beneficial to design and fabricate functional biocompatible nanosystems for clinical biomedicine.

The interface quality is crucial for the properties of carbon fiber-reinforced polymer- matrix composites (CFRPs). In order to improve the interfacial and mechanical properties of CFRPs, a superior gradient modulus interfacial microstructure is constructed on the carbon fiber (CF) surface by chemically grafting a self-assembly carboxyl-terminated hyperbranched polymer (HP-COOH). A monofilament debonding test, a short beam shear test, an impact test and a dynamic mechanical thermal analysis (DMTA) were conducted to investigate the properties of the modified composite. Prominent improvements of 79.6% for the interfacial shear strength, 51.5% for the interlaminar shear strength, and 49.2% for the impact strength, as well as superior heat-resistance properties are achieved for composites with the gradient modulus interface over those of the untreated CF composites. The mechanism for performance improvement is mainly attributed to the enhanced CF surface energy, mechanical interlocking, and chemical bonding interactions. In particular, an atomic force microscopy (AFM) test proved that the gradient modulus interfacial microstructure formed by HP–COOH could widen the interface layer thickness and buffer the sharp variations in the modulus from CF to resin, thereby transmitting an external force and reducing the stress concentration. This work provides a facile and efficient strategy for constructing a superior and versatile interface for high- performance composites.

An optimized "rigid-flexible" structure with multistage gradient modulus was constructed on carbon fiber (CF) surface via chemical grafting using "flexible" polyethyleneimine (PEI) and "rigid" polydopamine (PDA) between "rigid" CF and "flexible" epoxy (EP) to elaborate a double alternant "rigid-flexible" structure for simultaneously strengthening and toughening CF/EP composites. PDA and PEI polymers can greatly enhance the roughness and wettability of CF surfaces, further strengthening the mechanical interlocking and chemical interactions between CFs and epoxy. Besides, the "rigid-flexible" structure endows the interface with a gradient transition modulus, which could uniformly transfer internal stress and effectively avoid the stress concentration. Moreover, the double alternant "rigid-flexible" could buffer the external loading, induce more micro cracks and propagation paths and, thereby, consume more energy during the destruction of the composite. The interfacial shear strength, interlaminar shear strength, impact strength increased by 80.2%, 23.5% and 167.2%, and the fracture toughness improved by 227.2%, compared with those of the unmodified CF composite, respectively. This creative strategy and design afford a promising guidance for the preparation and production of advanced CF/EP structural materials with high strength and toughness.

A novel hyperbranched 2,2-bis-(hydroxymethyl) propionic acid polyester-32-hydroxyl (hyperbranched polymer) was selected to graft onto a carbon fiber (CF) surface to enhance the interfacial properties of carbon fiber/epoxy composites. The homogeneous distribution of hyperbranched polymers on the CF surface could increase the wettability, mechanical interlocking and chemical interaction between the CF and epoxy resin. Compared to untreated carbon fiber, the interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and impact strength of the modified carbon fiber/epoxy composite increased by 78.2%, 40.9% and 39.2%, respectively. Furthermore, the thermal stability of the composites improved. The interfacial strengthening mechanism was also investigated by in-depth analysis of the fracture interface microstructure. Interfacial property enhancement was related to the decrease in stress concentration due to the introduction of the gradient modulus interphase induced by the grafted hyperbranched polymer layer.