Multifunctional Composites Research Articles

Efficient adsorption of waste carbon nanotube by polyacrylamide gel to form wrinkled core-shell particles towards multifunctional composites for EMI shielding and sensing

Waste carbon nanotubes (CNTs) have always been a potential threat to the environment and biological health. However, the efficient recycling and utilization of CNTs has received little attention. Here, we used chemically cross-linked polyacrylamide (PAM) particles to adsorb waste CNTs in water to prepare PAM@CNT core-shell particles, which were blended with thermoplastic styrene-butadiene rubber (SBS) to prepare flexible composites. The concentration of residual CNTs in the supernatant was less than 3.5 μg mL−1, which meets the safety standards for discharge. The unique core-shell structure enables the composites with a thickness of 1 mm to exhibit high electromagnetic interference shielding effectiveness (53.3 dB) and low reflectivity (1.4 dB) at 30 wt% CNT content. In addition, at a CNT content of 10 wt%, the composites exhibit superior sensing properties concerning strain and solvents. Moreover, the composites prepared from different sources of waste CNTs have the same sensing properties. This work provides an effective strategy for the highly efficient recycling of waste CNTs for the preparation of green, high-performance multifunctional polymer composites for EMI shielding, human motion and solvent leakage monitoring, and solvent category differentiation.

Multifunctional 3D carbon fiber/epoxy braided composites with excellent compression performance and electromagnetic interference shielding

The multifunctional composites with electromagnetic interference (EMI) shielding performance and mechanical property are in urgent demand. In this work, the carbon fibers reinforced 3D braided preforms (3DBPs) were fabricated by a four-step braiding method. Then, the 3D braided composites (3DBCs) were prepared via vacuum assisted resin transfer molding technique. The establishment of a comprehensive 3D conductive network conferred upon the 3DBCs an exemplary EMI shielding efficiency of 54.01 dB in the X-band. Furthermore, the 3DBPs served the reinforcing function, attaining an exceptional compressive strength of 211.48 MPa at a density of 1.37 g/cm3. It is of great significance to apply the 3D braiding technology to develop EMI shielding composites to realize the structure-function integration.

Impact of stacking sequence on the thermal and electrical properties of Poly (aryl ether ketone)/glassfiber/buckypaper composites

AbstractThe current market's imperative demand necessitates the research and development of advanced polymer composites, especially those incorporating nanofillers. Carbon nanotubes, in particular, have attracted significant attention within research and development for their potential in creating multifunctional composites. This study aims to evaluate the impact of incorporating carbon nanotube buckypapers (BP) on the thermal and electrical properties of poly (aryl ether ketone) (PAEK)/glass fiber (GF) composites. The BP was prepared through vacuum filtration and integrated into PAEK/GF composites with varying stacking sequences, followed by hot compression processing. The degradation behavior of the laminates was investigated using thermogravimetric analysis (TGA). The viscoelastic properties, evaluated by dynamic mechanical analysis (DMA), suggested an increase in stiffness with the inclusion of BP in two of the analyzed stacking sequences. Thermal conductivity, measured via the pulse laser method, showed results comparable to the base laminate (0.153 W/m·K). Meanwhile, electrical conductivity, assessed using the four‐point probe method in the in‐plane direction, revealed semiconductor properties, achieving a mean value of 3.162 S/cm for one of the samples, indicating electrical anisotropy within the multifunctional composite material.

Sustainable and multifunctional polyurethane green composites with renewable materials

Polyurethane materials are characterised by an ever-expanding range of application possibilities due to their versatility. Currently, the management of leftovers as well as post-production and post-consumer waste for the production of biocomposites is one of the most obvious, effective and profitable solutions. Due to the renewable nature of biofillers such as cellulose, lignin, and chitin, their use to obtain composite polyurethane elastomers is a real perspective for the dissemination of more environmentally friendly materials and, at the same time, contributes to additional economic profit. The key aspect for further development of the polyurethane/biopolymer biocomposite concept is to fulfil of a number of currently functioning industry standards, mainly those regarding functional properties. In the presented research, an attempt to obtain advanced polyurethane elastomers with the addition of biopolymers (cellulose, lignin, and chitin) was conducted for the first time. The innovative biocomposites obtained in this way were characterised by good processing parameters (processing times, density) and improved functional properties compared to the standard without the addition of fillers (abrasion resistance, tensile strength, contact angle, hardness). Due to the above-mentioned facts, the described biocomposites can be successfully used for the production of multifunctional elastomeric materials with a wide range of potential applications. Moreover, it is worth noting that the management of waste materials in this way will reduce production costs while indirectly contributing to the protection of the natural environment.Graphical abstract

Multi‐Interfacial Heterostructure Design of Carbon Fiber/Silicone Rubber‐Oriented Composites for Microwave Absorption and Thermal Management

AbstractIn order to ensure the operation and longevity of electronic devices, the design of multifunctional composites integrating microwave absorption (MA) and thermal conduction has become the key to solving the problem. However, the superior MA properties and thermal conductivity are usually incompatible in the blend system. In this study, a modified carbon fiber/silicone rubber‐oriented structure is designed based on the multiscale design concept of heterostructures with multiple interfaces. The forward deposition‐reverse growth mechanism is utilized at the microscopic level to construct multi‐interfacial heterogeneous structures on the surface of 1D carbon fibers (CFs). The magneto‐electric coupling network of the multi‐interfacial heterostructure induces interfacial polarization and enhances MA properties and heat transfer. Subsequently, the structural design of the modified CFs is carried out on a macroscopic scale using the ice template method. The directionally aligned modified CFs/silicone rubber aerogel composites are obtained by backfilling with silicone rubber (SR). The samples achieved an effective absorption bandwidth of 4.41 GHz and a maximum reflection loss of −42.29 dB with ultra‐thin thickness (1.3 mm). The thermal conductivity of the sample is improved to 200% compared to pure silicone rubber. The composites with directional alignment have promising applications in lightweight and flexible electronic packaging.

Ultra-hydrophobic Eucommia gum coating with temperature-responsive and shape-memory performance

The intelligent and multifunctional composites offer important applications in many fields. However, the fabrication of intelligent and multifunctional composites still faces limitations due to complicated processes, high costs, and restricted area coverage. Here, we present a new approach for creating a micro/nano-hybrid hierarchical Eucommia ulmoides gum (EUG) coating with outstanding superhydrophobic, temperature-responsive and shape-memory characteristics. The intelligent EUG coating prepared in this study can regulate the change and recovery of the microstructure of the coating surface by altering temperature and external force, thereby achieving control of the surface properties and memory performance of the coating. These EUG hydrophobic shape-memory coatings are obtained through the preparation of superhydrophobic sepiolite particles, spin coating, and chemical cross-linking processes. In addition to its performance advantages, the outstanding advantage of these composites is the simple and easy preparation process, regardless of the substrate surface topography. These novel superhydrophobic and temperature-responsive shape-memory EUG composites can achieve contact angle and thickness regulation. These superhydrophobic and temperature-responsive shape-memory EUG composites are highly expected to be applied in medical devices and intelligent textiles fields.

Fabrication of sea urchin shaped polyaniline-modified magnetic microporous organic network for efficient extraction of non-steroidal anti-inflammatory drugs from animal-derived food samples

In this work, a novel polyaniline-modified magnetic microporous organic network (MMON-PANI) composite was fabricated for effective magnetic solid phase extraction (MSPE) of five typical nonsteroidal anti-inflammatory drugs (NSAIDs) from animal-derived food samples before high performance liquid chromatography (HPLC) detection. The core-shell sea urchin shaped MMON-PANI integrates the merits of Fe3O4, MON, and PANI, exhibiting large specific surface area, rapid magnetic responsiveness, good stability, and multiple binding sites to NSAIDs. Convenient and effective extraction of trace NSAIDs from chicken, beef and pork samples is realized on MMON-PANI via the synergetic π-π, hydrogen bonding, hydrophobic, and electrostatic interactions. Under optimal conditions, the MMON-PANI-MSPE-HPLC-UV method exhibits wide linear ranges (0.2–1000 μg L−1), low limits of detection (0.07–1.7 μg L−1), good precisions (intraday and inter-day RSDs < 5.4 %, n = 3), large enrichment factors (98.6–99.9), and less adsorbent consumption (3 mg). The extraction mechanism and selectivity of MMON-PANI are also evaluated in detail. This work proves the incorporation of PANI onto MMON is an efficient way to promote NSAIDs enrichment and provides a new strategy to synthesize multifunctional MON-based composites in sample pretreatment.

Mo2Ti2C3 and PTFE synergistically functionalized corrosion-resistant, thermally conductive, super abrasion-resistant epoxy resin composite coating

Epoxy resin (EP) matrix composites are a widely used polymer-based protective coating material. However, the low lubricity leads to frictional wear problems that make their large-scale development and application a serious challenge. Based on this, a multifunctional composite coating (MPT-EP) with low wear, high lubricity, high thermal conductivity, and corrosion resistance was prepared by introducing polytetrafluoroethylene (PTFE) and lamellar Mo2Ti2C3 as a composite lubricant into epoxy resin matrix using a simple solvent dispersion method. The results showed that the introduction of the composite lubricant resulted in enhanced hardness and mechanical properties of the composite coating. Compared with the single epoxy resin coating (0.31), the friction coefficient (COF) of the composite coating was only 0.22, and the friction surface did not show obvious abrasion marks. The surface temperature of the composite coating was up to 51.4 °C when it was placed on a hot bench at 60 °C for 60 s. In addition, the COF of the composite coating did not change significantly after being immersed in acid, alkali and salt solutions. Therefore, the Mo2Ti2C3-induced multifunctional epoxy resin matrix composites have important application potential and research value in the field of ultra-wear-resistant and high lubrication protective coatings.

Multifunctional bamboo-based fiber composites fabricated by assembling 3D network structures of bamboo and spatial distribution of silver nanoparticles

Bamboo-based composites have been commonly used in engineering applications as a renewable carbon recycling material. Despite its prevalent use, bamboo possesses inherent drawbacks, including flammability, moisture absorption, and susceptibility to microbial corrosion, significantly diminishing the service life of the composites as outdoor materials. Hence, a straightforward synthesis strategy was used to prepare multifunctional bamboo-based fiber composites (BFCs). This involved constructing a three-dimensional (3D) network interface within the bamboo via the combination of mechanical and chemical pretreatments, including alkali treatment, in-situ reduction, impregnation, lamination, and hot pressing. The obtained dense structure, together with the successful incorporation of functional AgNPs, enables the composites to exhibit outstanding mechanical properties (328 MPa cm3 g−1 of tensile specific strength). Moreover, the bamboo-based composite shows good flame retardancy (self-extinguishing within 5 s after ignition), improved thermal conductivity (0.258 W m−1 K−1), a self-cleaning ability, and commendable antibacterial activity against two common pathogenic bacterial (E. coli and S. aureus). This versatile bamboo-based fiber composite material holds promise for diverse outdoor applications, including roofs, wall panels, outdoor flooring, etc.

Research of a new multifunctional composition against the corrosion of the internal surface of oil pipelines in the mine shaft

For the first time, a chloroprene reagent (named as Z-1) has been used against corrosion in various aggressive environments under laboratory conditions. The corrosion protection properties of the reagent Z-1 have been studied in formation waters taken from oil wells No. 2646, 33151, 4012, 31193 and 33016 in operation at Balakhani Oil OGED. Samples made of Ct3 and P-105 brand steels with dimensions of 42155 mm have been used during the tests. Experiments have been performed under dynamic conditions at room temperature for six and twenty-four hours, and the corrosion rate has been determined by gravimetric method. During the experiments, concentrations of 10, 15, 20 and 25 mg/l of Z-1 composition were used. The analysis of results from numerous experiments conducted with both types of steel revealed that the optimal concentration of the composition is 25 mg/l. The protection efficiency of the composition Z-1 in the formation waters of the abovementioned oil wells during the six-hour experiment was as follows: for Ct3 samples, it ranged from 75% to 94%, 75% to 97%, 76% to 98%, 72% to 94%, and 68% to 87%, respectively, while for P-105 steel samples, it ranged from 76% to 96%, 72% to 92%, 73% to 85%, 70% to 90%, and 72% to 96%, respectively. During 24-hour corrosion tests, the protection efficiency of the composition Z-1 was 73–92%, 74–96%, 75–97%, 70–92%, and 66–85% for Ct3 steel samples and 75–94%, 70–91%, 72–83%, 68–89%, and 71–95% for P-105 steel samples, respectively.

New Zein Protein Composites with High Performance in Phosphate Removal, Intrinsic Antibacterial, and Drug Delivery Capabilities.

Herein, poly(N-(4-aminophenyl)methacrylamide)-carbon nano-onions [abbreviated as PAPMA-CNOs (f-CNOs)] integrated gallic acid cross-linked zein composite fibers (ZG/f-CNOs) were developed for the removal/recovery of phosphate from wastewater along with controlled drug delivery and intrinsic antibacterial characteristics. The composite fibers were produced by Forcespinning followed by a heat-pressure technique. The obtained ZG/f-CNOs composite fibers presented several favorable characteristics of nanoadsorbents and drug carriers. The composite fibers exhibited excellent adsorption capabilities for phosphate ions. The adsorption assessment demonstrated that composite fibers process highly selective sequestration of phosphate ions from polluted water, even in the presence of competing anions. The ZG/f-CNOs composite fibers presented a maximum phosphate adsorption capacity (qmax) of 2500 mg/g at pH 7.0. This represents the most efficient phosphate adsorption system among all of the reported nanocomposites to date. The isotherm studies and adsorption kinetics of the adsorbent showed that the adsorption experiments followed the pseudo-second-order and Langmuir isotherm model (R2 = 0.9999). After 13 adsorption/desorption cycles, the adsorbent could still maintain its adsorption efficiency of 96-98% at pH 7.0 while maintaining stability under thermal and chemical conditions. The results mark significant progress in the design of composite fibers for removing phosphates from wastewater, potentially aiding in alleviating eutrophication effects. Owing to the f-CNOs incorporation, ZG/f-CNOs composite fibers exhibited controlled drug delivery. An antibiotic azithromycin drug-encapsulated composite fibers presented a pH-mediated drug release in a controlled manner over 18 days. Furthermore, the composite fibers displayed excellent antibacterial efficiency against Gram-positive and Gram-negative bacteria without causing resistance. In addition, zein composite fibers showed augmented mechanical properties due to the presence of f-CNOs within the zein matrix. Nonetheless, the robust zein composite fibers with inherent stimuli-responsive drug delivery, antibacterial properties, and phosphate adsorption properties can be considered promising multifunctional composites for biomedical applications and environmental remediation.

Silver Coated Multifunctional Liquid Crystalline Elastomer Polymeric Composites as Electro-Responsive and Piezo-Resistive Artificial Muscles.

Liquid crystalline elastomers (LCEs) are a class of shape-changing polymers with exceptional mechanical properties and potential as artificial muscles/polymer actuators. In this study, multifunctional LCE actuators with strain sensing and joule heating responsivity are developed. LCEs are successfully synthesized using the thiol-ene two-staged michael addition polymerization (TMAP) method. The LCE films are further functionalized via sequential polydopamine (PDA) and silver electroless coating. It is found that the PDA coating enabled the anchoring of the Ag particles to the LCE, thereby enabling the electrical conductivity of the Ag-LCEs (<0.1 Ω cm-1). The studies confirm that the Ag/PDA coated LCEs can sense up to ≈30% strain, sense their own actuation strokes, and actuate at a rate of 1.83% s-1 while lifting a weight ≈50 times its mass in response to a 12V 2A DC current.

Electrical conductivity of multifunctional cementitious composites reinforced by graphene derivatives: A finite element-based computational micromechanics model

Graphene derivatives (GDs) are known for their considerable conductivity and electron mobility, making them promising candidates for developing electrically conductive cementitious composites (CCs). Consequently, CCs reinforced with GDs (CRGDs) can serve a variety of applications in the construction industry. Despite several experimental studies on the conductivity of CRGDs, finite element (FE) models have rarely been developed to investigate the conductivity of CRGDs. Previous FE models primarily focused on one-dimensional fillers like carbon nanotubes within polymeric matrices, overlooking the distinctive anisotropic behaviour of GDs in cementitious matrices. This study introduces a computational micromechanics model (CMM), integrating the representative elementary volume (REV) concept with FE analysis, to investigate the electrical conductivity of CRGDs. This model is particularly noted for its computational efficiency, as it converts the problem dimensions from 3D to 2D while ensuring an acceptable degree of accuracy. The CMM captures the anisotropic conductivity of GDs and includes critical conductivity mechanisms such as conductive pathways, the tunnelling effect, and field emission. Subsequently, REV size sensitivity analysis is performed to ensure the statistical relevance of the REV, followed by the model's validation against experimental data from the literature. Afterwards, the model's sensitivity analysis clarifies how different parameters, including the constituent properties, influence prediction results. The sensitivity analysis results suggest that the aspect ratio of GDs has considerable impacts on the electrical conductivity and the percolation threshold of CRGDs. Ultimately, this study aims to provide insights into the optimization and design of electrically conductive CRGDs and lay the foundation for future research in this area.

Multifunctional Polymer Composites for Automatable Induction Heating with Subsequent Temperature Verification

Manipulating ferromagnetic particles using an alternating current (AC) magnetic field is a versatile method for quick, local, and on‐demand heat generation. These particles can be incorporated into various matrices as heating elements. Their heat release can be controlled by adjusting process or material parameters. Herein, a proof‐of‐concept for a flexible polymer composite with customizable magnetically triggered heat release due to prior object identification via fluorescence readout is presented. The maximum temperature resulting from this process can be determined through a second fluorescence readout ex post. This novel combination of functionalities results from the synergistic interaction of inductively heatable magnetic supraparticles (SPs) and luminescent communicating SPs in one polydimethylsiloxane composite. The surface of the composite can be heated to the maximum temperatures of choice in a range between 125 and 200 °C within 2 s. Heat release and temperature verification provide spatial resolution of millimeters. The identification signature and the working range of the temperature indication functionality of the composite are customizable by exploiting its modular material design. The temperature indication functionality of the composite offers spatial resolution and ex‐post readout at any point of interest, making it a versatile alternative to established optical thermometry methods.

Low Magnetic Field Induced Extrinsic Strains in Multifunctional Particulate Composites: An Interrupted Mechanical Strengthening in 3D-Printed Nanocomposites

Low Magnetic Field Induced Extrinsic Strains in Multifunctional Particulate Composites: An Interrupted Mechanical Strengthening in 3D-Printed Nanocomposites

Preparation of multifunctional flame-retardant wood composites by crosslinking chitosan-based polymers with phytic acid functionalized UiO-66-NH2

Bio-based composites can mitigate the pollution issues linked to petroleum-based materials due to their eco-friendly properties. On the other hand, bio-based functionalized metal-organic frameworks have gained attention in the field of flame retardants due to their multi-pathway flame retardant mechanism and environmentally friendly synthesis process. However, its application in wood industry is less. In this work, a novel functional adhesive and coating (ACS-MACS/PA-UiO66-NH2) was developed by using phosphorus-rich biomass phytate functionalized metal-organic framework (MOF) PA-UiO66-NH2 as a flame retardant and mixed with modified chitosan. Furthermore, using ACS-MACS/PA-UiO66-NH2 and three-layer wooden boards, a tight cross-linked network was formed through hot pressing dehydration and condensation reactions to prepare multifunctional wood composites. The experimental results indicated that the mechanical properties of the multifunctional wood composites are excellent. Additionally, these wood composites exhibit high levels of charring and graphitization, leading to excellent flame retardancy. The preparation process of these multifunctional wood composites is straightforward, and their excellent properties provide a foundation for the development of high-performance green composite materials.

Mechanically robust and electrically conductive nanofiber composites with enhanced interfacial interaction for strain sensing

Electrically conductive fiberfibre/fabric composites (ECFCs) are competitive candidates for use in wearable electronics. Therefore, it is essential to develop mechanically robust ECFC strain sensors with sensing performance. In this study, MXene assembly and hot-pressing were combined to prepare strong yet breathable ECFCs for strain and temperature sensing. Hydrogen bonding between MXene and polyurethane (PU) and ultrasonication-induced interfacial sintering were responsible for MXene nanosheets assembly on the PU nanofibers. MXene decoration made PU nanofibers electrically conductive, resulting in a conductive network. Hot-pressing improved interface adhesion among the conductive nanofibers. Thus, the mechanical properties of the nanofiber composites, including tensile strength, toughness and fracture energy, were enhanced. The nanofiber composites exhibited surface stability and durability. When the nanofiber composites were used as strain sensors, they showed breathability with a linear resistance response ranging from 1 % to 100 % and cycling stability. In addition, they produced stable sensing signals over 1000 cycles when a notch was present. They could also monitor temperature variations with a negative temperature coefficient (−0.146 %/°C). This study provides an interfacial regulation method for the preparation of multi-functional nanofiber composites with potential applications in flexible and wearable electronics.

Advanced polymer composites and polymer hybrids for cartilage tissue engineering

AbstractThe repair and regeneration of cartilage is a challenge for scientists and clinical surgery. Achieving cell adhesion and regeneration, anti‐inflammatory, lubrication, targeted drug delivery and controlled release simultaneously in cartilage treatment are the goals of researchers. Polymer composites and hybrids have the potential to realize above functions in cartilage tissue engineering. This review refers to cartilage injuries, current clinical techniques, and their benefits and limitations, focusing on the most relevant and state of art of advanced polymers for cartilage tissue engineering. The frontier applications of multifunctional polymer composites and hybrids in cartilage tissue engineering are discussed in depth, including polymer scaffold, polymer bio‐lubricant, and zwitterionic polymer for drug delivery and sustained drug release. A summary of comprehensive properties of polymers such as processability, mechanical properties, biocompatibility, biodegradability, hydrophilicity, cytotoxicity, etc., and their mechanisms are analyzed. Furthermore, some key challenges and outstanding concerns on polymer‐based materials for cartilage tissue engineering are presented followed by future perspectives.Highlights The state of art of advanced polymers for cartilage tissue engineering. The advanced bionic property and mechanism of polymer composites and hybrids. Polymers for scaffold, biolubricant, drug delivery, sustained drug release. Future perspectives on polymer composites, hybrids‐based cartilage materials.

Three-dimensional woven structural electromagnetic composite metamaterial with lightweight, anti-delaminate and in-phase reflection properties

Electromagnetic metamaterials are capable of tuning or controlling the transmission of the electromagnetic waves to realize high-performance microwave devices. However, the poor mechanical properties caused by the multi-layer structure limited its wide applications, especially in aircraft, satellites or high-speed vehicles. In this study, an electromagnetic metamaterial with in-phase reflection property was integrated into the three-dimensional (3D) woven composite to achieve the combination of unique electromagnetic properties and excellent mechanical properties on multi-functional composites. The 3D electromagnetic composite metamaterial was capable of reflecting electromagnetic waves from the antenna back lobe to the main lobe at 0° phase, resulting in the bandwidth of the test antenna increased from 0.6 GHz to 1.2 GHz, and the gain increased from 2.8 dB to 4.8 dB, an increase of 71.4 %. Owing to the tight physical bonding of binder yarn, 3D electromagnetic composite metamaterial exhibited excellent anti-delaminate performance and stable electromagnetic properties in 28 J impact. The impact damage threshold energy of the 3D electromagnetic composite metamaterial was significantly increased from 10 J to 30 J.

Discontinuous interleaving strategies for toughening, damage sensing and repair in multifunctional carbon fibre/epoxy composites

Thermoplastic interleaving is a well-established approach to toughen carbon fibre thermoset laminates, studied over the past five decades. Recently, it has been revisited to create functional smart composites with damage sensing and repair capabilities with a renewed focus on the sustainability and longevity of components. However, the introduction of thermoplastic films within the interlaminar region often lowers fibre volume fraction and performance at elevated temperature, while the addition of impermeable continuous films during manufacture may also limit compatible fabrication methods. Moreover, the incorporation of dielectric thermoplastic films inevitably reduces through-thickness electrical conductivity and prevents accurate damage sensing of delamination in carbon fibre laminates. In this study, strategies of using discontinuous interleaving to improve both fracture toughness and thermomechanical properties of carbon fibre epoxy laminates, with the ability to monitor delamination damage and restore mechanical properties after a short healing step have been explored. Both the interleaving design and the physical properties of the thermoplastic were assessed, which has not been addressed previously. Interleaving high molecular weight thermoplastic with decreasing interleaf width and distance between interleaf zones results in increased fracture toughness (+347 %), by creating a superior toughened interlaminar zone, forcing a migration of delamination into the intralaminar region. A repair efficiency of 77 % was achieved when using a lower molecular weight of thermoplastic; however, the lack of thermoplastic over the entire fracture surface area affects the repairing performance universally. Damage sensing and thermomechanical properties were significantly improved compared to continuous interleaving, demonstrating that discontinuous thermoplastic interleaving strategies offer a favourable combination of toughening, thermal performance and accurate damage sensing for multifunctional high-performance composites.