The rapid development of modern advanced electronic systems has created a pressing need for multifunctional polymer composites that can withstand external adversities such as electromagnetic waves, flames, and mechanical stresses. Although these requirements can be satisfied by incorporating different types of fillers, high filler loadings often lead to issues such as poor processability and increased material costs. Herein, a multifunctional polyamide‐6 composite is introduced using a carbon‐fiber flame‐retardant hybrid filler to design a next‐generation electromagnetic interference (EMI) shielding system. Based on the synergistic effect of the functionality and structural arrangement of these fillers in the composite, the EMI shielding system demonstrates high EMI shielding performance, improved mechanical properties, and excellent flame retardancy despite the low filler content. The scalability and multifunctionality of the proposed system highlight its potential for use in next‐generation applications, such as electric vehicles, aerospace, and 5G/6G telecommunications.

Recently, MXenes have attracted considerable attention owing to their unique physical and chemical properties. Construction of MXenes to three-dimensional (3D) porous aerogel structures can play a critical role in realizing the profound implications of MXenes, especially for environmental remediation. Nevertheless, developing mechanically robust MXene-based aerogels with reversible compressibility under harsh conditions, such as liquid environments, remains challenging due to the insufficient interfacial strength between MXene nanosheets. Herein, 3D porous MXene-based nanocomposite aerogels are developed by dual physical and chemical crosslinking strategy with poly(vinyl alcohol) and formaldehyde in this study. The developed MXene-based nanocomposite aerogels with designed interfacial engineering exhibit outstanding structural stability and extremely high reversible compressibility up to 98% strain as well as unprecedented mechanical durability (2000 cycles at 50% strain) in water environment. Moreover, the aerogels show adaptable compressibility when exposed to different solvents, which is explained with the Hansen solubility parameter. Thanks to their high compressibility in water, the robust MXene-based aerogels exhibit excellent methylene blue adsorption performance (adsorption capacity of 117.87 mg·g −1 ) and superior recycling efficiency (89.48% at the 3 rd cycle). The porous MXene-based nanocomposite aerogels are also demonstrated with outstanding thermal insulation capability. Therefore, by synergistically taking their porous structure and super elasticity in liquid environment, the MXene-based aerogels show great promise in diverse applications including adsorption and separation, wastewater purification desalination, and thermal management.

The advances in modern intelligent electronic systems have a pressing need for smart electromagnetic interference (EMI) shielding capabilities in a frequency-selective manner to choose which electromagnetic waves in a certain range to be blocked. Herein, we present multilayered EMI shielding composites that can provide selective on–off characteristics for specific frequency ranges across a broad spectrum. The composites are composed of outermost dielectric layers and conductive interlayers fabricated via solution printing, wherein hexagonal boron nitride (BN) and silver-coated BN particles are embedded, respectively. The EMI shielding frequency range and on–off selectivity are controllable by varying the configuration of the composite structure in terms of the BN content and the number of composite layers, providing different interstitial spaces between the fillers and interfacial dielectric properties. Furthermore, the optimal combination of these layers permits excellent combinatorial properties of EMI shielding effectiveness (32–62 dB), thermal conductivity (7.61 W/m·K), and electrical insulation (4.03 kV/mm) in the through-plane direction. The developed composites and their synthetic pathways have enormous potential for tailored material design and flexible system integration in next-generation EMI shielding technologies.

Very recently, the additive manufacturing of lignin-based composites has shown promising results toward the sustainable development of green materials. However, the high brittleness and poor 3D printability of the composites restrict their printing, caused by lignin's weak compatibility with polymers and its high viscosity. In this study, a high-performance, printable lignin-based polylactic acid (PLA) composite was investigated through copolymerizing 2-ethylhexyl acrylate at the interface. It was shown that 10 wt% modified lignin (e-lignin) composites exhibit significantly enhanced toughness from 1.16 to 3.84 MJ/m3 and also impact energy from 2.12 to 6.36 KJ/m2 relative to the pure PLA. The responsible toughening effect was interpreted by plasticization and the bridging effect of e-Lignin. The low melt viscosity of the dispersed e-Lignin phase caused local thermo-rheological relaxation and promotes the mobility of PLA molecular chains, showing desirable melt viscosity for fused deposition modeling 3D printing. Notable that the adhesion strength between deposited layers during additive manufacturing was increased due to high interfacial diffusion of composites, where an approximately 138% improvement of weld energy was achieved in 10 wt% e-lignin composites compared to those of pure PLA. This study shows the great promise to utilize lignin extracted natural materials particularly in additive manufacturing by replacing petroleum-based thermoplastics.

The incorporation of porous structures into films and coatings can transform their properties for applications in optics, separation, electronics, and energy generation and storage. Packing nanoparticles (NPs) is a versatile approach for fabricating nanoporous films with a tunable structure and properties. The mechanical fragility of NP packing-based films and coatings, however, significantly impedes their widespread utilization. Although infiltrating a polymer into the interstices of these NP packings has been shown to enhance their mechanical durability, this method completely eliminates the porosity of the structures, compromising their properties and functionality. This study presents a new approach to fabricate highly loaded porous nanocomposite films with a gradient in the refractive index by infiltrating subsaturating amounts of poly(methyl methacrylate) (PMMA) into disordered packings of hollow silica NPs. We demonstrate that dual porosity is a critical feature that enhances their antireflection (AR) and mechanical properties. The hollow cores of NPs prevent a substantial increase in the refractive index of the resulting films. Moreover, the interparticle voids allow for mechanical reinforcement to occur when the NP packings are infiltrated with PMMA, making them even more suitable for AR coatings. The refractive index and gradient across the nanocomposites can be tailored by adjusting the amount of PMMA infiltrated into the NP packing, the shape of hollow NPs, and the annealing time. The nanocomposite coatings with a continuous gradient in refractive index exhibit excellent AR properties and enhanced mechanical durability. Combined with the unique structural tunability afforded by the dual porosity, this approach provides a scalable and effective way to create robust and graded nanoporous structures for various applications.

Twisted and coiled actuators (TCAs), which are light but capable of producing significant power, were developed in recent times. After their introduction, there have been numerous improvements in performance, including development of techniques such as actuation strain and heating methods. However, the development of robots using TCA is still in its early stages. In this study, a bionic arm driven by TCAs was developed for light and flexible operation. The aim of this study was to gain a foothold in the future of robot development using TCA, which is considered as the appropriate artificial muscle. The main developments were with regard to the design (from actuator design to system design), system configuration for control, and control method. First, a process technology for repeatedly manufacturing TCA, which can be used practically and delivers sufficient performance, was developed. Based on the developed actuator, a joint was designed to move the elbow and hand. The final bionic arm was developed by integrating the TCA, pulley joint, and control system. It moved the elbow up to 100° and allowed the hand to move in three degrees of freedom. Using the control method for each joint, we were able to show the movement by using the hand and elbow.

Global oil spill and water contamination issues are urgently requiring the development of next-generation oil sorbent materials that may desirably have the functionalities of reusability and biodegradability without generating secondary pollutions. Herein, a novel oil sorbent is introduced that could be practically useful in the cleanup for oils from contaminated water with low-cost and sustainability. The oil sorbent is composed of a polyurethane (PU) foam incorporated with hydrophobized lignin particles up to 40 wt%, in which the lignin is acetylated to increase the compatibility with the matrix and sorption capacity; for crude oil, the composite foam with an acetylated lignin content of 20 wt% shows increased absorption capacity of 8.06 g/g compared to the neat PU foam capacity of 4.51 g/g. The absorbed oil can be easily reclaimed simply by squeezing the foam with a good recyclability, which is maintained 97.9% and 92.3% of the mass-based sorption capacity even after 50 cycles for olive oil and crude oil, respectively. The developed composite foams and the methodology have enormous potential as a promising solution for the cleanup of organic contaminants.

Cerium oxide nanoparticles in the size of Ca. 100 nm usually have a degree of crystallinity over 95% and the ratio of Ce3+/Ce4+ at around 40%, which are ascribed to the intrinsic characteristics of atomic hybridization to form a cubic fluorite lattice structure. Therefore, the common form of cerium oxide nanoparticles has high crystallinity and large crystallite size. In this paper, we compared the nanoclustered cerium oxide nanoparticles with the high crystalline ones in terms of surface morphology, crystallinity, surface activity, and oxide removal rates. The NC-ceria and the CF-ceria nanoparticles having similar sizes of 108 and 117 nm with standard deviations of 10.3 and 22.5 nm, respectively. As a novel form of abrasive, the NC-ceria is spherical with crystallite size, Lc = 4.4 nm; crystallinity, Xc = 70.5%, which is quite different from the CF-ceria (Lc = 45.5 nm, Xc = 95.8%). These two different crystal structure provided different properties of Ce3+/Ce4+ ratio and the OH− concentration as 48.4 and 69.4% than CF-ceria as 39.5 and 47.3%, respectively, seemingly due to the propound number of unbound atoms on the surface. As a result, the SiO2-removal rate of NC-ceria is achieved as 8904 Å/min, which is much higher than that of CF-ceria at 3823 Å/min. Overall, the nanocluster ceria abrasive demonstrates a physically-soft and chemically-active nature, giving excellent SiO2-removal capability and great potential in scratch suppression in CMP processing.

Although polyetherimide (PEI) has attracted attention owing to its good dielectric properties, superior mechanical properties, and thermal/chemical stabilities, there is still a lack of methodology to fabricate PEI films in desired shapes directly on devices. In this study, a dispenser printing method to fabricate sophisticated 2D PEI structures is introduced. As dispenser printing is a solution-based process, PEI ink is prepared by dissolving PEI in N-methyl pyrrolidone (NMP). The printing conditions are controlled by optimizing the pneumatic pressure and viscosity of the inks with various ratios of PEI and NMP, followed by a two-step heat treatment to develop fine PEI films. The dielectric constant of the PEI film increases from 2.28 to 2.61 with the corresponding secondary heating time of 1-5 h, which is much lower than the theoretical value owing to the free volume and loosely entangled polymer chains generated from the shear forces in printing and solvent evaporation. Furthermore, the film exhibits anisotropic mechanical properties in different printing directions, stemming from the alignment effect of the polymer molecules. It is believed that the developed PEI films and the facile methodology can be diversely tuned to provide new insights into material utilization, further extending the application fields.

As there are gradually increasing interests in polymeric energy-absorbing materials to reduce unwanted noise/vibration, and enhance impact resistance in structural applications, considerable efforts have been empirically made to improve energy-absorbing properties. However, there has been no detail understanding of the energy-absorbing mechanisms of particulate composites, thereby showing a trade-off between toughness and modulus/strength. Therefore, by coupling modeling and experimental efforts, this study systematically explores the thermoplastic polymer particle toughening and ways to overcome the typical compromise in energy-absorbing composites. Polyamide-nylon 6 particulate polycarbonate composite was carefully designed for achieving extraordinary energy absorption with the uncompromised properties. The debonding, fracture toughness and yieldings were semi-empirically investigated to reveal fracture energy contributions. It was found that the mainly responsible energy-absorbing mechanism was matrix yielding (48.28%), which results from the particle debonding and significantly contribute to crack propagations. This study could provide new solutions for the energy-absorbing composites without any comprome in modulus/strength.

A non-enzymatic electrochemical sensor, based on the electrode of a chitosan-derived carbon foam, has been successfully developed for the detection of glutamate. Attributed to the chelation of Cu ions and glutamate molecules, the glutamate could be detected in an amperometric way by means of the redox reactions of chelation compounds, which outperform the traditional enzymatic sensors. Moreover, due to the large electroactive surface area and effective electron transportation of the porous carbon foam, a remarkable electrochemical sensitivity up to 1.9 × 104 μA/mM∙cm2 and a broad-spectrum detection range from nM to mM scale have been achieved, which is two-orders of magnitude higher and one magnitude broader than the best reported values thus far. Furthermore, our reported glutamate detection system also demonstrates a desirable anti-interference ability as well as a durable stability. The experimental revelations show that the Cu ions chelation-assisted electrochemical sensor with carbon foam electrode has significant potential for an easy fabricating, enzyme-free, broad-spectrum, sensitive, anti-interfering, and stable glutamate-sensing platform.

Depolymerized suberin derivatives (DSDs) isolated from cork powder, the industrial waste, were used for the synthesis of an ecofriendly biopolyester (pDSDs) syntactic foam along with expandable microspheres (EMs). Its potential for replacing the conventional petroleum-based polymer was demonstrated, and renewable resources were suggested. In this study, the optimum amount of glycerol (5.77 wt %) to meet the stoichiometry in DSDs polyesterification was determined with H-1 NMR. By engineering EMs, the cell size and porosity of syntactic foams were controllable, and the mechanical properties were characterized. The specific compressive modulus of this syntactic foam was raised up to 66% when EMs were filled from 20 to 30 wt %. Viscoelastic properties of syntactic foams were characterized by varying the weight fractions of EMs and the EMs' size. It should be noted that the tan delta for syntactic foams with DSDs was found to be greater than the one of natural cork (up to 124%) from -50 to 80 degrees C. Encouragingly, the biopolyester syntactic foams synthesized with suberin extracted from the cork powder can offer a new way to reduce carbon footprint by recycling industrial waste and replacing conventional petroleum-based polymeric foams.

As electromagnetic (EM) pollution continues to increase, electromagnetic interference (EMI) shielding materials have been intensively evaluated in terms of two main shielding mechanisms of reflection and absorption. Since the shielding effectiveness (SE) is represented in the logarithmic scale and in a coupled way of transmission (SET), absorption (SEA), and reflection (SER), often there is a misinterpretation that the EM wave reflectors are regarded as EM wave-absorbing materials. Surprisingly, we found that many materials reported as an EM wave absorber in the literature provide, in fact, less than 50% of EM wave-absorbing capability, i.e., over 50% of EM wave-reflecting feature. According to the theory and definition of EMI SE, the absorption-dominant EMI shielding materials should have the ratio of absorption to incident energy (A) as A > 0.5, which corresponds to a necessary condition that SER < 3.01 dB. The SER subsequently gives SEA in relation to SET. Using this criterion, we classified the EMI shielding materials with their shielding mechanism. The proposed methodology provides significant insight into the evaluation and development of EMI shielding materials.

Zn-metal anodes are promising candidates for aqueous Zn-ion batteries (ZIBs) owing to their high theoretical capacity, good electrochemical reversibility, and the natural abundance of zinc. However, dendrite growth and corrosion of Zn anodes during cycling hinder the practical application of ZIBs. In this study, we built robust zincophilic channels based on carboxylated hollow ceria (CHC) nanostructures on a Zn anode. With a robust three-dimensional nanostructure, the zincophilic-channel interfaces on the Zn anode present highly stable Zn plating/stripping cycling stability for up to 2000 h at a high current density of 3 mA cm(-2). The resulting CHC@Zn//MnO2 full cell exhibits enhanced electrochemical performance.

A composite system with embedded bimodal-sized hybrid core–shell spheres is reported for electromagnetic interference (EMI) shielding applications, of which the shells are either wave-diffuse reflecting nickel/gold or wave-absorbing graphene.

Many air filtration technologies have been used to solve the environmental issues of fine and ultrafine dust particles, which have been raised over the past decades. Many other filtration technologies have been developed, while high-efficiency particulate arrestance (HEPA) is widely used recently due to its high efficiency. However, the HEPA filter has some limitations, such as high pressure drop, nonrecyclability, and most importantly, short lifetime. Regarding other types of air filters, electrostatic filters require a two-stage process (i.e., charging and polarization) of particles before filtration, whereas electroadhesion air filters could capture both polar and nonpolar particles without a two-stage process. The dust-holding capacity allows the quantitative analysis of the areal adhesion amount to be conducted. In this study, three different kinds of particles of fine dust, microcrystalline cellulose, and Teflon were tested. A model equation of the areal adhesion amount was also developed as a function of boundary edge length, voltage, and the dielectric constant of each material and allowed the areal adhesion amount of fine dust particles to be maximized, which is well above those of the HEPA filter and electrostatic filter. The optical images clearly showed that the dielectric polarization of polar particles was stronger than that of nonpolar particles.

MXene (Ti2C) modified by 3-aminopropyl triethoxysilane was grafted onto carbon fiber (CF) surface in an attempt to improve interfacial properties in continuous CF reinforced epoxy composites. X-ray photoelectron spectroscopy, scanning electron microscopy, and dynamic contact angle test were employed to characterize the effect of the grafted Ti2C on the interfacial properties. A single fiber fragmentation test together with acoustic emission testing was performed to identify the interface failure mode and also determine the interfacial shear strength (IFSS). The interlaminar shear strength (ILSS) of the laminates was also evaluated with three-point beam testing. It was experimentally observed that Ti2C sheets were uniformly grafted on the fiber surface with covalent bonding. It could provide not only the increase of the CF surface roughness but also an excellent opportunity to create plenty of the polar functional groups thereby leading to a greater surface energy of the CF. The IFSS and ILSS of Ti2C modified CF composites were enhanced by ~78% and ~28% increase, respectively, compared to ones of unsized CF composites.

Nowadays, MXenes have attracted significant attention owing to their extraordinary chemical and physical properties. However, it remains challenge to keep their outstanding properties in polymeric composites. Herein, by mimicking nacre with their unique layered brick-and-mortar microstructures, MXene-based nanocomposite films are developed with biocompatible polymer, xanthan. The free-standing nanocomposite films exhibit high electrical conductivity with high tensile strength (11,530 +/- 176 S m(-1) and 116.48 +/- 6.43 MPa for the film with 67 wt% of MXene). Equally importantly, failure strain and toughness of the film with 50 wt% of MXene are dramatically increased to 6.4 and 12.7 times greater than those of neat MXene film. The substantially improved mechanical properties and high electrical conductivity of the nanocomposite films arise from the synergistic by marrying bioinspired layered brick-and-mortar structures with extraordinary material properties of MXene and the best feature of xanthan. The highly electrically conductive and mechanically robust MXene-xanthan composite films were further investigated for electromagnetic interference (EMI) shielding and Joule heating capabilities. It was demonstrated that the nanocomposite films can exhibit the exceptionally high absolute shielding effectiveness (SSE/t = 24,464.8 and 14,490.1 dB cm(2) g(-1) respectively for the films with 80 wt% and 67 wt% of MXene) and also uniform temperature distribution with high energy transduction efficiency and high thermal stability for Joule heating performance. Therefore, the nacre-inspired MXene-xanthan nanocomposite films can show the great promise for the use in a wide range of engineering applications such as electronics or biomedical devices. This is particularly true when it requires multiple functions including EMI shielding, thermal management, and mechanical robustness.

Recently, two-dimensional (2D) MXenes have emerged as filler materials for electromagnetic interference (EMI) shielding polymer composites due to their extraordinary electrical conductivity, high surface area, hydrophilic nature, and flexibility. Three-dimensional (3D) Printing with MXenes appears to be a new paradigm for manufacturing EMI shielding structures, where complex and specific 3D architecture is often required. In this study, composite inks incorporating 2D Ti3C2Tx MXenes with highly thixotropic properties were developed for the liquid deposition modeling (LDM) 3D Printing method. The use of these inks enabled the fabrication of semitransparent EMI shielding 3D architectures. The 3D-Printed EMI shields exhibited excellent EMI shielding effectiveness (EMI SE), particularly in the X-band (similar to 231 dB/mm) and semi-transparency (54.61%) in the visible light range. Moreover, excellent thermal management capability with highly anisotropic thermal conductivity (anisotropic index: 3.6) was achieved through 3D Printing. It is anticipated that the approach developed in this study has potential for the fabrication of advanced EMI shielding architecture with good thermal management capability for various applications, for example, precision wireless communication devices using variable frequencies with multiple channels, autonomous driving vehicles, and the Internet of Things (IoT).

Reducing the thickness of transparent paper without losing its outstanding optical haze and transmittance remains a challenge due to their trade-off relationship. Herein, an all-cellulose transparent paper composed of cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) is developed by electrophoretic deposition (EPD) thanks to the good film-forming ability of the CMC. The thickness of the paper can be controlled in the range of 2.4-30 mu m depending on the applied voltage and deposition time. The optical properties and mechanical strength are adjusted by the sonication time and the ratio between CNF and CMC, since the CNF works as a light-scattering source and mechanical reinforcement agent. Consequently, a robust all-cellulose paper with a thickness of 10 mu m exhibiting high transmittance (up to 96%) and haze (up to 89%) is successfully fabricated. As our paper has competitive optical properties despite the thinner thickness than other reported all-cellulose transparent and hazy paper, we achieved the highest optical haze and transmittance values per unit thickness. We believe that this all-cellulose paper with outstanding optical properties has great potential to be applied to many fields that include flexible devices, environmentally friendly electronics, optoelectronics, and other functional devices.