Synthesis of biopolymer blends nanocomposites embedded with mono-(Ag, Fe) and bi-(Ag-Fe) metallic nanoparticles using an eco-friendly approach for antimicrobial activities.

Plant-mediated solution casting is used to develop eco-friendly polymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) doped with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were studied to understand their electromagnetic interface (EMI) shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties. The Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) characterization techniques were used to examine the interactions between the polymers, the presence of silver and ferrous particles in the composites, the crystallinity shift, the surface morphology, the shape and size of the nanoparticles and the distribution of the nanoparticles in the composites. The FTIR spectra showed the interactions among the components of the composites. According to XRD spectra, the incorporation of nanoparticles into the PVA polymer significantly reduced the crystalline character of the polymer from 0.38 to 0.24 for the composition consisting of silver and iron nanoparticles in equal proportion. The results from SEM, EDX and XRD corroborate the presence of nanoparticle forms. The thermogravimetric analysis (TGA) tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites. The tensile properties showed that the addition of nanoparticles to the PVA/PVP polymer matrix increased its mechanical strength from 59.3 MPa to 85.5 MPa. We examined its efficacy against Escherichia coli, Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown enhanced, loss due to reflection, loss due to absorption, and the total EMI shielding efficiency at 8 GHz (X-band) and 16 GHz (Ku-band) frequency. All these results ratify, that these newly developed bio nanocomposites are most suitable in many applications, in EMI shielding, nanotechnology, and medical fields.

Stretchable, Transparent, and Ultra-Broadband Terahertz Shielding Thin Films Based on Wrinkled MXene Architectures.

With the increasing demand for terahertz (THz) technology in security inspection, medical imaging, and flexible electronics, there is a significant need for stretchable and transparent THz electromagnetic interference (EMI) shielding materials. Existing EMI shielding materials, like opaque metals and carbon-based films, face challenges in achieving both high transparency and high shielding efficiency (SE). Here, a wrinkled structure strategy was proposed to construct ultra-thin, stretchable, and transparent terahertz shielding MXene films, which possesses both isotropous wrinkles (height about 50 nm) and periodic wrinkles (height about 500 nm). Compared to flat film, the wrinkled MXene film (8 nm) demonstrates a remarkable 36.5% increase in SE within the THz band. The wrinkled MXene film exhibits an EMI SE of 21.1 dB at the thickness of 100 nm, and an average EMI SE/t of 700 dB µm-1 over the 0.1-10 THz. Theoretical calculations suggest that the wrinkled structure enhances the film's conductivity and surface plasmon resonances, resulting in an improved THz wave absorption. Additionally, the wrinkled structure enhances the MXene films' stretchability and stability. After bending and stretching (at 30% strain) cycles, the average THz transmittance of the wrinkled film is only 0.5% and 2.4%, respectively. The outstanding performances of the wrinkled MXene film make it a promising THz electromagnetic shielding materials for future smart windows and wearable electronics.

Robust ZTO reinforced AgNW hybrid transparent conductive thin films with absorption-enhanced EMI shielding property.

Evolving technology advancements has accelerated the pursuit of transparent conducting thin films (TCF) with superior mechanical properties, durability, efficient opto-electrical performance and substrate compatibility as a pivotal focus in the realm of flexible transparent electronics. With this concern, this work delves the fabrication of multilayer silver nanowire (AgNW) thin films reinforced by zinc tin oxide (ZTO) thin film encapsulation on polycarbonate substrates by the combination of sputtering and spin-coating techniques. Investigation on the influence of AgNW percolation networks on the opto-electrical properties of ZTO/AgNW/ZTO hybrid thin films was carried out. The impact of ZTO protective layers on the enhancement of electrical properties, adhesivity, flexibility and environmental stability of the multilayer TCF was elucidated. Additionally, to explore the compatibility of the fabricated TCF in integrated device and stealth applications, its electromagnetic interference (EMI) shielding property was investigated. The hybrid TCF showed 99.47% EMI shielding efficiency with absorption-dominant EMI shielding effectiveness of 22.7 dB in the x-band region. .

Hollow Metal-Organic Framework/MXene/Nanocellulose Composite Films for Giga/Terahertz Electromagnetic Shielding and Photothermal Conversion.

With the continuous advancement of communication technology, the escalating demand for electromagnetic shielding interference (EMI) materials with multifunctional and wideband EMI performance has become urgent. Controlling the electrical and magnetic components and designing the EMI material structure have attracted extensive interest, but remain a huge challenge. Herein, we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose (HMN) by alternating vacuum-assisted filtration process. The HMN composite films exhibit excellent EMI shielding effectiveness performance in the GHz frequency (66.8 dB at Ka-band) and THz frequency (114.6 dB at 0.1-4.0 THz). Besides, the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 THz. Moreover, HMN composite films show remarkable photothermal conversion performance, which can reach 104.6 °C under 2.0 Sun and 235.4 °C under 0.8 W cm-2, respectively. The unique micro- and macro-structural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance effect. These features make the HMN composite film a promising candidate for advanced EMI devices for future 6G communication and the protection of electronic equipment in cold environments.

A novel design of hip-stem with reduced strain-shielding.

The use of uncemented stems in hip arthroplasty has been increasing, even in osteoporotic patients. The major concerns of uncemented hip-stems, however, are peri-prosthetic fracture, thigh pain, and proximal femoral stress-/strain-shielding. In this study, a novel design of uncemented hip-stem is proposed that will reduce such concerns, improve osseointegration, and benefit both osteoporotic and arthritic patients. The stem has a central titanium alloy core surrounded by a set of radial buttresses that are partly porous titanium, as is the stem tip. The aim of the study was to investigate the mechanical behaviour of the proposed partly-porous design, examining load transfer in the short-term, and comparing its strain-shielding behaviour with a solid metal implant. The long-term effect of implant-induced bone remodelling was also simulated. Computed tomography based three-dimensional finite element models of an intact proximal femur, and the same femur implanted with the proposed design, were developed. Peak hip contact and major muscle forces corresponding to level-walking and stair climbing were applied. The proposed partly-porous design had approximately 50% lower strain-shielding than the solid-metal counterpart. Results of bone remodelling simulation indicated that only 16% of the total bone volume is subjected to reduction of bone density. Strain concentrations were observed in the bone around the stem-tip for both solid and porous implants; however, it was less prominent for the porous design. Lower strain-shielding and reduced bone resorption are advantageous for long-term fixation, and the reduced strain concentration around the stem-tip indicates a lower risk of peri-prosthetic fracture.

A Facile Approach to Produce Activated Carbon from Waste Textiles via Self-Purging Microwave Pyrolysis and FeCl3 Activation for Electromagnetic Shielding Applications.

This study aims to convert composite textile structures composed of nonwoven and woven fabrics produced from cotton-jute wastes into activated carbon textile structures and investigate the possibilities of using them for electromagnetic shielding applications. To this end, the novel contribution of this study is that it shows that directly carbonized nonwoven textile via self-purging microwave pyrolysis can provide Electromagnetic Interference (EMI) shielding without any processing, including cleaning. Textile carbonization is generally achieved with conventional heating methods, using inert gas and long processing times. In the present study, nonwoven fabric from cotton-jute waste was converted into an activated carbon textile structure in a shorter time via microwaves without inert gas. Due to its polar structure, FeCl3 has been used as a microwave absorbent, providing homogeneous heating in the microwave and acting as an activating agent to serve dual purposes in the carbonization process. The maximum surface area (789.9 m2/g) was obtained for 5% FeCl3. The carbonized composite textile structure has a maximum of 39.4 dB at 1 GHz of EMI shielding effectiveness for 10% FeCl3, which corresponds to an excellent grade for general use and a moderate grade for professional use, exceeding the acceptable range for industrial and commercial applications of 20 dB, according to FTTS-FA-003.

Flexible Sandwich-Shaped Cellulose Nanocrystals/Silver Nanowires/MXene Films Exhibit Efficient Electromagnetic-Shielding Interference Performance.

The electromagnetic pollution problem is becoming increasingly serious due to the speedy advance of electronic communication devices. There are broad application prospects for the development of flexible, wearable composite films with high electromagnetic interference (EMI)-shielding performance. The MX@AC composite films were prepared from MXene, silver nanowires (AgNWs) and cellulose nanocrystals (CNCs) with a sandwich structure. Benefiting from the upper and lower frame structure formed by winding 1D AgNWs and CNC, the tensile strength of the MX@AC was improved to 35 MPa (12.5 wt% CNC content) from 4 MPa (0 wt% CNC content). The high conductivity of MXene and AgNWs resulted in the MX@AC composite film conductivity up to 90,670 S/m, EMI SE for 90 dB, as well as SSE/t up to 7797 dB cm2 g-1. And the MX@AC composite film was tested for practical application, showing that it can effectively isolate electromagnetic waves in practical application.

EACVI survey on radiation exposure in interventional echocardiography.

AIMS: The European Association of Cardiovascular Imaging (EACVI) Scientific Initiatives Committee performed a global survey on radiation exposure in interventional echocardiography. The survey aimed to collect data on local practices for radioprotection in interventional echocardiography and to assess the awareness of echocardiography operators about radiation-related risks. METHODS AND RESULTS: A total of 258 interventional echocardiographers from 52 different countries (48% European) responded to the survey. One hundred twenty-two (47%) participants were women. Two-thirds (76%) of interventional echocardiographers worked in tertiary care/university hospitals. Interventional echocardiography was the main clinical activity for 34% of the survey participants. The median time spent in the cath-lab for the echocardiographic monitoring of structural heart procedures was 10 (5-20) hours/month. Despite this, only 28% of interventional echocardiographers received periodic training and certification in radioprotection and 72% of them did not know their annual radiation dose. The main adopted personal protection devices were lead aprons and thyroid collars (95% and 92% of use, respectively). Dedicated architectural protective shielding was not available for 33% of interventional echocardiographers. Nearly two-thirds of responders thought that the radiation exposure of interventional echocardiographers was higher than that of interventional cardiologists and 72% claimed for an improvement in the radioprotection measures. CONCLUSION: Radioprotection measures for interventional echocardiographers are widely variable across centres. Radioprotection devices are often underused by interventional echocardiographers, portending an increased radiation-related risk. International scientific societies working in the field should collaborate to endorse radioprotection training, promote reliable radiation dose assessment, and support the adoption of radioprotection shielding dedicated to interventional echocardiographers.

Wearable EMI Shielding Composite Films with Integrated Optimization of Electrical Safety, Biosafety and Thermal Safety.

Biomaterial-based flexible electromagnetic interference (EMI) shielding composite films are desirable in many applications of wearable electronic devices. However, much research focuses on improving the EMI shielding performance of materials, while optimizing the comprehensive safety of wearable EMI shielding materials has been neglected. Herein, wearable cellulose nanofiber@boron nitride nanosheet/silver nanowire/bacterial cellulose (CNF@BNNS/AgNW/BC) EMI shielding composite films with sandwich structure are fabricated via a simple sequential vacuum filtration method. For the first time, the electrical safety, biosafety, and thermal safety of EMI shielding materials are optimized integratedly. Since both sides of the sandwich structure contain CNF and BC electrical insulation layers, the CNF@BNNS/AgNW/BC composite films exhibit excellent electrical safety. Furthermore, benefiting from the AgNW conductive networks in the middle layer, the CNF@BNNS/AgNW/BC exhibit excellent EMI shielding effectiveness of 49.95 dB and ultra-fast response Joule heating performance. More importantly, the antibacterial property of AgNW ensures the biosafety of the composite films. Meanwhile, the AgNW and the CNF@BNNS layers synergistically enhance the thermal conductivity of the CNF@BNNS/AgNW/BC composite film, reaching a high value of 8.85 W m‒1 K‒1, which significantly enhances its thermal safety when used in miniaturized electronic device. This work offers new ideas for fabricating biomaterial-based EMI shielding composite films with high comprehensive safety.

Radio-Absorbing Magnetic Polymer Composites Based on Spinel Ferrites: A Review.

Ferrite-containing polymer composites are of great interest for the development of radar-absorbing and -shielding materials (RAMs and RSMs). The main objective of RAM and RSM development is to achieve a combination of efficient electromagnetic wave (EMW) absorption methods with advantageous technological and mechanical properties as well as acceptable weight and dimensions in the final product. This work deals with composite RAMs and RSMs containing spinel-structured ferrites. These materials are chosen since they can act as efficient RAMs in the form of ceramic plates and as fillers for radar-absorbing polymer composites (RAC) for electromagnetic radiation (EMR). Combining ferrites with conducting fillers can broaden the working frequency range of composite RAMs due to the activation of various absorption mechanisms. Ferrite-containing composites are the most efficient materials that can be used as the working media of RAMs and RSMs due to a combination of excellent dielectric and magnetic properties of ferrites. This work contains a brief review of the main theoretical standpoints on EMR interaction with materials, a comparison between the radar absorption properties of ferrites and ferrite-polymer composites and analysis of some phenomenological aspects of the radar absorption mechanisms in those composites.

Novel Polymer Composites for Lead-Free Shielding Applications.

Polymer nanocomposites have recently been introduced as lead-free shielding materials for use in medical and industrial applications. In this work, novel shielding materials were developed using low-density polyethylene (LDPE) mixed with four different filler materials. These four materials are cement, cement with iron oxide, cement with aluminum oxide, and cement with bismuth oxide. Different weight percentages were used including 5%, 15%, and 50% of the cement filler with LDPE. Furthermore, different weight percentages of different combinations of the filler materials were used including 2.5%, 7.5%, and 25% (i.e., cement and iron oxide, cement and aluminum oxide, cement and bismuth oxide) with LDPE. Bismuth oxide was a nanocomposite, and the remaining oxides were micro-composites. Characterization included structural properties, physical features, mechanical and thermal properties, and radiation shielding efficiency for the prepared composites. The results show that a clear improvement in the shielding efficiency was observed when the filler materials were added to the LDPE. The best result out of all these composites was obtained for the composites of bismuth oxide (25 wt.%) cement (25 wt.%) and LDPE (50 wt.%) which have the lowest measured mean free path (MFP) compared with pure LDPE. The comparison shows that the average MFP obtained from the experiments for all the eight energies used in this work was six times lower than the one for pure LDPE, reaching up to twelve times lower for 60 keV energy. The best result among all developed composites was observed for the ones with bismuth oxide at the highest weight percent 25%, which can block up to 78% of an X-ray.

Evaluating the effect of functionally graded materials on bone remodeling around dental implants.

OBJECTIVES: This study evaluates the potential for osseointegration and remodeling of customized dental implants made from Titanium-Hydroxyapatite Functionally Graded Material (Ti-HAP FGM) with optimized geometry, using the finite element method (FEM). METHODS: The study utilized CT scan images to model and assemble various geometrical designs of dental implants in a mandibular slice. The mechanical properties of Ti-HAP FGMs were computed by varying volume fractions (VF) of hydroxyapatite (0-20%), and a bone remodeling algorithm was used to evaluate the biomechanical characteristics of the ultimate bone configuration in the peri-implant tissue. RESULTS: The findings of the FEA reveal that osseointegration improves with changes in the density and mechanical properties of the bone surrounding Ti-HAP implants, which are influenced by the varying VF of hydroxyapatite in the FGM. SIGNIFICANCE: Increasing the hydroxyapatite fraction improves osseointegration, and appropriate length and diameter selection of Ti-HAP dental implants contribute to their stability and longevity.

Zeolitic imidazolate frameworks (ZIFs): Advanced nanostructured materials to enhance the functional performance of food packaging materials.

Zeolite imidazole framework (ZIF) materials are a class of metallic organic framework (MOF) materials that have several potential applications in the food and other industries. They consist of metal ions or clusters of metal ions coordinated with imidazole-based organic linkers, creating a three-dimensional solid structure with well-defined pores and channels. ZIFs possess several important features, including high porosity, tunable pore sizes, high surface areas, adjustable surface chemistries, and good stabilities. These characteristics make them highly versatile materials that can be used in a variety of applications, including smart and active food packaging. Based on their controllable compositions, dimensions, and pore sizes, the properties of ZIFs can be tailored for a diverse range of applications, including energy storage, sensing, separation, encapsulation, and catalysis. In this article, we focus on recent progress and potential applications of ZIFs in food packaging materials. Previous studies have shown that ZIFs can significantly improve the optical, mechanical, barrier, thermal, sustainability, and preservative properties of packaging materials. Moreover, ZIFs can be used as carriers to encapsulate, protect, and control the release of bioactive agents in packaging materials. ZIFs are capable of selectively adsorbing and releasing molecules based on their size, shape, and surface properties. These unique characteristics make them particularly suitable for smart or active food packaging applications. By selectively removing gases (such as oxygen, carbon dioxide, water, or ethylene) ZIFs can improve the shelf life and quality of packaged foods. In addition, they can be employed to control the growth of spoilage microorganisms and minimize oxidation reactions, thereby enhancing the freshness and extending the shelf life of foods. They may also be used to create sensors capable of detecting and indicating food spoilage. For instance, ZIFs that change color or release specific compounds when spoilage products are present can provide visual or chemical indications of food deterioration. This feature is especially valuable in ensuring the safety and quality of packaged food, as it enables consumers and retailers to easily identify spoiled products. ZIFs can be functionalized using various additives, including antioxidants, antimicrobials, pigments, and flavors, which can improve the preservative and sensory properties of packaged foods. Moreover, ZIF-based packaging materials offer sustainability benefits. Unlike traditional plastic packaging, ZIFs are biodegradable and can easily be disposed of without causing harm to the environment, thereby reducing the adverse effects of plastic waste materials. The application of ZIFs in smart/active food packaging offers exciting possibilities for enhancing the shelf life, quality, and safety of foods. With further research and development, ZIF-based packaging could become a sustainable alternative to plastic-based packaging in the food industry. An important aim of this review article is to stimulate further research on the development and application of ZIFs within food packaging materials.

Significant Reduction in Bone Density as Measured by Hounsfield Units in Patients with Ankylosing Spondylitis or Diffuse Idiopathic Skeletal Hyperostosis.

Background: Multisegmental pathologic autofusion occurs in patients with ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH). It may lead to reduced vertebral bone density due to stress shielding. Methods: This study aimed to determine the effects of autofusion on bone density by measuring Hounsfield units (HU) in the mobile and immobile spinal segments of patients with AS and DISH treated at a tertiary care center. The mean HU was calculated for five distinct regions-cranial adjacent mobile segment, cranial fused segment, mid-construct fused segment, caudal fused segment, and caudal adjacent mobile segment. Means for each region were compared using paired-sample t-tests. Multivariable regression was used to determine independent predictors of mid-fused segment HUs. Results: One hundred patients were included (mean age 76 ± 11 years, 74% male). The mean HU for the mid-construct fused segment (100, 95% CI [86, 113]) was significantly lower than both cranial and caudal fused segments (174 and 108, respectively; both p < 0.001), and cranial and caudal adjacent mobile segments (195 and 115, respectively; both p < 0.001). Multivariable regression showed the mid-construct HUs were predicted by history of smoking (-30 HU, p = 0.009). Conclusions: HUs were significantly reduced in the middle of long-segment autofusion, which was consistent with stress shielding. Such shielding may contribute to the diminution of vertebral bone integrity in AS/DISH patients and potentially increased fracture risk.

Tunable High-Performance Electromagnetic Interference Shielding of VO2 Nanowires-Based Composite.

The unique metal-insulator transition of VO2 is very suitable for dynamic electromagnetic (EM) regulation materials due to its sharp change in electrical conductivity. Here, we have developed an off/on switchable electromagnetic interference (EMI) shielding composite by interconnecting VO2 nanowires (NWs) in poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) to form conductive networks, resulting in outstanding performance at the X and Ku bands with maximum change values of 44.8 and 59.4 dB, respectively. The unique insulator-to-metal transition (IMT) of VO2 NWs has dominated the variation of polarization loss (εp″) and conductivity loss (εσ″) for the composites, which is the mechanism of EMI shielding switching between off and on states. Furthermore, the composite exhibits good cycling stability of the off/on switchable EMI shielding performance and has excellent mechanical properties, especially with 200 times abrasion resistance without obvious weight loss. This study provides a unique approach for dynamic switching of EM response with the potential to construct practical intelligent EM response systems for next-generation smart electromagnetic devices in various scenarios.

Effect of rare-earth oxide (Eu2O3) on the physical, mechanical, acoustic and radiation shielding properties of the CaO-Gd2O3-SiO2-B2O3 glasses.

In this study, we examined the effectiveness of europium-doped calcium gadolinium silicoborate glasses for determining their physical, mechanical, acoustic and radiation shielding properties with compositions of 25Gd2O3-10CaO-10SiO2-xEu2O3 -(55-x) B2O3 (where, x is 0.1, 0.2, 0.3, and 0.4 mol%). These glasses were theoretically analyzed using the Geant4 toolkit and Phy-X PSD software to calculate their performance for x-ray energies ranging from 0.2 to 1.2 MeV. The physical, acoustic and mechanical properties were determined using the Makishima-Mackenzie (MM) model. As the content of Eu2O3 increases, the density of the glasses also increases. As the amount of Eu2O3 increases, the mechanical properties decrease. This means that certain mechanical properties of the material may be negatively affected, resulting in a decreased ability to maintain structural integrity and resist deformation when exposed to radiation. The elastic modulus reflects the material's stiffness or rigidity, and a lower value indicates that the material is more prone to deformation when subjected to mechanical stress. Bulk and Young's moduli show a decreasing trend from 255.49 to 253.10 GPa and 368.20 to 366.50 GPa with increasing Eu+3 concentration in the glass samples. The LAC values of EuGd4 glass is much smaller when compared to the other glasses. The presence of gadolinium and europium compounds in the glass increases its ability to absorb radiation due to the elements of high atomic numbers. This is because the higher effective atomic number (Zeff) of these compounds enhances the glass of shielding capabilities against neutron and gamma rays, resulting in improved radiation protection.

Influence of implant base material on secondary bone healing: an in silico study.

The implant material at the fracture site influences fracture healing not only from biological perspective but also from mechanical perspective. Biodegradable implants such as magnesium (Mg) based alloys have shown faster secondary bone healing properties as compared to bioinert implants such as titanium (Ti). The general reasoning behind this is the benefit of Mg from biocompatibility perspectives. We studied the effect of Ti and Mg as base materials for implants from mechanical perspectives, where we focused on the displacements at the fracture site of the tibia and their influence on the stimulus for bone healing. We found out that in comparison to Ti, Mg implants have minimal stress shielding problem, only which led to better mechanical stimulus at the fracture site.

Supergravity-Steered Generic Manufacturing of Nanosheets-Embedded Nanocomposite Hydrogel with Highly Oriented, Heterogeneous Architecture.

Designing nanocomposite hydrogels with oriented nanosheets has emerged as a promising toolkit to achieve preferential performances that go beyond their disordered counterparts. Although current fabrication strategies via electric/magnetic force fields have made remarkable achievements, they necessitate special properties of nanosheets and suffer from an inferior orientation degree of nanosheets. Herein, a facile and universal approach is discovered to elaborate MXene-based nanocomposite hydrogels with highly oriented, heterogeneous architecture by virtue of supergravity to replace conventional force fields. The key to such architecture is to leverage bidirectional, force-tunable attributes of supergravity containing coupled orthogonal shear and centrifugal force field for steering high-efficient movement, pre-orientation, and stacking of MXene nanosheets in the bottom. Such a synergetic effect allows for yielding heterogeneous nanocomposite hydrogels with a high-orientation MXene-rich layer (orientation degree, f = 0.83) and a polymer-rich layer. The authors demonstrate that MXene-based nanocomposite hydrogels leverage their high-orientation, heterogeneous architecture to deliver an extraordinary electromagnetic interference shielding effectiveness of 55.2 dB at 12.4 GHz yet using a super-low MXene of 0.3 wt%, surpassing most hydrogels-based electromagnetic shielding materials. This versatile supergravity-steered strategy can be further extended to arbitrary nanosheets including MoS2, GO, and C3N4, offering a paradigm in the development of oriented nanocomposites.

Sandwich-Structured Mxene/Waste Polyurethane Foam Composites For Highly Efficient Electromagnetic Interference, Infrared Shielding and Joule Heating.

Electromagnetic interference (EMI) shielding and infrared (IR) stealth materials have attracted increasing attention owing to the rapid development of modern communication and military surveillance technologies. However, to realize excellent EMI shielding and IR stealth performance simultaneously remains a great challenge. Herein, a facile strategy is demonstrated to prepare high-efficiency EMI shielding and IR stealth materials of sandwich-structured MXene-based thin foam composites (M-W-M) via filtration and hot-pressing. In this composite, the conductive Ti3C2Tx MXene/cellulose nanofiber (MXene/CNF) film serves as the outer layer, which reflects electromagnetic waves and reduces the IR emissivity. Meanwhile, the middle layer is composed of a porous waste polyurethane foam (WPUF), which not only improves thermal insulation capacity but also extends electromagnetic wave propagation paths. Owing to the unique sandwich structure of "film-foam-film", the M-W-M composite exhibits a high EMI shielding effectiveness of 83.37 dB, and in the meantime extremely low emissivity (22.17%) in the wavelength range of 7-14 µm and thermal conductivity (0.19 W m-1 K-1), giving rise to impressive IR stealth performance at various surrounding temperatures. Remarkably, the M-W-M composite also shows excellent Joule heating properties, capable of maintaining the IR stealth function during Joule heating.

A Universal Biomacromolecule-Enabled Assembly Strategy for Constructing Multifunctional Aerogels with 90% Inorganic Mass Loading from Inert Nano-Building Blocks.

Inert inorganic nano-building blocks, such as carbon nanotubes (CNTs) and boron nitride (BN) nanosheets, possess excellent physicochemical properties. However, it remains challenging to build aerogels with these inert nanomaterials unless they are chemically modified or compounded with petrochemical polymers, which affects their intrinsic properties and is usually not environmentally friendly. Here, a universal biomacromolecule-enabled assembly strategy is proposed to construct aerogels with 90 wt% ultrahigh inorganic loading. The super-high inorganic content is beneficial for exploiting the inherent properties of inert nanomaterials in multifunctional applications. Taking chitosan-CNTs aerogel as a proof-of-concept demonstration, it delivers sensitive pressure response as a pressure sensor, an ultrahigh sunlight absorption (94.5%) raising temperature under light (from 25 to 71 °C within 1 min) for clean-up of crude oil spills, and superior electromagnetic interference shielding performance of up to 68.9 dB. This strategy paves the way for the multifunctional application of inert nanomaterials by constructing aerogels with ultrahigh inorganic loading.