Tunable Performance Research Articles

Self-Healing and Antifreezing/Antidrying Conductive Eutectohydrogel-Based Biosignal Monitoring Multisensors with Integrated Supercapacitor.

A novel self-healing and antifreezing/antidrying conductive eutectohydrogel, ideal for wearable multifunctional sensors and supercapacitors, is reported. Conductive eutectohydrogel with self-healing and facilely tunable mechanical performance is obtained by incorporation of trehalose and phytic acid as reversible cross-linkers into a polyacrylamide network, forming the dynamic hydrogen bonding and electrostatic interactions. Furthermore, combined use of deep eutectic solvent with water ensures the air stability as well as the antifreezing/antidrying characteristics. The synthesized eutectohydrogel exhibits a self-healing efficiency of 90.7% after 24 h at room temperature, Young's modulus of 140.9 kPa, and strain at break of 352.8%. With the eutectohydrogel as a versatile platform, self-healing strain and temperature sensors, electrocardiogram electrodes, and supercapacitor are fabricated, recovering the device performance after self-healing from complete bisection and exhibiting stable performance over a wide temperature range from -20 to 50°C. With a vertically integrated patch device of supercapacitor and strain sensor attached onto skin, various body movements are successfully detected using the energy stored in the supercapacitor, without performance degradation even after self-healing from complete bisection of the full patch device. This work demonstrates high potential application of the synthesized eutectohydrogel to flexible wearable devices featuring durability and longevity.

Platan seeds-derived PSC/Ni/Co composite with multi-morphologies as tunable microwave absorber

Biomass and its derived carbon materials, due to their glorious application value in the field of microwave absorption, have sparked a new round of research boom. Hereinto, platan seeds-derived carbon-based materials (PSC), offspring from direct carbonization of platan seeds, were ulteriorly processed and subjected to high-temperature carbonization treatment to synthesis PSC/Ni/Co composite with diversified morphology and tunable microwave absorption performance. The effect of nickel and cobalt ion concentrations on the absorption performance of composite materials was investigated in depth. The optimum reflection loss value (RLmin) of PSC/Ni can reach −47.36 dB, while its effective absorption broadband (EAB) is 5.8 GHz, ranging from 12–17.8 GHz, covering almost the whole Ku band. Compared with PSC/Ni composites, PSC/Co fulfils greater advantages in thickness and bandwidth. As for PSC/Ni/Co, the sample exhibits the optimal performance when Ni and Co ions are at equal concentrations, with an RLmin of −48.3 dB and an EAB of 5 GHz (13–18 GHz), which congealed the edges of both. Unequivocally, the morphological polymorphism of carbon-based-derived microwave absorbing materials with platan seeds as the carbon source is crucial to harvset lightweight, efficient and adjustable absorption properties, let alone its relatively simple and feasible preparation method. This may provide a new approach for engineering light-weight, cost effective and eco-friendly absorbing materials.

Wavelength Locking and Calibration of Fiber-Optic Ultrasonic Sensors Using Single-Sideband-Modulated Laser

Implementation of edge-filter detection for interrogating optical interferometric ultrasonic sensors is often hindered by the lack of cost-effective laser sources with agile wavelength tunability and good noise performance. The detected signal can also be affected by optical power variations and locking-point drift, negatively affecting the sensor accuracy. Here, we report the use of laser single-sideband generation with a dual-parallel Mach–Zehnder interferometer (DP-MZI) for laser wavelength tuning and locking in edge-filter detection of fiber-optic ultrasonic sensors. We also demonstrate real-time in situ calibration of the sensor response to ultrasound-induced wavelength shift tuning. The DP-MZI is employed to generate a known wavelength modulation of the laser, whose response is used to gauge the sensor response to the ultrasound-induced wavelength shifts in real time and in situ. Experiments were performed on a fiber-optic ultrasonic sensor based on a high-finesse Fabry–Perot interferometer formed by two fiber Bragg gratings. The results demonstrated the effectiveness of the laser locking against laser wavelength drift and temperature variations and the effectiveness of the calibration method against optical power variations and locking-point drift. These techniques can enhance the operational robustness and increase the measurement accuracy of optical ultrasonic sensors.

Design and Depolymerization of Bis(2‐hydroxyethyl) Terephthalate‐Containing Polyurethanes for Vat Photopolymerization

AbstractVat photopolymerization (VPP) of highly aromatic polyurethanes (PUs) expands the library of additive manufacturing (AM) materials and enables a vast array of ductile thermoplastics, rigid and flexible thermosets, and elastomers. Aromatic diisocyanates and various diols enable printing of rigid, highly aromatic cross‐linked parts, which offer high glass transition temperatures and tunable thermomechanical performance. The judicious control of molecular weight of the photo‐reactive telechelic oligomers allows for a fundamental study of the influence of cross‐link density in highly aromatic 3D PU printed objects. VPP AM produces objects with high resolution, smooth surface finish, and isotropic mechanical properties. Thermal post‐processing is critical in maintaining excellent thermomechanical properties with semi‐crystallinity as a function of cross‐link density. Due to the presence of two ester carbonyls in the bis(2‐hydroxyethyl) terephthalate chain extender, the printed parts are readily amenable to depolymerization with methanolysis to produce difunctional dimethyl dicarbamates under modest reaction conditions. Dimethyl dicarbamates serve as suitable monomers for subsequent polycondensation.

Theoretical Study of the Magnetic Mechanism of a Pca21 C4N3 Monolayer and the Regulation of Its Magnetism by Gas Adsorption.

For metal-free low-dimensional ferromagnetic materials, a hopeful candidate for next-generation spintronic devices, investigating their magnetic mechanisms and exploring effective ways to regulate their magnetic properties are crucial for advancing their applications. Our work systematically investigated the origin of magnetism of a graphitic carbon nitride (Pca21 C4N3) monolayer based on the analysis on the partial electronic density of states. The magnetic moment of the Pca21 C4N3 originates from the spin-split of the 2pz orbit from special carbon (C) atoms and 2p orbit from N atoms around the Fermi energy, which was caused by the lone pair electrons in nitrogen (N) atoms. Notably, the magnetic moment of the Pca21 C4N3 monolayer could be effectively adjusted by adsorbing nitric oxide (NO) or oxygen (O2) gas molecules. The single magnetic electron from the adsorbed NO pairs with the unpaired electron in the N atom from the substrate, forming a Nsub-Nad bond, which reduces the system's magnetic moment from 4.00 μB to 2.99 μB. Moreover, the NO adsorption decreases the both spin-down and spin-up bandgaps, causing an increase in photoelectrical response efficiency. As for the case of O2 physisorption, it greatly enhances the magnetic moment of the Pca21 C4N3 monolayer from 4.00 μB to 6.00 μB through ferromagnetic coupling. This method of gas adsorption for tuning magnetic moments is reversible, simple, and cost-effective. Our findings reveal the magnetic mechanism of Pca21 C4N3 and its tunable magnetic performance realized by chemisorbing or physisorbing magnetic gas molecules, providing crucial theoretical foundations for the development and utilization of low-dimensional magnetic materials.

Functional Carbon Springs Enabled Dynamic Tunable Microwave Absorption and Thermal Insulation.

Electromagnetic (EM) wave pollution and thermal damage pose serious hazards to delicate instruments. Functional aerogels offer a promising solution by mitigating EM interference and isolating heat. However, most of these materials struggle to balance thermal protection with microwave absorption (MA) efficiency due to a previously unidentified conflict between the optimizing strategies of the two properties. Herein, this study reports a solution involving the design of a carbon-based aerogel called functional carbon spring (FCS). Its unique long-range lamellar multi-arch microstructure enables tunable MA performance and excellent thermal insulation capability. Adjusting compression strain from 0% to 50%, the adjustable effective absorption bandwidth (EAB) spans up to 13.4GHz, covering 84% of the measured frequency spectrum. Notably, at 75% strain, the EAB drops to 0GHz, demonstrating a novel "on-off" switchability for MA performance. Its ultralow vertical thermal conductivity (12.7mW m-1 K-1) and unique anisotropic heat transfer mechanism endow FCS with superior thermal protection effectiveness. Numerical simulations demonstrate that FCS outperforms common honeycomb structures and isotropic porous aerogels in thermal management. Furthermore, an "electromagnetic-thermal" dual-protection material database is established, which intuitively demonstrates the superiority of the solution. This work contributes to the advancement of multifunctional MA materials with significant potential for practical applications.

Exploring grain size and composition effects on the functional properties of BaGexTi1-xO3 ceramics

This study investigates BaGexTi1-xO3 ceramics with varying compositions (x = 0.010, 0.018, 0.100) produced by solid-state reaction, exploring the impact of composition and sintering temperatures (1150 °C, 1200 °C, 1300 °C) on functional characteristics (low-field dielectric, tunability, ferroelectric switching). Increasing Ge amount and sintering temperatures enhances sinterability of BaGexTi1-xO3 to almost complete densification. Room temperature permittivity ranges from 1000 to 2000, with dielectric losses below 10%. For small Ge additions, the dielectric behavior and phase transitions mirror BaTiO3 ceramics. Increasing Ge addition results in a slight increase of the Curie temperature. Dielectric relaxation mechanisms involve two activation energy ranges related to oxygen vacancies and ionic conduction. Ceramics with larger grain sizes exhibit well-defined ferroelectric P(E) loops, while fine-grained ones contain extrinsic contributions. The highest tunability performances are found for the lowest Ge additions, sintered at 1150 °C, which are able to withstand the application of the highest dc field.

Effect of crystalline TiO2 on V2O5WO3/TiO2 as tunable low-temperature shift De-NOx catalyst

Based on the crystalline size of anatase TiO2, a series of tunable low-temperature shift V2O5-WO3/TiO2 (VW/Ti) catalysts for NH3 selective catalytic reduction (NH3-SCR) of NOx were prepared by impregnation process. These catalysts contained a loading amount of 2 wt% WO3 and either 2 or 5 wt% V2O5. The tunable low-temperature shift De-NOx performance of the VW/Ti catalysts was significantly enhanced and dramatically decreased after heat treatment of TiO2 from 100 °C to 700 °C (Ti100–Ti700). Nearly 100 % De-NOx efficiency was achieved at a gas hourly space velocity (GHSV) of 60,000 h−1. A notable shift from higher to lower temperatures was observed from V2W2/Ti100 to V2W2/Ti600; however, the activity was lost for V2W2/Ti650 to V2W2/Ti700. When the V2O5 loading increased from 2 wt% to 5 wt%, the V5W2/Ti600 showed the highest De-NOx efficiency at 225 °C, demonstrating a remarkable synergistic effect compared to the V2W2/Ti100 catalyst, which achieved maximum efficiency at 375 °C. The De-NOx performance and low-temperature shift effect of these catalysts were elucidated by considering TiO2 crystalline size, the synergistic effect between V2O5 content and TiO2, and the V4+/V5+ oxidation state of V2O5 in the catalyst. Additionally, the high crystalline TiO2-based V2W2/Ti600 catalyst prepared in this study is expected to effectively decompose NOx at low temperatures, in contrast to the low crystalline TiO2-based V2W2/Ti100 catalyst.

CO2-based polyurethane elastomers with enhanced mechanical and tunable room-temperature damping performances

Elastomers provide excellent damping performance owing to their unique viscoelasticity, which are widely used as vibration and noise reduction materials. However, conventional rubber-based elastomers with a low glass transition temperature (Tg) and narrow damping range are difficult to adapt to room-temperature conditions. Additionally, most of petroleum-based elastomers hinder the sustainable development. In this work, a series of novel polyurethane elastomers was synthesized using carbon-fixed CO2-based polycarbonate propylene diol (PPCD). The impact of hard segment (HS) content on the thermal, mechanical, and damping properties of CO2-based polyurethane (PU) was comprehensively investigated. Increasing the HS content from 16 % to 44 % increased the Tg from −3.8 °C to 21.7 °C, covering the entire damping range at room temperature with an adjustable damping performance. Furthermore, the tensile strength increased from 7.2 MPa to 27.0 MPa. The synthesis of CO2-based PU can propel the utilization of PU in damping applications, enabling sustainable advancement of the PU industry.

Synthesis of hydrothermal carbonation carbon with tunable photocatalytic performance for trimethoprim degradation using an ethanol-water co-solvent strategy: Influence of ethanol concentration

Hydrothermal carbonation carbon (HTCC) is increasingly acknowledged as a promising photocatalytic material for degrading antibiotics in water due to its green and cost-effective properties. While ethanol and water are prevalent solvents in the preparation of HTCC, research examining the influence of solvent combinations on the photocatalytic efficacy of HTCC is lacking. The influence of various ethanol-water co-solvent preparation ratios (0, 20, 40, 60, 80, and 100 wt% ethanol concentration in the co-solvent) on the photocatalytic degradation activity of trimethoprim (TMP) by HTCC was examined in this study. The results indicated that altering ethanol solvent preparation concentrations modulates the morphological characteristics, surface functional groups, and photochemical attributes of co-solvent HTCC materials. HTCC prepared using an 80 wt% ethanol solvent concentration demonstrated the most efficient TMP photocatalytic degradation (>90%). The TMP degradation kinetic constants of 80 wt% ethanol concentration co-solvent HTCC were 3.29 and 1.51 times greater compared to those of HTCC prepared using only water or ethanol as solvents, respectively. •O2− predominantly served as the key reactive oxygen species in TMP photocatalytic decomposition by 80 wt% ethanol concentration co-solvent HTCC, with its generation mechanism linked to the intrinsic furan donor-acceptor (D-A) conjugated structure of HTCC. An increase in ethanol solvent preparation concentration promotes the formation of more furan units, increased coupling of donor-acceptor (D-A) conjugation, a lower D-A ratio, and enhanced generation of short-chain aliphatics in HTCC, which then directly impacts its electron transfer capability, bandgap structure, light absorption capacity, and photocatalytic degradation efficiency. This work provides fresh strategies for the preparation and photocatalytic performance modulation of water treatment photocatalysts based on HTCC.

Mechanical and shape-memory properties of TPMS with hybrid configurations and materials

ABSTRACT Triply periodic minimal surface (TPMS) structures with excellent properties of stable energy absorption, light weight, and high specific strength could potentially spark immense interest for novel and programmable functions by combining smart materials, e.g. shape memory polymers (SMPs). This work proposes TPMS lattices with hybrid configurations and materials that are composed of viscoelastic and shape-memory materials with the aim to bring temperature-dependent mechanical properties and additional dissipation mechanisms. Different configurations and diverse materials of polylactic acid (PLA), fiber-reinforced PLA, and polydimethylsiloxane (PDMS) are induced, generating five types of TPMS lattices, including (Schoen’s I-WP) IWP uniform lattice, IWP lattice with density gradient, hybrid configurations, hybrid materials, and filled PDMS, which are fabricated by 3D printing. The fracture morphologies and the distribution of carbon fibers are demonstrated via scanning electron microscopy with a focus on the influence of carbon fiber on shape-memory and mechanical properties. Shape recovery tests are conducted, which proves good shape memory properties and reusable capability of TPMS lattice. The combined methods of experiments and numerical simulation are adopted to evaluate mechanical properties, which presents multi-stage energy absorption ability and tunable vibration isolation performances associated with temperature and hybridization designs. This work can promote extensive research and provide substantial opportunities for TPMS lattices in the development of functional applications.

Nanoenergetic Materials: From Materials to Applications.

Both nanoscience and nanotechnology have undoubtedly contributed significantly to the development of thermite-based nanoenergetic materials (NEMs) with tunable and tailorable combustion performance and their subsequent integration into devices. Specifically, this review article reflects the immense paybacks in designing and fabricating ordered/disordered assembly of energetic materials over multiple length scales (from nano- to milli-scales) in terms of realization of desired reaction rates and sensitivity. Besides presenting a critical review of present advancements made in the synthesis of NEMs, this article touches upon aspects related to various applications concomitantly. The article concludes with the author's summary of the insurmountable challenges and the road ahead toward the deployment of nanoenergetic materials in practical applications. The real challenge lies in the ability to preserve the self-assembly of fuel and oxidizer nanoparticles achieved at the nanoscale while synthesizing macroscale energetic formulations using advanced fabrication techniques both in bulk and thin film forms. Most importantly, these self-assembled NEMs have to exhibit excellent combustion performance at reduced sensitivity to external stimuli such as electrostatic discharge (ESD), friction and impact.

Insights into solid-contact ion-selective electrodes based on laser-induced graphene: Key performance parameters for long-term and continuous measurements.

This work aims to serve as a comprehensive guide to properly characterize solid-contact ion-selective electrodes (SC-ISEs) for long-term use as they advance toward calibration-free sensors. The lack of well-defined SC-ISE performance criteria limits the ability to compare results and track progress in the field. Laser-induced graphene (LIG) is a rapid and scalable method that, by adjusting the CO2 laser parameters, can create LIG substrates with tunable surface properties, including wettability, surface chemistry, and morphology. Herein, we fabricate laser-induced graphene (LIG) solid-contact electrodes using different laser settings and subsequently convert them into ion-selective sensors using a potassium-selective membrane. We measure the aforementioned tunable surface properties and correlate them with resultant low-frequency capacitance and water layer formation in an effort to pinpoint their effects on the sensitivity (Nernstian response), reproducibility (E°' variation), and potential stability of the LIG-based SC-ISEs. More specifically, we demonstrate that the surface wettability of the LIG substrate, which can be tuned by controlling the lasing parameters, can be modified to exhibit hydrophobic (contact angle > 90°) and even highly hydrophobic surfaces (contact angle ≈ 130°) to help reduce sensor drift. Recommendations are also provided to ensure proper and robust characterization of SC-ISEs for long-term and continuous measurements. Ultimately, we believe that a comprehensive understanding of the correlation between LIG tunable surface properties and SC-ISE performance can be used to improve the electrochemical behavior and stability of SC-ISEs designed with a wide range of materials beyond LIG.

Synthesis of MnFe-C core–shell nanoparticles with tunable microwave absorption performance by designing the Mn/Fe ratio

Metal-C nanoparticles with MnFe nanocores and their microwave absorption performances with design Mn/Fe ratios have been rarely reported in previous studies. In this work, MnFe-C core–shell nanoparticles with tunable Mn/Fe ratios were prepared by a one-step metal organic chemical vapor deposition method. It was found that the magnetic properties and microwave absorption performances of the nanoparticles could be well tunable by designing Mn/Fe ratios in their nanocores. These results suggest that the as-synthesized MnFe-C core–shell nanoparticles have great potential for microwave absorption applications.

Multifunctional carbon Fiber@TiO2/C aerogels derived from MXene for pressure tunable microwave absorption

Developing microwave absorption (MA) materials with dynamically tunable performance stands as a pivotal endeavor to fulfill the escalating demands of electronic devices and military equipment in complex electromagnetic environments. This study presents advanced hierarchical CF@TiO2/C aerogels with pressure tunable MA performance, engineered through a novel in-situ oxidation process of MXene on carbon fiber (CF) substrates. This process facilitates the formation of a two-dimensional (2D) TiO2/C hybrid layer, which significantly enhances the polarization loss capabilities of the aerogels while maintaining excellent mechanical resilience. The unique architecture of these aerogels facilitates the modulation of their electrical conductivity and permittivity via pressure, thus enabling dynamically adjustable MA performance. Upon compression (50 %), the CF@TiO2/C aerogels showcase an outstanding effective absorption bandwidth (EAB) of 7.84 GHz, accompanied by a remarkable minimum reflection loss (RLmin) of −74.38 dB. Notably, the EAB of CF@TiO2/C aerogels can be precisely tuned from 4 to 18 GHz (covering the C-band, X-band, and Ku-band), with maximum changes in RLmin values (ΔRLmin) reaching as high as 59.30 dB, indicating substantial tunability under varying pressure. Moreover, the CF@TiO2/C aerogels also demonstrate outstanding thermal insulation and pressure sensing performance, highlighting their potential for multifunctional applications. This research not only sheds light on the intricate interplay between nanostructured materials and electromagnetic waves interactions but also sets a new strategy for the design of multifunctional, tunable microwave absorbers suitable for complex electromagnetic environments in modern electronic and military applications.

Versatile and Tunable Performance of PVA/PAM Tridimensional Hydrogel Models for Tissues and Organs: Augmenting Realism in Advanced Surgical Training.

The increasing complexity and difficulty of surgical procedures have led to a rise in medical errors within clinical settings in recent years. Gastrointestinal diseases, in particular, present significant medical challenges and impose substantial economic burdens, underscoring the urgent need for experiential, high-fidelity gastrointestinal surgical training tools. This study leverages patient-specific computed tomography (CT) and magnetic resonance imaging (MRI) data, combined with 3D printed manufacturing, to develop hydrogel organ models with tunable performance and tissue-mimicking softness. These properties are achieved by regulating the freeze-thaw cycles, cross-linking agents, and the concentration of incorporated antibacterial nanoparticles in DN hydrogels. Through the application of indirect 3D printing and the "sacrificial material method", we successfully fabricate organ tissues such as the stomach, intestines, and blood vessels with high precision. In ex vivo surgical training demonstrations, these tissue-like soft hydrogels provide an effective platform for preoperative simulation and surgical training in digestive surgery, accommodating various surgical procedures and accurately simulating intraoperative bleeding. The development of advanced bionic organ models with specific and tunable characteristics based on DN hydrogels is poised to significantly advance surgical training, medical device testing, and the reform of medical education.

Continuously tunable ultrasonic focusing by Moiré metalenses

Tunable ultrasonic focusing holds great significance in both medicine and engineering. Recent advancements in metalenses have introduced approaches for tunable acoustic focusing, but their complex configurations and limited tuning range remain challenges. Here, acoustic Moiré metalenses (AMMs) are proposed to achieve continuously tunable ultrasonic focusing in water. Two cascading metasurfaces that can function as Moiré diffractive elements make up the AMM. By mutually rotating the metasurface, the focal point of the AMM can be continuously tuned in a large range. The focal length can be adjusted continuously from ∼14.3λ0to ∼50λ0for the axial focusing. We further show that the well-designed AMM can achieve the continuously tunable lateral focusing, with the deflection angle of the focal point being tunable between approximately -40°,40°. Both simulation and experimental results confirm the excellent tunable focusing performances of the AMMs. The proposed AMMs with continuously tunable focusing capability may have potential applications in ultrasonic imaging and ultrasound treatment.

MXene-based kirigami designs: showcasing reconfigurable frequency selectivity in microwave regime

Today’s wireless environments, soft robotics, and space applications demand delicate design of devices with tunable performances and simple fabrication processes. Here we show strain-based adjustability of RF/microwave performance by applying frequency-selective patterns of conductive Ti3C2Tx MXene coatings on low-cost acetate substrates under ambient conditions. The tailored performances were achieved by applying frequency-selective patterns of thin Ti3C2Tx MXene coatings with high electrical conductivity as a replacement to metal on low-cost flexible acetate substrates under ambient conditions. Under quasi-axial stress, the Kirigami design enables displacements of individual resonant cells, changing the overall electromagnetic performance of a surface (i.e., array) within a simulated wireless channel. Two flexible Kirigami-inspired prototypes were implemented and tested within the S, C, and X (2-4 GHz, 4-8 GHz, and 8-12 GHz) microwave frequency bands. The resonant surface, having ~1/4 of the size of a standard A4 paper, was able to steer a beam of scattered waves from each resonator by ~25°. Under a strain of 22%, the resonant frequency of the wired co-planar resonator was shifted by 400 MHz, while the reflection coefficient changed by 158%. Deforming the geometry impacted the spectral response of the components across three arbitrary frequencies in the 4-10 GHz frequency range. With this proof of concept, we anticipate implementing thin films of MXenes on technologically relevant substrates, achieving multi-functionality through cost-effective and straightforward manufacturing.

Cellulose nanofiber powered interface engineering strategy to manufacture mechanically stable, moldable, recyclable, and biodegradable cellulose foam

In this work, an ingenious and energy-efficient interface engineering strategy is developed to manufacture pulp cellulose foam via incorporating cellulose nanofiber/alkyl ketene dimer (CNF/AKD) Pickering emulsions. In this strategy, CNF/AKD emulsion can uniformly anchor onto pulp microfiber surface, not only achieving interfacial exoskeleton reinforcement, but also enabling low energy surface, which facilitates the direct and large-scale production of lightweight pulp/CNF/AKD (PCA) foam by oven drying without requiring any harmful crosslinking chemistries. By simply regulating the mass fractions of CNF and AKD in emulsion, the prepared PCA foams can achieve excellent and tunable 3D porous structure, mechanical performance, water resistance and wet stability. The dry compressive modulus and wet compressive modulus underwater of PCA foams with low density of 0.09 g/cm3 can reach 0.67 and 0.57 MPa, respectively. Even 1 week in water, the compressive modulus still retains 76.2 % of initial modulus. Notably, the proposed interface engineering strategy provides remarkable formability, moldability and structural designability, enabling cellulose foam to be customized into complex and delicate 3D macroscopic structures for different scenarios. Furthermore, the PCA foam displays economically feasible closed-loop recyclability by easy hot-water disintegration and natural biodegradability in soil. Therefore, this work proves a cost-effective and viable interface engineering strategy for scalable production of lightweight, mechanically stable, recyclable, biodegradable cellulose foams with high environmental benefits and low petrochemical consumption.

Lightweight and compressible PANI/Ti3C2Tx/EVA composite foam for tunable microwave absorption

Dynamic deformation and absorbing regulation are still challenging for designing lightweight and high-efficiency microwave absorbing materials, which are of great indispensability to satisfy changeable and complex electromagnetic environments. Herein, a compressible composite foam with sea-island structure was prepared by loading porous polyaniline (PANI)/Ti3C2Tx composites on ethylene/vinyl acetate (EVA) skeleton via a thermally induced phase separation strategy. The composite foam exhibits a minimum reflection loss (RLmin) of −57.84 dB and an effective absorption bandwidth (EAB, RL ≤ −10 dB) of 1.86 GHz (8.2–10.05 GHz) at 3.4 mm. Notably, the microwave absorption (MA) performance can be precisely regulated by simply adjusting the compression ratio of composite foam. The RL peaks shift towards higher frequencies with increasing compression ratios, originating from changes in the internal conductive network. Even under 30 % compression strain, the composite foam still maintains RLmin of −21.53 dB and broadens EAB up to 2.71 GHz at 2.0 mm. This combination of compression capabilities and dynamically tunable MA performance may expand a novel approach to designing multifunctional polymer-based foam.