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Tactile sensors play a key role in human-machine interfaces (HMIs) for augmented and virtual reality, point-of-care devices, and human-robot collaboration, which show the promise of revolutionizing our ways of life. Here, we present a sensor (EMTS) that utilizes the magnetoelastic effect in a soft metamaterial to convert mechanical pressure into electrical signals. With this unique mechanism, the proposed EMTS simultaneously possesses self-powering, waterproof, and compliant features. The soft metamaterial is essentially a porous magnetoelastomer structure designed based on the Fourier series expansion, which allows for programmable mechanical response and sensing performance of the EMTS. Fabricated by simple 3D-printed molds, the EMTS also holds potential for low-cost production. Particularly, the porous magnetoelastomer structure comes with selectable buckling instabilities that can significantly enhance biomechanical-to-electrical energy conversion. Also, with the embedded magnetic microparticles, the energy-absorbing performance of the sensor is greatly improved, which is highly beneficial to HMIs. To pursue practical applications, the EMTSs are further integrated with two systems as control and perception modules. It is demonstrated that the EMTS is able to identify different hand gestures to control a lighting system even in a high-humidity environment. Also, the EMTS stands out for its superior capability of simultaneous impact perception and energy absorption in drop tests. Overall, with its compelling array of features, the presented EMTS gives impetus to multi-sensing technology and practically enables a variety of HMI applications.

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High-efficiency photon color conversion is an approach of great potential for implementing color display. Inspired by the observation of emission enhancement in a nanoscale cavity, a novel technique to fabricate an array of color converter by mixing colloidal quantum dots (QDs) with the electrolyte of an electrochemical etching (ECE) process is demonstrated. In this process, QDs flow with the electrolyte into the etched subsurface nanoscale porous structure (PS) and settle inside. Since the PS formation and hence QD insertion are controlled by the flow path of the applied electric current in the ECE process, this technique can be used for fabricating any graphic pattern. The nanostructure of such a QD-inserted mesa is examined to confirm QD insertion. Although only single-color mesa arrays are demonstrated in this paper, this technique can be used for fabricating a multiple-color mesa array if a QD or a light-emitting nanoparticle of higher thermal stability is available.

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A three-dimensional (3D) hierarchical microfiber bundle-based scaffold integrated with silver nanowires (AgNWs) and porous polyurethane (PU) was designed for the Joule heater via a facile dip-coating method. The interconnected micrometer-sized voids and unique hierarchical structure benefit uniform AgNWs anchored and the formation of a high-efficiency 3D conductive network. As expected, this composite exhibits a superior electrical conductivity of 1586.4 S/m and the best electrothermal conversion performance of 118.6 °C at 2.0 V compared to reported wearable Joule heaters to date. Moreover, the durable microfiber bundle-PU network provides strong mechanical properties, allowing for the stable and durable electrothermal performance of such a composite to resist twisting, bending, abrasion, and washing. Application studies show that this kind of Joule heater is suitable for a wide range of applications, such as seat heating, a heating jacket, personal thermal management, etc.

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In this study, a novel bionic periosteum (BP)-bioactive glass fiber membrane (BGFM) is designed. The introduction of magnesium ion (Mg2+) and zinc ion (Zn2+) change the phase separation during the electrospinning (ES) jet stretching process. The fiber's pore structure transitions from connected to closed pores, resulting in a decrease in the rapid release of metal ions while also improving degradation via reducing filling quality. Additionally, the introduction of magnesium (Mg) and zinc (Zn) lead to the formation of negative charged tetrahedral units (MgO4 2- and ZnO4 2-) in the glass network. These units effectively trap positive charged metal ions, further inhibiting ion release. In vitro experiments reveal that the deigned bionic periosteum regulates the polarization of macrophages toward M2 type, thereby establishing a conducive immune environment for osteogenic differentiation. Bioinformatics analysis indicate that BP enhanced bone repair via the JAK-STAT signaling pathway. The slow release of metal ions from the bionic periosteum can directly enhance osteogenic differentiation and vascularization, thereby accelerating bone regeneration. Finally, the bionic periosteum exhibits remarkable capabilities in angiogenesis and osteogenesis, demonstrating its potential for bone repair in a rat calvarial defect model.

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Developing biochar with large specific surface area (SSA), heteroatom doping, and porous structure is attracting substantial attention to absorb electromagnetic wave (EMW) in recent. Herein, a novel method of ethanol and KOH co-treatment is used to produce the biomass carbon deriving from pitaya peels. The obtained carbon possesses the high SSA of 1580 m2/g, successful N/O atoms co-doping, and massive pores with different size. The results of EMW absorption measurement show that the prepared biochar could achieve over 99% absorpition to EMW, which the highest reflection loss is of ca. -45.25 dB at 7.54 GHz with an effective absorption bandwidth (EAB) of ca. 4.87 GHz. The execellent microwave absorption property is caused by the surface defects, dipole and interface polarizations of the synthesized biochar owning unique microstructure and N/O atoms co-doping. Hence, this avenue provides a new reference for fabricating low-cost and eco-friendly biochar as a microwave absorber.

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High-performance compact capacitive energy storage is vital for many modern application fields, including grid power buffers, electric vehicles, and portable electronics. However, achieving exceptional volumetric performance in supercapacitors is still challenging and requires effective fabrication of electrode films with high ion-accessible surface area and fast ion diffusion capability while simultaneously maintaining high density. Herein, a facile, efficient, and scalable method is developed for the fabrication of dense, porous, and disordered graphene through spark-induced disorderly opening of graphene stacks combined with mechanical compression. The obtained disordered graphene achieves a high density of 1.18 g cm-3, sixfold enhanced ion conductivity compared to common laminar graphene, and an ultrahigh volumetric capacitance of 297 F cm-3 in ionic liquid electrolyte. The fabricated stack cells deliver a volumetric energy density of 94.2 Wh L-1 and a power density of 13.7 kW L-1, representing a critical breakthrough in capacitive energy storage. Moreover, the proposed disordered graphene electrodes are assembled into ionogel-based all-solid-state pouch cells with high mechanical stability and multiple optional outputs, demonstrating great potential for flexible energy storage in practical applications.

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Nanoporous metals, fabricated via dealloying, offer versatile applications but are typically limited to unimodal porous structures, which hinders the integration of conflicting pore-size-dependent properties. A strategy is presented that exploits the homologous temperature (TH)-dependent scaling of feature sizes to generate hierarchical porous structures through multistep dealloying at varied TH levels, adjusted by altering dealloying temperatures or the material melting points. This technique facilitates the creation of monolithic architectures of bimodal porous nickel and trimodal porous carbon, each characterized by well-defined, self-similar bicontinuous porosities across distinct length scales. These materials merge extensive surface area with efficient mass transport, showing improved current delivery and rate capabilities as electrodes in electrocatalytic hydrogen production and electrochemical supercapacitors. These results highlight TH as a unifying parameter for precisely tailoring feature sizes of dealloyed nanoporous materials, opening avenues for developing materials with hierarchical structures that enable novel functionalities.

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Iron sulfides with high theoretical capacity confront the challenges of low rate capability and severe capacity fading for sodium storage, which are mainly caused by poor electron/ion transport kinetics and drastic volume fluctuations during cycling. Herein, to mitigate these obstacles, a multi-step synthetic tactic involving solvothermal, carbonization, and subsequent sulfurization is put forward for the construction of wire-like structure by confining Fe7S8 particles in porous N-doped carbon framework (denoted as Fe7S8/PNC) using zinc iron nitrilotriacetate as template. By partially substituting Fe3+ with Zn2+ in the metal coordination complex, the porous structure of coordination complex derived carbon framework can be regulated through pore structure engineering of Zn nanodroplets. The desired porous and robust core/shell structure can not only afford favorable electron/Na+ transport paths and additional active sites for Na+ storage, but also provide reinforced structural integrity of interior Fe7S8 particles by retarding the pulverization and buffering the mechanical stress against volume fluctuations. As anode for sodium-ion batteries, the optimal Fe7S8/PNC delivers a high reversible capacity (743 mAh g-1 at 0.1 A g-1), superior rate capability (553 mAh g-1 at 10 A g-1), and long-term cycling stability (602 mAh g-1 at 5 A g-1 with 98.5% retention after 1000 cycles).

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Two-dimensional (2D) materials with excellent properties and widespread applications have been explosively investigated. However, their conventional synthetic methods exhibit concerns of limited scalability, complex purification process, and incompetence of prohibiting their restacking. The blowing strategy, characterized by gas-template, low-cost, and high-efficiency, presents a valuable avenue for the synthesis of 2D-based foam materials and thereby addresses these constraints. Whereas, its comprehensive introduction has been rarely outlined so far. This review commences with a synopsis of the blowing strategy, elucidating its development history, the statics and kinetics of the blowing process, and the choice of precursor and foaming agents. Thereafter, we dwell at length on across-the-board foams enabled by the blowing route, like BxCyNz foams, carbon foams, and diverse composite foams consisting of carbon and metal compounds. Following that, a wide-ranging evaluation of the functionality of the foam products in fields such as energy storage, electrocatalysis, adsorption, etc. is discussed, revealing their distinctive strength originated from the foam structure. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future research priorities in this rapidly developing method.

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Promotion of oxygen reduction reaction (ORR) kinetics, to a large extent, depends on the rational modulation of the electronic structure and mass diffusion of electrocatalysts. Herein, a ferrocene (Fc)-assisted strategy is developed to prepare Fc-trapped ZnMo-hybrid zeolitic imidazolate framework (Fc@ZnMo-HZIF-50) and the derived Fe single atom coupling with MoC nanoparticles, coembedded in hierarchically porous N-doped carbon cubes (MoC@FeNC-50). The introduced Fc is utilized not only as an iron source for single atoms but also as a morphology regulator for generating a hierarchically porous structure. The redistribution of electrons between Fe single atoms and MoC nanoparticles effectively promotes the adsorption of O2 and the formation of *OOH intermediates during the ORR process. Along with a 3D hierarchically porous architecture for enhanced mass transport, the as-fabricated MoC@FeNC-50 presents excellent activity (E1/2 = 0.83 V) and durability (only 9.5% decay in current after 40000 s). This work could inspire valuable insights into the construction of efficient electrocatalysts through electron configuration and kinetics engineering.

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Compared to lithium (Li) anode, the alloy/Li-alloy anodes show more compatible with sulfide solid electrolytes (SSEs), and are promising candidates for practical SSE-based all-solid-state Li batteries (ASSLBs). In this work, a porous Li-Al alloy (LiAl-p) anode is crafted using a straightforward mechanical pressing method. Various characterizations confirm the porous nature of such anode, as well as rich oxygen species on its surface. To the best knowledge, such LiAl-p anode demonstrates the best room temperature cell performance in comparison with reported Li and alloy/Li-alloy anodes in SSE-based ASSLBs. For example, the LiAl-p symmetric cells deliver a record critical current density of 6.0 mA cm-2 and an ultralong cycling of 5000 h; the LiAl-p|LiNi0.8Co0.1Mn0.1O2 full cells achieve a high areal capacity of 11.9 mAh cm-2 and excellent durability of 1800 cycles. Further in situ and ex situ experiments reveal that the porous structure can accommodate volume changes of LiAl-p and ensure its integrity during cycling; and moreover, a robust Li inorganics-rich solid electrolyte interphase can be formed originated from the reaction between SSE and surface oxygen species of LiAl-p. This study offers inspiration for designing high-performance alloy anodes by focusing on designing special architecture to alleviate volume change and constructing stable interphase.

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Metal thiophosphites have recently emerged as a hot electrode material system for sodium-ion batteries because of their large theoretical capacity. Nevertheless, the sluggish electrochemical reaction kinetics and drastic volume expansion induced by the low conductivity and inherent conversion-alloying reaction mechanism, require urgent resolution. Herein, a distinctive porous core-shell structure, denoted as SnPS3@C, is controllably synthesized by synchronously phosphor-sulfurizing resorcinol-formaldehyde-coated tin metal-organic framework cubes. Thanks to the 3D porous structure, the ion diffusion kinetics are accelerated. In addition, SnPS3@C features a tough protective carbon layer, which improves the electrochemical activity and reduces the polarization. As expected, the as-prepared SnPS3@C electrode exhibits superior electrochemical performance compared to pure SnPS3, including excellent rate capability (1342.4 and 731.1 mAh g-1 at 0.1 and 4 A g-1, respectively), and impressive long-term cycling stability (97.9% capacity retention after 1000 cycles at 1 A g-1). Moreover, the sodium storage mechanism is thoroughly studied by in-situ and ex-situ characterizations. This work offers an innovative approach to enhance the energy storage performance of metal thiophosphite materials through meticulous structural design, including the introduction of porous characteristics and core-shell structures.

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Passive daytime radiative cooling (PDRC) emerges as a promising cooling strategy with an attractive feature of no energy and refrigerant consumption. In the current study, for the purpose of achieving cost-efficient fabrication of a PDRC polymeric material, a microporous polymeric coating is prepared by a novel "inverse emulsion"-"breath figure" (Ie-BF) method using water droplets as pore-formation template, and the porous morphologies of both the surface and bulk layer can be dynamically manipulated by tuning the emulsion composition as well as environmental conditions. Therefore, the solar reflectivity of the Ie-BF coating can be efficiently tuned within a rather wide range (21-91%) by facile modulation of porosity and thickness. The Ie-BF coating with a thickness of only 125 µm exhibits a high solar reflectance of 85.4% and a long-wave infrared emissivity of 96.3%, realizing a subambient radiative cooling of 6.7 °C and a cooling power of ∼76 W m-2 in the open air. Moreover, by employing the reversible feature of in situ pore formation and erasure combined with the additional attachment of a carbon black layer, the composite film could be easily switched between cooling and heating modes by solvent post-treatment. This research establishes a cost-efficient strategy with high flexibility in the structural manipulation concerning the construction of porous polymeric PDRC coating.

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Solar energy, as a clean and renewable energy source, holds significant promise for addressing water shortages. Utilizing solar energy for water evaporation is seen as an effective solution in this regard. While many existing interfacial photothermal water evaporation systems rely on nanoparticles or graphene as photothermal or support materials, this study introduced polydopamine (PDA) as a photothermal material due to its environmental friendliness and excellent photon absorption characteristics that closely match the solar spectrum. Polystyrene (PS) was also introduced as a support material for its porous structure and density similar to water, enabling it to float on water. The resulting PS-PDA composite porous structure solar evaporator exhibited a photothermal conversion efficiency comparable to nanoparticles (over 75%), yet with lower production costs and minimal environmental impact. This innovative approach offers a scalable solution for water-scarce regions, providing a cost-effective and efficient means to address water scarcity. The use of PDA and PS in this context highlights the potential for utilizing common materials in novel ways to meet pressing environmental challenges.

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Polybenzoxazine (PBz) aerogels hold immense potential, but their conventional production methods raise environmental and safety concerns. This research addresses this gap by proposing an eco-friendly approach for synthesizing high-performance carbon derived from polybenzoxazine. The key innovation lies in using eugenol, ethylene diamine, and formaldehyde to create a polybenzoxazine precursor. This eliminates hazardous solvents by employing the safer dimethyl sulfoxide. An acidic catalyst plays a crucial role, not only in influencing the microstructure but also in strengthening the material's backbone by promoting inter-chain connections. Notably, this method allows for ambient pressure drying, further enhancing its sustainability. The polybenzoxazine acts as a precursor to produce two different carbon materials. The carbon material produced from the calcination of PBz is denoted as PBZC, and the carbon material produced from the gelation and calcination of PBz is denoted as PBZGC. The structural characterization of these carbon materials was analyzed through different techniques, such as XRD, Raman, XPS, and BET analyses. BET analysis showed increased surface of 843 m2 g-1 for the carbon derived from the gelation method (PBZGC). The electrochemical studies of PBZC and PBZGC imply that a well-defined morphology, along with suitable porosity, paves the way for increased conductivity of the materials when used as electrodes for supercapacitors. This research paves the way for utilizing heteroatom-doped, polybenzoxazine aerogel-derived carbon as a sustainable and high-performing alternative to traditional carbon materials in energy storage devices.

RESUMEN

Solar-powered interfacial evaporation is a developing and sustainable technique increasingly utilized in desalination and wastewater purification. This technology involves the creation of cellulose nanofiber (CNF)/polylactic acid (PLA) composite aerogels through the Pickering emulsion approach. Self-floating aero-hydrogel (E-VGP) with a hierarchical porous structure was formed on a viscous mixture containing polyvinyl alcohol (PVA), peach gum polysaccharide (PGP), and polypyrrole (PPy) via an in-situ polymerization process. Furthermore, by modifying the hydrolysis time of PGP with a hyperbranched polyhydroxy structure, VGP hybrid hydrogels of varying microscopic molecular sizes were produced. Additionally, solar vapor generators (SVG) with diverse macroscopic structures were fabricated using molds. The V8G4-12hP0.2 hybrid hydrogel, synthesized using PGP hydrolyzed for 12 h, exhibited an evaporation enthalpy of water at 1204 J g-1. This capacity effectively activates water and enables low enthalpy evaporation. Conversely, the macrostructural design allows the cylindrical rod raised sundial-shaped structure of SVG3 to possess an expanded evaporation area, minimize energy loss, and even harness additional energy from its nonradiative side. Consequently, this micro-macrostructural design enables SVG3 to attain an exceptionally high evaporation rate of 3.13 kg m-2 h-1 under 1 Sun exposure. Moreover, SVG3 demonstrates robust water purification abilities, suggesting significant potential for application in both desalination and industrial wastewater treatment.

Asunto(s)

RESUMEN

The aim of this work was the characterization of polymer microspheres obtained by the suspension polymerization of divinylbenzene (DVB) and glycidyl methacrylate (GMA), depending on the pore-forming diluents and molar ratio of monomers. The assessed properties included the chemical and porous structure, thermal stability, and sorption capacity of the obtained polymers towards methylene blue. The abovementioned characteristic was carried out for two series of copolymers with molar ratios of monomers of 1:2, 1:1 and 2:1, synthetized with toluene and a mixture of decanol and benzyl alcohol. The structure of the polymers was confirmed by FTIR and elemental analysis. The results of TGA demonstrated the main influence on thermal stability was the composition of polymers, whereas the impact of porogens was negligible. The SBET varied in the range of 12-534 m2g-1 for polymers obtained with toluene and 0-396 m2g-1 with the mixture of alcohols. Toluene enhanced the formation of micro- and mesopores, while the mixture of alcohols enhanced the creation of meso- and macropores. For the polymers prepared with toluene, their effectiveness in water purification decreases in the following order: DVB-GMA 2:1 > DVB-GMA 1:1 > DVB-GMA 1:2, according to the decreasing values of porous structure parameters. In the case of a series obtained with a mixture of alcohols, such correlation was not observed.

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Flexible, wearable pressure sensors offer numerous benefits, including superior sensing capabilities, a lightweight and compact design, and exceptional conformal properties, making them highly sought after in various applications including medical monitoring, human-computer interactions, and electronic skins. Because of their excellent characteristics, such as simple fabrication, low power consumption, and short response time, capacitive pressure sensors have received widespread attention. As a flexible polymer material, polydimethylsiloxane (PDMS) is widely used in the preparation of dielectric layers for capacitive pressure sensors. The Young's modulus of the flexible polymer can be effectively decreased through the synergistic application of sacrificial template and laser ablation techniques, thereby improving the functionality of capacitive pressure sensors. In this study, a novel sensor was introduced. Its dielectric layer was developed through a series of processes, including the use of a sacrificial template method using NaCl microparticles and subsequent CO2 laser ablation. This porous PDMS dielectric layer, featuring an array of holes, was then sandwiched between two flexible electrodes to create a capacitive pressure sensor. The sensor demonstrates a sensitivity of 0.694 kPa-1 within the pressure range of 0-1 kPa and can effectively detect pressures ranging from 3 Pa to 200 kPa. The sensor demonstrates stability for up to 500 cycles, with a rapid response time of 96 ms and a recovery time of 118 ms, coupled with a low hysteresis of 6.8%. Furthermore, our testing indicates that the sensor possesses limitless potential for use in detecting human physiological activities and delivering signals.

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Magnetic soft grippers have attracted intensive interest due to their untethered controllability, rapid response, and biological safety. However, manipulating living objects requires a simultaneous increase in shape adaptability and gripping force, which are typically mutually exclusive. Increasing the magnetic particle content enhances the magnetic strength but also increases the elastic modulus, leading to low adaptability and high impact force. Here, a porous magnetic soft gripper (PMSG) is developed by integrating a porous structure into a magnetic silicone elastomer. The design of porous hard magnetic composite is characterized by high magnetization, low modulus, and rough surface. It offers the PMSG good compliance, high gripping force, and low impact force at fast gripping. The PMSG is capable of performing a variety of tasks, including the fast and gentle grasping of delicate living objects. The study provides insight into the design of novel magnetic grippers and may offer a promising outlook for biomedical or scientific applications in the manipulation of delicate organisms.

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The rational design of visible-light-responsive catalysts is crucial for converting solar energy into hydrogen energy to promote sustainable energy development. In this work, a C─S─C bond is introduced into g-C3N4 (CN) through S doping. With the help of the flexible C─S─C bond under specific stimuli, a hollow coral-like porous structure of S-doped g-C3N4 (S-CN) is synthesized for the first time. And an S-doped g-C3N4/ZnIn2S4 (S-CN/ZIS) heterojunction catalyst is in situ synthesized based on S-CN. S0.5-CN/ZIS exhibits excellent photocatalytic hydrogen evolution (PHE) efficiency (19.25 mmol g-1 h-1), which is 2.7 times higher than that of the g-C3N4/ZnIn2S4 (CN/ZIS) catalyst (8.46 mmol g-1 h-1), with a high surface quantum efficiency (AQE) of 34.43% at 420 nm. Experiments and theoretical calculations demonstrate that the excellent photocatalytic performance is attributed to the larger specific surface area and porosity, enhanced interfacial electric field (IEF) effect, and appropriate hydrogen adsorption Gibbs free energy (ΔGH*). The synergistic effect of S doping and S-scheme heterojunction contributes to the above advancement. This study provides new insights and theoretical basis for the design of CN-based photocatalysts.