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Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Submitted/Accepted version Y.L., Z.L., M.Z., and X.C. acknowledge the National Research Foundation, Singapore (NRF) under NRF’s Medium Sized Centre: Singapore Hybrid-Integrated Next-Generation μElectronics (SHINE) Centre funding programme, and AME programming funding scheme of Cyber Physiochemical Interface (CPI) project (no. A18A1b0045). Y.L. acknowledges National Natural Science Foundation of China (62201243). C.J. acknowledges funding support from the National Key R&D Program of China (no. 2019YFA0706100), the National Natural Science Foundation of China (82151305), Lingang Laboratory (LG-QS-202202-09). T.Q.T. and N.E.L. acknowledge support by the Basic Science Research Program (no. 2020R1A2C3013480) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT. A.F. acknowledges the AFOSR (grant FA9550-22-1-0423). Y.L. and Y.Z. would like to acknowledge the NSF (award no. 2134664) and NIH (award no. R01HD108473) for financial support. X.F. acknowledges the support from the National Natural Science Foundation of China (grant no. U20A6001). L.Y. would like to thank the A*STAR Central Research Fund (CRF) and the AME Programmatic A18A1b0045 (Cyber Physiochemical Interfaces) for funding support. C.F.G. acknowledges the National Natural Science Foundation of China (no. T2225017). T.Q.T. acknowledges the Brain Pool Program (No. 2020H1D3A2A02111068) through the National Research Foundation (NRF) funded by the Ministry of Science. Z.L. acknowledges the support from RIE2020 AME Programmatic Grant funded by A*STAR-SERC, Singapore (Grant No. A18A1b0045). X.G. acknowledges funding support through the Shanghai Science and Technology Commission (grant no. 19JC1412400), the National Science Fund for Excellent Young Scholars (grant no. 61922057). C.D. acknowledges National Science Foundation CAREER: Conformable Piezoelectrics for Soft Tissue Imaging (grant no. 2044688) and MIT Media Lab Consortium funding. D.K. and O.G.S. acknowledge Leibniz Association and the German Research Foundation DFG (Gottfried Wilhelm Leibniz Program SCHM 1298/22-1, KA5051/1-1 and KA 5051/3-1), as well as the Leibniz association (Leibniz Transfer Program T62/2019). C.W. acknowledges the National Key Research and Development Program of China (grant no. 2021YFA1202600), National Natural Science Foundation of China (grant no. 62174082). A.V.-Y.T., E.Z., Y.Z., X.Z., and J.P. acknowledge the National Research Foundation, Singapore (NRF) under NRF’s Medium Sized Centre: Singapore Hybrid-Integrated Next-Generation μElectronics (SHINE) Centre funding programme, and AME programming funding scheme of Cyber Physiochemical Interface (CPI) project (no. A18A1b0045). R.Z. acknowledges National Natural Science Foundation of China (grant no. 51735007) and Beijing Natural Science Foundation (grant no. 3191001). N.M. acknowledges the support by JST PRESTO Grant Number JPMJPR20B7 and JST Adaptable and Seamless Technology transfer Program through Target-driven R&D (ASTEP) grant number JPMJTM22BK. C.P. acknowledges the Korean government (Ministry of Science and ICT, MSIT) (2022R1A4A3032923). M.W. acknowledges the National Key R&D Program of China under Grant (2021YFB3601200). X.Z. acknowledges National Natural Science Foundation of China (no. 62074029). S.X. acknowledges the 3M nontenured faculty award. T.-W.L. and D.-G.S. acknowledge the Pioneer Research Center Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (grant no. NRF-2022M3C1A3081211). C.T.L. would like to acknowledge support from the Institute for Health Innovation and Technology (iHealthtech), the MechanoBioEngineering Laboratory at the Department of Biomedical Engineering and the Institute for Functional Intelligent Materials (I-FIM) at the National University of Singapore (NUS). C.T.L. also acknowledges support from the National Research Foundation and A*STAR, under its RIE2020 Industry Alignment Fund − Industry Collaboration Projects (IAF-ICP) (grant no. I2001E0059) − SIA-NUS Digital Aviation Corp Lab and the NUS ARTIC Research (grant no. HFM-RP1). X.Y. acknowledges funding support by City University of Hong Kong (grant no. 9667221). T.X. and X.Z. acknowledge National Natural Science Foundation of China (22234006). B.C.K.T. acknowledges Cyber-Physiochemical Interfaces CPI, A*STAR A18A1b0045. H.G. acknowledges a research start-up grant (002479-00001) from Nanyang Technological University and the Agency for Science, Technology and Research (A*STAR) in Singapore. W.G. acknowledges National Science Foundation grant 2145802. D.J.L. acknowledges support from the US National Science Foundation grant number CBET-2223566. G.Y. acknowledges support from The Welch Foundation award F-1861, and Camille Dreyfus Teacher-Scholar Award. M.D.D. acknowledges funding support from NSF (grant no. EEC1160483). J.-H.A acknowledges the National Research Foundation of Korea (NRF-2015R1A3A2066337). J.C. acknowledges the Henry Samueli School of Engineering & Applied Science and the Department of Bioengineering at the University of California, Los Angeles for startup support and a Brain & Behavior Research Foundation Young Investigator Grant. K.T. acknowledges JST AIP Accelerated Program (no. JPMJCR21U1) and JSPS KAKENHI (grant no. JP22H00594). P.S.W. acknowledges the National Science Foundation (CMMI1636136) for support. A.M.A., M.C.H., and P.S.W. thank the National Institute on Drug Abuse (DA045550) for support. S.M. and X.C. appreciated the support from the Smart Grippers for Soft Robotics (SGSR) Programme under the National Research Foundation, Prime Minister’s Office, Singapore under its Campus of Research Excellence and Technological Enterprise (CREATE) programme.

Dip-pen nanolithography is an emerging and attractive surface modification technique that has the capacity to directly and controllably write micro/nano-array patterns on diverse substrates. The superior throughput, resolution, and registration enable DPN an outstanding candidate for biological detection from the molecular level to the cellular level. Herein, we overview the technological evolution of DPN in terms of its advanced derivatives and DPN-enabled versatile sensing patterns featuring multiple compositions and structures for biosensing. Benefitting from uniform, reproducible, and large-area array patterns, DPN-based biosensors have shown high sensitivity, excellent selectivity, and fast response in target analyte detection and specific cellular recognition. We anticipate that DPN-based technologies could offer great potential opportunities to fabricate multiplexed, programmable, and commercial array-based sensing biochips.

Shape-selective catalysis plays a key role in chemical synthesis. Porous nanomaterials with uniform pore structures are ideal supports for metal nanoparticles (MNPs) to generate efficient shape-selective catalysis. However, many commercial irregular porous nanomaterials face the challenge to realize satisfactory shape selectivity due to the lack of molecular sieving structures. Herein, we report a concept of creating shape selectivity in MNPs/porous nanomaterials through intentionally poisoning certain MNPs using suitable modifiers. The remaining MNPs within the substrates can cooperate with the channels to generate selectivity. Such a strategy not only applies to regular porous nanomaterials (such as MOFs, zeolites) but also extended to irregular porous nanomaterials (such as active carbon, P25). Potentially, the matching among different MNPs, corresponding modifiers, and porous nanomaterials makes our strategy promising in selective catalytic systems.

Constructing architectures with hierarchical porosity has been widely considered as the most efficient way to bypass the problems related to slow mass transfer and inaccessibility of internal space in MOFs. Now, a crystal-growth-dominated strategy is proposed to fabricate hierarchically porous MOFs (HP-MOFs). When the crystal growth is dominated by the monomer attachment, the aggregation of nonionic surfactant or polymer can be easily captured and released during the crystal growth process, resulting in the formation and ordering hierarchical pores along the radial direction. Owing to the accelerated mass diffusion and more exposed active sites of this design, HP-MOFs exhibited an enhanced catalytic efficiency in styrene oxidation.

A high charge overpotential and poor cycle stability are the limiting factors in lithium–oxygen (Li–O2) batteries, causing poor round-trip efficiency and cell failure. Many types of electrocatalyst...

Room temperature phosphorescent (RTP) materials are rising and gaining considerable attention due to their special photo-capture–release ability. Herein, a kind of environmentally friendly RTP composite was devised by microwaving a mixture of carbon dots, boric acid, and urea, in the presence of covalent bonds and hydrogen bonds between each of the components. The resultant RTP material showed ultra-long phosphorescence lifetime up to 1005.6 ms with an outstanding afterglow as long as 9.0 s. Moreover, this afterglow feature with moisture sensitive behavior was explored to achieve multilevel anti-counterfeiting, with the function of complex decryption of encrypted secret information under multiple stimuli. Our results provide a green strategy for scalable synthesis of carbon-based RTP materials, and extend their application scope to high level information security.

Pressure sensor can be applied in a wide range of fields, such as voice recognition, human motions detection and artificial electronic skin, the sensing of which is greatly influenced by the flexibility and stretchability of substrate materials. Here, based on the piezoresistive effect, new kinds of flexible pressure sensors have been realized from a pair of flexible and biocompatible collagen films: one is coated by silver nanowires (Ag NWs) and the other by interdigital electrode, respectively. The collagen films are regenerated from leather waste and could bring economic benefits to society. The prepared pressure sensors are applied for voice recognition and human motion detection. Graphical abstract A flexible pressure sensor based on two layers of regenerated collagen films coated silver nanowires (Ag NWs) and interdigital electrodes respectively are obtained. The flexible collagen films are prepared by dissolving leather waste into ionic liquid, [BMIM]Cl. The fabricated pressure sensor displays potential applications in voice recognition and human physical motion detection, such as finger and wrist bending-releasing, which are expected to access the training data of athletes, monitor some physical activities of patients synchronously and act as a voice recognition device.

Lithium–sulfur battery has drawn widely attention due to its high theoretical energy density, in addition to the abundant and affordable sulfur. However, the battery performances are still not satisfied due to the undesired shuttle effect of polysulfides, the sluggish reaction kinetics, together with the intrinsic non-conductivity of active materials. Thus, the preparation of sulfur host materials with polar, catalytic and conductive properties can be an effective tactics. In this work, a cobalt sulfide@reduced graphene oxide composite has been designed and synthesized by a facile method, in which the CoS nanoparticles can provide more polar and catalytic sites to adsorb the polysulfides and accelerate the kinetics of polysulfides conversion. The rGO can serve as composite skeleton that could not only enhance the conductivity of electrodes, but also provide a sheet structure, preventing the aggregation of CoS nanoparticles. Moreover, the C–S bonds between CoS and carbon can further promote charge transfer and stabilize the composite. Benefiting from the trifunctional sulfur-host, the as-prepared cathode exhibits low self-discharge, good cycling stability and high rate performance for 602.0 mAh g−1 at 2 C. This sulfur-host design can be considered an effective and simple strategy for advanced Li-S battery.

Nonaqueous lithium–oxygen batteries have attracted considerable attention due to their high energy density. Huge efforts have been made to unravel the fundamentals of Li–O2 battery chemistry. However, current Li–O2 batteries still suffer from several unresolved problems such as the instability of electrolytes and sluggish oxidation of lithium oxides during the charging process. In this work, we propose a detailed study to investigate the charge mechanism of lithium oxide materials in different electrolytes. Commercially available lithium peroxide and lithium oxide have been employed as cathodes to determine how lithium oxides (both lithium oxide and lithium peroxide) and electrolytes change during charge. The result shows that Li2O2 decomposed to lithium and oxygen; meanwhile, the electrolyte has a significant influence on Li2O2 decomposition. Furthermore, while most of the Li2O material participates in side reactions with the electrolyte, some of it is found to delithiate and crumble in structure.

Isostructural MOFs with similar crystallographic parameter are easily available for MOF-on-MOF growth and possible to form core–shell structure by isotropic growth. However, due to well-matched cell lattice, selective growth in isostructural MOF heterostructures remains a great challenge for engineering atypical MOF heterostructures. Herein, an anisotropic MOF-on-MOF growth strategy was developed to structure a range of multilayer sandwich-like ZIF-L heterostructures via stacking isostructural ZIF-L-Zn and ZIF-L-Co alternately with three-, five-, seven-, and more layer structures. Moreover, these heterostructures with highly designable feature were fantastic precursors for fabricating derivatives with tunable magnetic and catalytic properties. Such strategy explores a novel way of achieving anisotropic MOF-on-MOF growth between isostructural MOFs and opens up new horizons for regulating the properties by MOF modular assembly in versatile functional nanocomposites.

Sweat contains a broad range of critical biomarkers including ions, small molecules, and macromolecules that may indirectly or directly reflect the health status of the human body and thereby help track disease progression. Wearable sweat biosensors enable the collection and analysis of sweat in situ , achieving real-time, continuous, and noninvasive monitoring of human biochemical parameters at the molecular level. This review summarizes the physiological/pathological information of sweat and wearable sweat biosensors. First, the production of sweat pertaining to various electrolytes, metabolites, and proteins is described. Then, the compositions of the wearable sweat biosensors are summarized, and the design of each subsystem is introduced in detail. The latest applications of wearable sweat biosensors for outdoor, hospital, and family monitoring are highlighted. Finally, the review provides a summary and an outlook on the future developments and challenges of wearable sweat biosensors with the aim of advancing the field of wearable sweat monitoring technology.

Through encapsulating functional materials, metal–organic framework (MOF) composites show extraordinary potential in various fields due to the excellent synergistic effects between the host and guests. However, many attracting functional species, such as enzymes, could be easily damaged during the synthesis of MOF composites. Herein we report a new strategy, namely pressure-amorphization-stimulation-recovery (PASR), in which crystalline MOFs were transferred to the amorphous MOFs at certain mechanical pressure, followed by recrystallization process to encapsulate functional species into MOF crystals. The reversible phase transition avoids high temperature, high ionic strength, strong acid/base conditions, etc., which is suitable for many types of functional species. To prove the feasibility of this method, enzymes, anti-cancer drugs, noble metal nanoparticles and other functional materials, have been trapped into MOFs using this strategy. The synthesized MOF composites can maintain 95.6% of the enzyme activity under the treatment of protease, or reach 40% drug loading, or achieve 98% size selectivity for olefins. This strategy has been extended to several types of MOF structures and it will pave a new way for designing MOF composites and developing further applications.

Self-healing on fractured surfaces of silicon carbide (SiC) is highly desirable, to avoid the catastrophic failure of high-performance devices working at extreme environments. Nevertheless, self-healing on a fractured surface of an amorphous and crystalline (AAC) composite structure of a brittle nanowire (NW) has not been demonstrated. In this study, self-healing is demonstrated on mismatched fractured surfaces of the AAC composite structure of a brittle solid for a SiC NW with a diameter of 187 nm. Fracture strength is 10.18 GPa for the AAC structure, recovering 11.7% after self-healing on its mismatched fractured surfaces. To the best of our knowledge, we firstly report the self-healing on mismatched fractured surfaces of the AAC structure for a brittle NW. This is a breakthrough of the previous prediction that self-healing could not be realized on a brittle NW with a diameter over 150 nm. A growth of 3 nm was found after self-healing on the gap induced by mismatched fractured surfaces, which is different from previous reports for pure amorphous and monocrystalline brittle NWs. To reduce the potential energy, coherent rebonding and debonding were performed to realize the atomic migration to fill the gap, resulting in the growth of gap of 3 nm to perform self-healing. Our findings shed light on the potential of self-healing for design and fabrication of next-generation high-performance SiC devices used in the vacuum and aerospace industries.

Covalent organic frameworks (COFs) allow elaborate manufacture of ordered one‐dimensional channels in the crystal. We defined a superlattice of COFs by engineering channels with a persistent triangular shape and discrete pore size. We observed a size‐recognition regime that is different from the characteristic adsorption of COFs, whereby pore windows and walls were cooperative so that triangular apertures sorted molecules of one‐atom difference and notch nanogrooves confined them into single‐file molecular chains. The recognition and confinement were accurately described by sensitive spectroscopy and femtosecond dynamic simulations. The resulting COFs enabled instantaneous separation of mixtures at ambient temperature and pressure. This study offers an approach to merge precise recognition, selective transport, and instant separation in synthetic 1D channels.

Metal–organic frameworks (MOFs) and nanocellulose represent emerging and traditional porous materials, respectively. The combination of these two materials in specific ways could generate novel nanomaterials with integrated advantages and versatile functionalities. This study outlines the development of hierarchical porous and conductive nanosheets based on zeolitic imidazolate framework-67 (ZIF-67, a Co-based MOF)-templated Co–Ni layered double hydroxide (LDH) nanocages, Cladophora cellulose (CC) nanofibers, and multi-walled carbon nanotubes (CNTs). The LDH–CC–CNT nanosheets can be used as flexible and foldable electrodes for energy storage devices (ESDs). The electrodes are associated with a high areal capacitance of up to 1979 mF cm−2 at a potential scan rate of 1 mV s−1. A flexible, foldable, and hybrid ESD is assembled from LDH–CC–CNT and CC–CNT electrodes with a PVA/KOH gel. The entire device has an areal capacitance of 168 mF cm−2 and an energy density of 0.6 mW h cm−3 (60 μW h cm−2), at a power density of 8.0 mW cm−3 (0.8 mW cm−2). These promising results demonstrate the potential of using MOFs and sustainable cellulose in flexible, foldable electronic energy storage devices. De 2 första författarna delar förstaförfattarskapet.

With the development of flexible devices, the demand for wearable power sources has increased and gradually become imperative. Zinc-air batteries (ZABs) have attracted lots of research interest due to their high theoretical energy density and excellent safety properties, which can meet the wearable energy supply requirements. Here, the flexibility of energy storage devices is discussed first, followed by the chemistries and development of flexible ZABs. The design of flexible electrodes, the properties of solid-state electrolytes (SSEs), and the construction of deformable structures are discussed in depth. The researchers working on flexible energy storage devices will benefit from the work.

The electrocatalytic nitrogen reduction reaction (NRR) is known as a promising mean of nitrogen fixation to mitigate the energy crisis and facilitate fertilizer production under mild circumstances. For electrocatalytic reactions, the design of efficient catalysts is conducive to reducing activation energy and accelerating lethargic dynamics. Among them, hollow structural materials possess cavities in their structures, which can slack off the escape rate of N2 and reaction intermediates, prolong the residence time of N2, enrich the reaction intermediates’ concentration, and shorten electron transportation path, thereby further enhancing their NRR activity. Here, the basic synthetic strategies of hollow structural materials are introduced first. Then, the recent breakthroughs in hollow structural materials as NRR catalysts are reviewed from the perspective of intrinsic, mesoscopic, and microscopic regulations, aiming to discuss how structures affect and improve the catalytic performance. Finally, the future research directions of hollow structural materials as NRR catalysts are discussed. This review is expected to provide an outlook for optimizing hollow structural NRR catalysts., Recent progresses about the advantages of hollow structural materials for nitrogen reduction reaction are summarized. Besides, the top‐down fine regulating strategies from the perspective of intrinsic, mesoscopic, and microscopic regulations are introduced, aiming to discuss how various structures affect and improve the catalytic performance. These outputs render hollow structural materials to be the centerpiece for various applications, especially energy conversion applications.

Three-dimensional nanoporous carbon frameworks encapsulated Sn nanoparticles (Sn@3D-NPC) are developed by a facile method as an improved lithium ion battery anode. The Sn@3D-NPC delivers a reversible capacity of 740 mAh g–1 after 200 cycles at a current density of 200 mA g–1, corresponding to a capacity retention of 85% (against the second capacity) and high rate capability (300 mAh g–1 at 5 A g–1). Compared to the Sn nanoparticles (SnNPs), such improvements are attributed to the 3D porous and conductive framework. The whole structure can provide not only the high electrical conductivity that facilities the electron transfer but also the elasticity that will suppress the volume expansion and aggregation of SnNPs during the charge and discharge process. This work opens a new application of metal–organic frameworks in energy storage.

This report describes a facile strategy to enhance the catalytic selectivity by tuning the pore sizes of metal-organic frameworks (MOFs) in nanoparticles (NPs)/MOF composite catalysts. A general post-synthetic modification method was used to adjust the pore sizes of MOFs by using anhydrides with different chain lengths to react with amino groups in the ligands. The modified NPs/MOF catalysts exhibited enhanced size selectivity performance in the hydrogenation of olefins, which revealed the flexibility of MOFs as supporting materials for heterogeneous catalysis. Ministry of Education (MOE) Nanyang Technological University Accepted version This work was financially supported by the National Key R&D Program of China (2017YFA0207201), the National Natural Science Foundation (21574065, 21604038), the National Science Foundation for Distinguished Young Scholars (21625401), MOE under AcRF Tier 2 (MOE2015-T2-2-057; MOE2016-T2-2- 103; MOE2017-T2-1-162) and AcRF Tier 1 (2016-T1-002-051; 2017-T1-001-150; 2017-T1-002-119), NTU under Start-Up Grant (M4081296.070.500000) in Singapore, ITC via Hong Kong Branch of National Precious Metals Material Engineering Research Center, and the Start-Up Grant from City University of Hong Kong.

Covalent organic frameworks (COFs) allow elaborate manufacture of ordered one-dimensional channels in the crystal. We defined a superlattice of COFs by engineering channels with a persistent triangular shape and discrete pore size. We observed a size-recognition regime that is different from the characteristic adsorption of COFs, whereby pore windows and walls were cooperative so that triangular apertures sorted molecules of one-atom difference and notch nanogrooves confined them into single-file molecular chains. The recognition and confinement were accurately described by sensitive spectroscopy and femtosecond dynamic simulations. The resulting COFs enabled instantaneous separation of mixtures at ambient temperature and pressure. This study offers an approach to merge precise recognition, selective transport, and instant separation in synthetic 1D channels.

Electronic skin (e‐skin), an important part toward the realization of artificial intelligence, has been developing through comprehending, mimicking, and eventually outperforming skin in some aspects. Most of the e‐skin substrates are flexible polymers, such as polydimethylsiloxane (PDMS). Although PDMS was found to be biocompatible, it is not suitable for long‐time wearing due to its air impermeability. This study reports a simple and designable leather based e‐skin by merging the natural sophisticated structure and wearing comfort of leather with the multifunctional properties of nanomaterials. The leather based e‐skin could make leather, “the dead skin,” repurposed for its sensing capabilities. This e‐skin can be applied in flexible pressure sensors, displays, user‐interactive devices, etc. It provides a new class of materials for the development of multifunctional e‐skin to mimic or even outshine the functions of real skin.

Metal-organic frameworks (MOFs) have drawn increasing attentions as promising candidates for functional devices. Herein, we present MOF films in constructing memory devices with alcohol mediated resistance switching property, where the resistance state is controlled by applying alcohol vapors to achieve multilevel information storage. The ordered packing mode and the hydrogen bonding system of the guest molecules adsorbed in MOF crystals are shown to be the reason for the alcohol mediated electrical switching. This chemically mediated memory device can be a candidate in achieving environment-responsive devices and exhibits potential applications in wearable information storage systems. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) Accepted version

A facile encapsulation strategy for the preparation of metal layer/metal–organic framework (metal/MOF) hybrid thin films, by alternately growing MOF thin films and sputter-coating metal layers, is reported. The controlled species of the MOF thin films and metal layers, as well as the designed thickness of MOF thin films, endow the resulting hybrid thin films with improved functional and design flexibility. Importantly, the metal/MOF hybrid thin films, with well-defined sandwich structures, exhibit excellent selective catalytic activity, derived from MOFs acting as molecular sieves and the metal layers providing active sites.

Internal concentration polarization (ICP) in substrate layer is one of the most critical bottlenecks of the forward osmosis (FO) process. In this study, we explored the use of metal–organic frameworks (MOFs) as a removable filler to prepare MOF-based porous matrix membranes (PMMs) for improving the mass transfer in the FO substrates and hence controlling the ICP. MOF-based porous matrix substrates (PMSs) with three different types of MOFs were prepared via phase inversion by adding MOF particles into the polyacrylonitrile (PAN) dope solution. A thin selective layer was prepared using a layer-by-layer (LbL) deposition method on top of the porous matrix FO substrate. The bond dissociation energy (BDE) between metal ions and organic linker of MOF particles played an important role for the selection of fillers of PMMs. For MOF particles with lower BDE (

Stretchability plays an important role in wearable devices. Repeated stretching often causes the conductivity dramatically decreasing due to the damage of the inner conductive layer, which is a fatal and undesirable issue in this field. Herein, a convenient rolling strategy to prepare conductive fibers with high stretchability based on a spiral structure is proposed. With the simple rolling design, low resistance change can be obtained due to confined elongation nof the gold thin-film cracks, which is caused by the encapsulated effect in such a structure. When the fiber is under 50% strain, the resistance change (R/R0) is about 1.5, which is much lower than a thin film at the same strain (R/R0 ≈ 10). The fiber can even afford a high load strain (up to 100%), but still retain good conductivity. Such a design further demonstrates its capability when it is used as a conductor to confirm signal transfer with low attenuation, which can also be woven into textile to fabricate wearable electronics. MOE (Min. of Education, S’pore)

In this research, NiAl particles modified Al2O3 composites with toughening and crack-healing performances were prepared by spark plasma sintering. The toughening effects as a function of the NiAl particle size and content were systematically investigated. The fracture toughness was increased by 80% compared with pure alumina after incorporation of 1 μm NiAl particles at 15 wt%. A self-healing process of damaged composites induced by indentation was found to occur, mediated by oxidation of NiAl at elevated temperatures with the size of the NiAl particles. Atomic force microscopy was adopted to characterize the crack-healing performance and to explore the healing mechanism under each healing condition. The best crack-healing efficiency of 99.2% was found in the composite containing 1 μm NiAl at 15 wt% that was annealed at 1300°C for 5 h. In addition, the fracture toughness of the composite was further enhanced by 40% after the crack-healing process. These multifunctional ceramic composites may have promising and broad application in areas such as thermal barrier coatings, fuel cell membranes, etc.

The high performance of lithium-ion battery (LIB) electrodes relies largely on the meticulous design of hierarchical nanostructures with optimal balance between superior electrochemical properties and conductivity. Herein, we present a facile and cost-effective solvothermal method to fabricate a porous NiCo2O4/NiO hollow dodecahedron using zeolitic imidazolate framework-67 (ZIF-67) as both a precursor and a self-sacrificing template. Accurate control between the template etching and the precipitation of the shells is crucial to the preparation of the perfect nanocages. Serving as LIB anode materials, such metal–organic framework derived multiple transition metal oxides demonstrate a high reversible capacity of 1535 mA h g−1 at 0.2 A g−1 and a good cycling stability (97.2% retention after 100 cycles). The presented strategy represents a general route to synthesize various hierarchically interconnected and porous nanostructures of mixed transition metal oxides which are promising for a range of applications. ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version