Organic-inorganic covalent-ionic molecules for elastic ceramic plastic

Revealing Transition State Stabilization in Organocatalytic Ring-Opening Polymerization Using Data Science

In nature, enzymes leverage constituent amino acid residues to create catalytically active sites to effect high reactivity and selectivity. Multicomponent host-guest assemblies have been exploited to mimic enzymatic microenvironments by pre-organizing a network of noncovalent interactions. While organocatalysts such as thioureas have gained widespread success in organic transformation and controlled polymerization, evaluation of the participating structural features in the transition state (TS) remains challenging. Herein, we report the use of data science tools, i.e., a decision-tree-based machine-learning algorithm and Shapley additive explanations (SHAP) analysis, to model reactivity and regioselectivity in a thiourea-catalyzed ring-opening polymerization of 1,2-dithiolanes. Variation of aryl substituent position and electronic characteristics reveals key catalyst features involved in the TS. The analysis of feature importance helps explain the reason behind the optimal performance of (pseudo)halogen-substituted catalysts. Furthermore, the structural basis for the unveiled reactivity-regioselectivity trade-off in the catalysis are established.

Ultrafine PtGa Clusters Confined in Porous ZrOx/SiO2 Nanofibers for Enhanced Propane Dehydrogenation

Ultrafine Pt clusters exhibit superior activity for propane dehydrogenation compared to larger Pt nanoparticles; however, they are prone to sintering at high operating temperatures, leading to a decline in both activity and selectivity. In this work, porous ZrOx/SiO2 nanofibers featuring highly dispersed ZrOx nanodomains within a SiO2 matrix were successfully fabricated via a high-throughput blow-spinning process. The abundant and thermal-stable 1.6 nm micropores significantly stabilize 1.5 nm PtGa clusters against sintering at temperatures over 800 °C, due to the pore confinement. Moreover, the electron transfer from Ga to Pt is significantly enhanced in close proximity to ZrOx, contributing to metallic Pt with exceptional activity toward C-H bond activation. Thereby, the sinter-resistant PtGa/ZrOx/SiO2 nanofibers maintained 98.8% propylene selectivity and 43.2% propane conversion rate over 100 h of reaction, with a deactivation rate constant down to 0.0045 h-1. This work explores a sinter-resistant catalytic system based on oxide nanofibers and elaborates a new logic for the design of high-performance propane dehydrogenation catalysts with long-term stability.

Inorganic-organic hybrid metamaterials with switchable high stiffness and elasticity

In the pursuit of replicating the remarkable mechanical properties of natural biological composites like bone and seashell, developing artificial bulk materials that seamlessly integrate rigid inorganic components with ductile organic constituents has been a longstanding challenge. A key hurdle has been the establishment of robust and reliable linkages between these disparate building blocks. Mechanical metamaterials achieved by well-designed chemical structures, however, offer a promising solution to address this challenge. In this study, we demonstrate that the calcium phosphate-based inorganic-organic hybrid metamaterials trapping inorganic nanoparticles within long-chain polymeric networks and anchoring inorganic blocks to these networks via short-chain organic crosslinkers exhibit switchable and tunable high stiffness and elasticity. Additionally, these metamaterials not only exhibit peculiar mechanical characteristics, but also present excellent biocompatibility, as demonstrated by the in vivo tests using male rats and the in vitro tests. These results suggest a wide range of potential clinical applications.

Micrometer-scale poly(ethylene glycol) with enhanced mechanical performance

Strong and lightweight materials are highly desired. Here we report the emergence of a compressive strength exceeding 2 GPa in a directly printed poly(ethylene glycol) micropillar. This strong and highly crosslinked micropillar is not brittle, instead, it behaves like rubber under compression. Experimental results show that the micropillar sustains a strain approaching 70%, absorbs energy up to 310 MJ/m3, and displays an almost 100% recovery after cyclic loading. Simple micro-lattices (e.g., honeycombs) of poly(ethylene glycol) also display high strength at low structural densities. By combining a series of control experiments, computational simulations and in situ characterization, we find that the key to achieving such mechanical performance lies in the fabrication of a highly homogeneous structure with suppressed defect formation. Our discovery unveils a generalizable approach for achieving a performance leap in polymeric materials and provides a complementary approach to enhance the mechanical performance of low-density latticed structures.

Interface Engineering for High Strength and High Toughness Ceramic Matrix Composites

Ceramics exhibit exceptional strength, hardness, and structural stability, rendering them indispensable as aerospace, national defense and biomedical applications. However, the presence of robust covalent or ionic bonds within the ceramic leads to its inherent poor fracture toughness. The incorporation of toughening phases into ceramics is widely recognized as an optimal toughening strategy for ceramic matrix composites (CMCs) based on chemical means, with the interplay between toughening phase and ceramic at the interface playing a crucial role in achieving superior mechanical properties. In this review, we briefly delineate the evolution of ceramic matrix composites, emphasizing that interface engineering constitutes an efficacious approach to augmenting the fracture toughness of these composites. Furthermore, we meticulously explore the structure-activity relationship between the composition and structure of the toughening phase and the mechanical attributes of CMCs. Additionally, we comprehensively summarize the impact of innovative biomimetic structures on the mechanical properties of these composites, unveiling the beneficial effects of interface regulation on energy dissipation. Ultimately, we systematically consolidate the mechanisms underpinning the influence of interface engineering on the mechanical properties of CMCs and propose solutions to existing interface challenges, paving the way for the development of next-generation CMCs that exhibit unparalleled strength and toughness.

Hierarchical Engineering of Single-Crystalline Mesoporous Metal-Organic Frameworks with Hollow Structures

Although the superiority of hierarchical structure has driven extensive demand for applications, establishing hierarchy in a long-range-ordered single crystal remains a formidable challenge due to the inherent competition and contradiction between single crystallinity and controllable hierarchical structure. Herein, we demonstrate a growth and dissociation kinetics cooperative strategy for synthesizing a family of hollow single-crystalline mesoporous metal-organic frameworks (meso-MOFs) with hierarchical structures. The approach employs a dual-template method, integrating both hard and soft templates. By adjusting the HCl/CH3COOH ratio, the reaction system's pH can be tuned to regulate the dissociation kinetics of the acid-sensitive seeds serving as hard templates for the formation of hollow structure, while simultaneously modifying the concentration of the dual acids to control the growth kinetics of meso-MOF shells. The competition between maintaining a single crystallinity and achieving a well-defined hierarchical structure can be effectively balanced. Driven by the two interfacial kinetics, we successfully obtained the octahedral meso-MOF nanoparticles that not only exhibit a well-defined hollow structure with precisely controllable hollow size (∼81-1120 nm) and tunable wall thickness (∼28.6-61.3 nm) but also retain their single-crystal integrity. Specifically, the dissociation kinetics of seeds governed the formation of hollow structures, while the growth kinetics of single-crystalline meso-MOF shells ensured uniform coverage and structural integrity. Based on this strategy, we further developed a series of novel hollow meso-MOFs with hierarchical nanostructures, including hollow open-capsule meso-MOFs, 2D hollow meso-MOFs, hollow interlayer-structured meso-MOFs, macro-meso-micro trimodal porous MOFs, and so on.

Adding Value into Elementary Sulfur for Sustainable Materials

Sulfur-rich copolymers, characterized by high sulfur contents and dynamic disulfide bonds, show significant promise as sustainable alternatives to conventional carbon-based plastics. Since the advent of inverse vulcanization in 2013, numerous synthesis strategies have emerged - ranging from thermopolymerization and photoinduced polymerization to the use of crosslinkers such as mercaptans, episulfides, benzoxazines, and cyclic disulfides. These advancements coupled with the rising demand for degradable plastics have driven research for diverse applications, including optical windows, metal uptake, and adhesives. Due to the unique electronic properties of sulfur-rich materials, they are promising candidates for cathodes in Li-S batteries and triboelectric nanogenerators. This review highlight the latest exciting ways of synthesis strategy in which sulfur and sulfur-based reactions are bing utilized to produce sustainable materials in energy, optics, engeneering material, environemtal, and triboelectric nanogenerators. Finally, this review provides a forward-looking perspective on the opportunities and challenges shaping this rapidly evolving field.

A 3D Hybrid Perovskite Ferroelastic with Triclinic-to-Cubic Phase Transition Boosts Temperature/Pressure Dual On/Off Switchable Birefringence

Birefringent crystals have gained enormous attention for decades due to their unique ability to manipulate polarized light. However, achieving the fascinating on/off (active/inactive) switchable birefringence under external stimuli in crystals remains a huge challenge, and the stimuli employed have been constrained predominantly to temperature. Here, through H/F substitution, we designed a 3D hybrid double perovskite ferroelastic [C3H5FNH2]2[(NH4)Fe(CN)6] (1-F), which undergoes am 3 ¯ m F 1 ¯ $m {\mathrm{\bar{3}}}m{\mathrm{F}}{\mathrm{\bar{1}}}$ ferroelastic transition at 296 K, with the highest possible orientation states of 24 among ferroelastic crystals. Notably, the ferroelastic phase transition of 1-F can also be triggered by pressure with a low critical pressure of ∼0.3 GPa. More importantly, 1-F shows the unprecedented temperature/pressure dual stimuli-induced on/off switching of birefringence between the birefringence-active state in the anisotropic triclinic ferroelasticP 1 ¯ $P{\mathrm{\bar{1}}}$ phase and the birefringence-inactive state in the isotropic cubic paraelasticF m 3 ¯ m $Fm{\mathrm{\bar{3}}}m$ phase during them 3 ¯ m F 1 ¯ $m{\mathrm{\bar{3}}}m{\mathrm{F}}{\mathrm{\bar{1}}}$ ferroelastic transition. To the best of our knowledge, this is the first report of dual stimuli-induced switchable birefringence in crystals. Our work paves a new way for the switching of birefringence and sheds light on the further exploration of switchable birefringence in ferroelastics.

A Capping-assisted Strategy for Synthesis of Glass-like Carboxylate-biased Coordination Polymers

The direct preparation of glass-like carboxylate-based coordination polymers (CPs) possessing continuous internal structure and transparency is challenging due to the lack of control on coordination kinetics and subsequently the range of order. Herein, a capping-assisted strategy was presented to control the molecular assembly during the metal-ligand coordination in the solution and to inhibit the long-range of order hence building glass-like CPs (g-CPs) mimicking the polymerization process. 1,3,5-benzene tricarboxylate (BTC) ligand was used to connect the copper cations (Cu2+) into metal-organic complexes of different Cu: BTC ratios (metal-organic pool) in presence of an excess of triethyl amine as a capping agent. Concentrating the Cu-BTC complexes and further drying under mild conditions induced the decapping process which triggered the random crosslinking between the free carboxylate and Cu2+ to form a boundary-free continuous internal structure. The as-prepared Cu-BTC g-CP exhibited an approximately similar fine structure like its crystalline counterpart (HKUST-1), which facilitated solvent and thermal-induced crystallization. Due to the internal structure continuity, the g-CP possesses ceramic-like hardness and wear resistance and plastic-like resilience. This capping-assisted strategy has been successfully extended to Ni-BTC and Fe-BTC systems under mild conditions and thus presenting a general method for the formation of glass-like carboxylate-based CPs.

Hybrid Soft Segments Boost the Development of Ultratough Thermoplastic Elastomers with Tunable Hardness

The hardness of thermoplastic elastomers (TPEs) significantly influences their suitability for various applications, but traditionally, enhancing hardness reduces toughness. Herein a method is introduced that leverages hybrid soft segments to fine-tune the hardness of TPEs without compromising their exceptional toughness. Through the selective copolymerization of polytetramethylene ether glycols (PTMEGs) at various molecular weights, supramolecular poly(urethane-urea) TPEs are molecularly engineered to cover a wide spectrum of hardness while retaining good toughness. It is achieved through the formation of graded functional zones-densely packed for enhanced hardness and strength, and loosely packed for greater extensibility and toughness-driven by variations in PTMEG chain length and mismatched supramolecular interactions. Through the establishment and systematic investigation of a TPE library, the intricate interplay between design, structure, and performance of these materials is elucidated, refining the optimization techniques. The TPEs demonstrate exceptional mechanical properties, including a variant with a Shore hardness of 86A and a toughness of 819 MJ m-3, alongside a softer variant with a 59A hardness and a 786 MJ m-3 toughness. The innovation extends to a scalable solvent-based TPE production line, promising widespread industrial application. This advancement reimagines the potential of high-performance TPEs and composites, offering versatile materials for demanding applications.

High-Temperature Oxidation-Resistant Phenolic-Based Hybrids Enabled by Novel Organic-Inorganic Covalent-Ionic Bicontinuous Network

Organic-inorganic thermosetting hybrids, featuring unique self-ceramization abilities and excellent thermal-oxidative stabilities, are garnering substantial interest as candidates for thermal protection in extreme environments. However, designing a groundbreaking hybrid with a molecular-scale bicontinuous network remains a formidable challenge. In this work, a novel approach is proposed to prepare bicontinuous thermosetting hybrids with the aid of an organic-inorganic covalent-ionic molecule: 3-carboxyphenylboronic acid (3-CPBA) functionalized calcium phosphate oligomer (CPO), named 3-BAPO. By tailoring the supramolecular interactions between 3-BAPO and boron-phenolic resin (BPR), a series of hybrid precursors is successfully obtained, designated 3-BRPO, with varying inorganic contents (13.5-25.9 wt%). The hybrid precursors undergo concurrent inorganic ionic crosslinking and organic phenolic curing synchronously under reasonable conditions, resulting in the formation of a covalent-ionic bicontinuous network. Multiple chemical interactions between the organic and inorganic components drive the formation of this network, imparting superior high-temperature oxidation resistance to the 3-BRPO hybrids, achieved by in situ ceramization of the continuous inorganic phase at ultrahigh temperatures. This work demonstrates a novel strategy to avoid the separate nucleation of the organic and inorganic phases in thermosetting hybrids by employing organic-functionalized ionic oligomers as inorganic components, providing a promising platform for the molecular engineering of advanced hybrid materials.

Beryllium-Based ABX3-Type Organic-Inorganic Hybrid Halide Ferroelastic

Organic-inorganic hybrid ferroelastic materials attract great interest in multiple application scenarios, including data storage, shape memory, actuators, mechanical switches, etc. Despite hybrid molecular ferroelastics being the subject of extensive studies due to their remarkable structural and compositional versatility, hybrid metal halide ferroelastics composed of group IIA metal elements have rarely been reported up to now. Herein, a beryllium (Be)-based hybrid halide ABX3-type ferroelastic, CBA-BeF3 (CBA = cyclobutylamine), has been reported for the first time. CBA-BeF3 demonstrates an order-disorder structural phase transition at 356 K, accompanied by a distinct change in symmetry that belongs to the paraelastic-ferroelastic transition with an Aizu notation of mmmF2/m. The observation of ferroelastic domain evolution and stress-strain hysteresis phenomena indicates the ferroelastic nature of CBA-BeF3. This work showcases a brand-new family of hybrid halide ferroelastics and is of great inspiration to explore more group IIA metal-based ferroelastic materials.

Bioinspired Materials for Controlling Mineral Adhesion: From Innovation Design to Diverse Applications

The advancement of controllable mineral adhesion materials has significantly impacted various sectors, including industrial production, energy utilization, biomedicine, construction engineering, food safety, and environmental management. Natural biological materials exhibit distinctive and controllable adhesion properties that inspire the design of artificial systems for controlling mineral adhesion. In recent decades, researchers have sought to create bioinspired materials that effectively regulate mineral adhesion, significantly accelerating the development of functional materials across various emerging fields. Herein, we review recent advances in bioinspired materials for controlling mineral adhesion, including bioinspired mineralized materials and bioinspired antiscaling materials. First, a systematic overview of biological materials that exhibit controllable mineral adhesion in nature is provided. Then, the mechanism of mineral adhesion and the latest adhesion characterization between minerals and material surfaces are introduced. Later, the latest advances in bioinspired materials designed for controlling mineral adhesion are presented, ranging from the molecular level to micro/nanostructures, including bioinspired mineralized materials and bioinspired antiscaling materials. Additionally, recent applications of these bioinspired materials in emerging fields are discussed, such as industrial production, energy utilization, biomedicine, construction engineering, and environmental management, highlighting their roles in promoting or inhibiting aspects. Finally, we summarize the ongoing challenges and offer a perspective on the future of this charming field.

Ring-Opening Polymerization of Surface Ligands Enables Versatile Optical Patterning and Form Factor Flexibility in Quantum Dot Assemblies

The evolution of display technologies is rapidly transitioning from traditional screens to advanced augmented reality (AR)/virtual reality (VR) and wearable devices, where quantum dots (QDs) serve as crucial pure-color emitters. While solution processing efficiently forms QD solids, challenges emerge in subsequent stages, such as layer deposition, etching, and solvent immersion. These issues become especially pronounced when developing diverse form factors, necessitating innovative patterning methods that are both reversible and sustainable. Herein, a novel approach utilizing lipoic acid (LA) as a ligand is presented, featuring a carboxylic acid group for QD surface attachment and a reversible disulfide ring structure. Upon i-line UV exposure, the LA ligand initiates ring-opening polymerization (ROP), crosslinking the QDs and enhances their solvent resistance. This method enables precise full-color QD patterns with feature sizes as small as 3 µm and pixel densities exceeding 3788 ppi. Additionally, it supports the fabrication of stretchable QD composites using LA-derived monomers. The reversible ROP process allows for flexibility, self-healing, and QD recovery, promoting sustainability and expanding QD applications for ultra-fine patterning and on-silicon displays.

"Frozen" Ionogels with High and Tunable Toughness for Soft Electronics

As a promising material, ionogels have garnered increasing interest in various applications including flexible electronics and energy storage. However, most existing ionogels suffer from poor mechanical properties. Herein, an effective and universal strategy is reported to toughen ionogels by freezing the polymer network via network design. As a proof of concept, an ionogel is readily prepared by copolymerization of isobornyl acrylate (IBA) and ethoxyethoxyethyl acrylate (CBA) in the presence of ionic liquid, resulting in a bicontinuous phase-separated structure. The rigid, ionic liquid-free PIBA segments remain frozen at service temperature and serve as a load-bearing phase to toughen ionogels, while the flexible PCBA phases maintain high ionic liquid content. As a result, the mechanical properties of ionogels are noticeably improved, showing high rigidity (48.5 MPa), strength (4.19 MPa), and toughness (8.19 MJ · m-3). Moreover, ionogels also exhibit remarkable thermo-softening performance, strong adhesiveness, high conductivity, shape memory properties, and satisfactory biocompatibility. When used as an ionic skin, the ionogel can not only respond to different deformation but also accurately and consistently detect body motions over long periods. This novel strategy in toughening ionogels can pave the way for the development of various tough and stable ionotronic devices.

Controllable Polymerization of Inorganic Ionic Oligomers for Precise Nanostructural Construction in Materials

The rational design of nanostructures is critical for achieving high-performance materials. The close-packing behavior of inorganic ions and their less controllable nucleation process impede the precise nanostructural construction of inorganic ionic compounds. The discovery of inorganic ionic oligomers (stable molecular-scale inorganic ionic compounds) and their polymerization reaction enables the controllable arrangement of inorganic ions for diverse nanostructures. This perspective aims to introduce inorganic ionic oligomers and their currently identified advantages in the precise design of inorganic and organic-inorganic hybrid nanostructures, directing the development of advanced materials with applications across the mechanical, energy, environmental, and biomedical fields. The challenges and opportunities for the controllable polymerization of inorganic ionic oligomers are presented at the end of this perspective. We suggest that inorganic ionic oligomers and their polymerization reaction offer a promising strategy for the preparation of inorganic and organic-inorganic hybrid materials.

Kinetic Control of Self-Assembly Pathway in Dual Dynamic Covalent Polymeric Systems

Kinetically controlled self-assembly is garnering increasing interest in the field of supramolecular polymers and materials, yet examples involving dynamic covalent exchange remain relatively unexplored. Here we report an unexpected dynamic covalent polymeric system whose aqueous self-assembly pathway is strongly influenced by the kinetics of evaporation of water. The key design is to integrate dual dynamic covalent bonds-including disulfide bonds and boroxine/borate-into a dynamic equilibrium system of monomers, polymers, and materials. This dual dynamic covalent design allows polymer growth and crosslinking to occur with the same spatiotemporal characteristics, governed solely by solvent evaporation. We found that a single building block can assemble into two distinct types of polymeric materials, each characterized by unique crosslinking topologies, orders, solubility, and macroscopic properties. The dual dynamic nature of the materials imparts them with intrinsic reconfigurability, such as interfacial repairability and close-loop chemical recyclability.

Bridging Biological Multiscale Structure and Biomimetic Ceramic Construction

The brittleness of traditional ceramics severely limits their application progress in engineering. The multiscale structural design of organisms can solve this problem, but it still lacks sufficient research and attention. The underlined main feature is the multiscale hierarchical structures composed of basic nano-microstructure units arranged in order, which is currently impossible to achieve through artificial synthesis driven by high temperatures. This perspective aims to bridge the gap between biostructural materials and biomimetic ceramics, highlighting the relationship between bioinspired structures and interfacial interaction of structure densification in biomimetic ceramics. Therefore, we could accomplish densification and ceramic development at room temperature, consequently correlating the structure, properties, and functions of materials and accelerating the development of the next generation of advanced functional ceramics.

Intrinsic Anti-Freezing, Tough, and Transparent Hydrogels for Smart Optical and Multi-Modal Sensing Applications

Hydrogels have received great attention due to their molecular designability and wide application range. However, they are prone to freeze at low temperatures due to the existence of mass water molecules, which can damage their flexibility and transparency, greatly limiting their use in cold environments. Although adding cryoprotectants can reduce the freezing point of hydrogels, it may also deteriorate the mechanical properties and face the risk of cryoprotectant leakage. Herein, the microphase-separated structures of hydrogels are regulated to confine water molecules in sub-6 nm nanochannels and increase the proportion of bound water, endowing the hydrogels with intrinsic anti-freezing properties, high mechanical strength, good stretchability, remarkable fracture energy, and puncture resistance. Even after being kept in liquid nitrogen for 1000 h, the hydrogel still maintains good transparency. The hydrogel can exhibit excellent low-temperature shape memory and intelligent optical waveguide properties. Additionally, the hydrogel can be assembled into strain and pressure sensors for flexible sensing at both room and low temperatures. The intrinsically anti-freezing microphase-separated hydrogel offers broad prospects in low-temperature electronic and optical applications.

A self-healing composite solid electrolyte with dynamic three-dimensional inorganic/organic hybrid network for flexible all-solid-state lithium metal batteries

Composite solid electrolytes (CSEs), which combine the advantages of solid polymer electrolytes and inorganic solid electrolytes, are considered to be promising electrolytes for all-solid-state lithium metal batteries. However, the current CSEs suffer from defects such as poor inorganic/organic interface compatibility, lithium dendrite growth, and easy damage of electrolyte membrane, which hinder the practical application of CSEs. Herein, a CSE (PBHL@LLZTO@DDB) with polyurethane (PBHL) as the polymer matrix and Li6.4La3Zr1.4Ta0.6O12 (LLZTO) modified by silane coupling agent (DDB) as inorganic fillers (LLZTO@DDB) has been prepared. Disulfide bond exchange reactions between PBHL and LLZTO@DDB enable PBHL@LLZTO@DDB to form a dynamic three-dimensional (3D) inorganic/organic hybrid network, which promotes the uniform dispersion of LLZTO in PBHL@LLZTO@DDB, improves the Li+ conductivity (1.24 ± 0.08 × 10-4 S cm-1 at 30 ℃), and broadens the electrochemical stability window (5.16 V vs. Li+/Li). Moreover, a combination of hydrogen bonds and disulfide bonds endows PBHL@LLZTO@DDB with excellent self-healing properties. As such, both all-solid-state symmetric and full cells exhibit excellent cycle performance at ambient temperature. More importantly, the healed PBHL@LLZTO@DDB can almost completely restore its original electrochemical properties, indicating its application potential in flexible electronic products.

Calcium Carbonate as an Ionic Molecular Lock for Ultrastrong Fluorescence of Single Organic Molecules

Locking molecular conformation are widely applied in molecular engineering for improved performance. However, locking via organic functional groups often changes the original molecular properties. Following the rigidity and stability of ionic interaction in ionic compounds, we suggested the use of a molecular-scale ionic compound, calcium carbonate oligomer, as a robust molecular segment to functionalize organic molecules. The rigid structure of the ionic molecular segments locked the organic molecules, which could remarkably limit the intramolecular motion and intermolecular interactions. This ensured a stable and ultrastrong fluorescence of the single organic molecule while preserving its original maximum emission wavelength. The locking strategy was general and extendable to multiple organic molecules. Additionally, the ultrastrong single-molecular fluorescence can be maintained in inorganic solids with even higher quantum yields and almost unchanged maximum emission wavelength. The highest quantum yield of the investigated molecules reached 99.9 %, superior to all reported organic-inorganic fluorescent composite under air conditions. This work demonstrates a general strategy to restrict intramolecular motion and intermolecular interactions by using ionic oligomers as molecular locks, providing an alternative method for realizing ultraemissive molecules. This further demonstrates a fascinating example of molecular engineering in the presence of inorganic ionic molecules.

Construction of an In Situ-Generated Nanoscale Organic-Inorganic Hybrid System Using Hydrogen Bonding Interaction To Assist Thermal Properties of Resins

With the rapid development of science and technology, high-temperature-resistant resin systems are facing more severe challenges in extreme applications. To further improve the comprehensive thermal properties of phthalonitrile resins, an in situ generation of a high-temperature-resistant phthalonitrile resin achieving an organic-inorganic hybridization network is reported. A 3-aminophenol phthalonitrile containing -NH2 is used as a material to hybridize with prepared calcium phosphate nano-oligomers (CPOs), and the hybrid precursor is named as CAPN. Notably, the hydrogen bonding plays a crucial role in the hybrid, as nanosize control of CPOs, and in the synthesis of CAPN. The presence of hydrogen bonding interaction is proved by Fourier transform infrared, Raman, 31P solid-state nuclear magnetic resonance spectra, isothermal differential scanning calorimetric testing, and calculation of apparent activation energy (Ea). Based on organic-inorganic hybrid cross-linked networks formed by resins during the curing process, 50CAPN (the hybrid containing 50 wt % CPOs) has superior thermo-mechanical properties [glass transition temperature (Tg) > 580 °C] and thermal stability [5% pyrolysis temperature (Td5%(N2) = 574 °C, Td5%(air) = 543 °C)] than the blending system 50HAPN [the mixture with 50 wt % nanohydroxyapatite (HAP)]. Additionally, under extreme high temperature and combustion conditions, it demonstrates that 50CAPN has more stable thermo-oxidative aging resistance and flame retardancy than 50HAPN. We believe that this organic-inorganic hybrid system of phthalonitrile formed based on hydrogen bonding will elevate the introduction of the inorganic phase into the organic phase for the preparation of high-temperature-resistant resin systems to a certain level.

High-entropy non-covalent cyclic peptide glass

Biomolecule-based non-covalent glasses are biocompatible and biodegradable, and offer a sustainable alternative to conventional glass. Cyclic peptides (CPs) can serve as promising glass formers owing to their structural rigidity and resistance to enzymatic degradation. However, their potent crystallization tendency hinders their potential in glass construction. Here we engineered a series of CP glasses with tunable glass transition behaviours by modulating the conformational complexity of CP clusters. By incorporating multicomponent CPs, the formation of high-entropy CP glass is facilitated, which-in turn-inhibits the crystallization of individual CPs. The high-entropy CP glass demonstrates enhanced mechanical properties and enzyme tolerance compared with individual CP glass and a unique biorecycling capability that is unattainable by traditional glasses. These findings provide a promising paradigm for the design and development of stable non-covalent glasses based on naturally derived biomolecules, and advance their application in pharmaceutical formulations and smart functional materials.

Recent Advances of Organic-Inorganic Hybrid Fluorescent Hyperbranched Polymer: Synthesis, Performance Regulation Strategies and Applications

The organic-inorganic hybrid fluorescent hyperbranched polymer, including hyperbranched polysiloxane and hyperbranched polyborate, have attracted much attention due to their excellent optical properties and wide range of applications. Hyperbranched polysiloxane and polyborates, prepared by introducing Si or B elements into organic polymer chains at the molecular level through rational molecular design and novel synthesis methods, exhibit outstanding photophysical properties as an indispensable branch of organic-inorganic hybrid fluorescent materials. Herein, this review highlights the recent research progress on hyperbranched polysiloxanes and hyperbranched polyborates, including strategies for regulating their emission wavelengths, quantum yields, and fluorescence lifetimes, potential emission mechanisms, and various applications. Finally, some challenges and promising future directions in the field of organic-inorganic hybrid fluorescent polymers are summarized.

Optically transparent and mechanically tough glass with impact resistance and flame retardancy enabled by covalent/supramolecular interactions

Exploring glass materials beyond inorganic components represents a new direction in the development of artificial transparent materials. Inspired by the successes of polymeric and supramolecular glasses, we shifted our attention to the preparation of a transparent glass through the polymerization of low-molecular-weight monomers that are naturally tailored with noncovalent recognition motifs. In this work, an imidazolium unit bearing a vinyl group and a tetrafluoroborate counter anion was selected to construct an artificial glass. Experimental and theoretical investigations revealed that the cross-linking behavior of anions effectively transformed linear polymeric chains into three-dimensional networks. The polymeric-supramolecular glass exhibits a tough tensile strength (61.31 MPa), high Young's modulus (1.17 GPa), and good optical transparency (>90%), which are comparable to those of polymethyl methacrylate. Moreover, the obtained glass maintains excellent mechanical toughness and optical transparency over a wide temperature range (from -150 to 150 °C). The material shows a superior impact resistance (18.34 kJ m-2) and flame retardancy (V0 rating), which are barely achieved by supramolecular materials.

Organic-inorganic covalent-ionic network enabled all-in-one multifunctional coating for flexible displays

Touch displays are ubiquitous in modern technologies. However, current protective methods for emerging flexible displays against static, scratches, bending, and smudge rely on multilayer materials that impede progress towards flexible, lightweight, and multifunctional designs. Developing a single coating layer integrating all these functions remains challenging yet highly anticipated. Herein, we introduce an organic-inorganic covalent-ionic hybrid network that leverages the reorganizing interaction between siloxanes (i.e., trifluoropropyl-funtionalized polyhedral oligomeric silsesquioxane and cyclotrisiloxane) and fluoride ions. This nanoscale organic-inorganic covalent-ionic hybridized crosslinked network, combined with a low surface energy trifluoropropyl group, offers a monolithic layer coating with excellent optical, antistatic, anti-smudge properties, flexibility, scratch resistance, and recyclability. Compared with existing protective materials, this all-in-one coating demonstrates comprehensive multifunctionality and closed-loop recyclability, making it ideal for future flexible displays and contributing to ecological sustainability in consumer electronics.

Macrocyclic Supramolecular Glass: New Type of Supramolecular Transparent Materials

Transparent materials are widely used in industries, everyday life, and scientific activities. The development of new, lightweight, and durable artificial transparent materials is a challenge in synthetic chemistry. In this study, a supramolecular approach is conceived to construct transparent glass. Cyclodextrins are selected as the building blocks for the fabrication of supramolecular glass via noncovalent polymerization. The newly formed glass displays several attractive advantages, including good thermal processability, high mechanical strength and dielectric constant, excellent visible light transparency, and good adhesion performance. Importantly, the structural characteristics of long-range disorder and short-range order are observed in cyclodextrin glass. Here a new strategy is presented for the preparation and functionalization of low-molecular-weight transparent materials.

Polyfunctional and Multisensory Bio-Ionoelastomers Enabled by Covalent Adaptive Networks With Hierarchically Dynamic Bonding

Developing versatile ionoelastomers, the alternatives to hydrogels and ionogels, will boost the advancement of high-performance ionotronic devices. However, meeting the requirements of bio-derivation, high toughness, high stretchability, autonomous self-healing ability, high ionic conductivity, reprocessing, and favorable recyclability in a single ionoelastomer remains a challenging endeavor. Herein, a dynamic covalent and supramolecular design, lipoic acid (LA)-based dynamic covalent ionoelastomer (DCIE), is proposed via melt building covalent adaptive networks with hierarchically dynamic bonding (CAN-HDB), wherein lithium bonds aid in the dissociation of ions and the integration of dynamic disulfide metathesis, lithium bonds, and binary hydrogen bonds enhances the mechanical performances, self-healing capability, reprocessing, and recyclability. Therefore, the trade-off among mechanical versatility, ionic conductivity, self-healing capability, reprocessing, and recyclability is successfully handled. The obtained DCIE demonstrates remarkable stretchability (1011.7%), high toughness (3877 kJ m-3), high ionic conductivity (3.94 × 10-4 S m-1), outstanding self-healing capability, reprocessing for 3D printing, and desirable recyclability. Significantly, the selective ion transport endows the DCIE with multisensory feature capable of generating continuous electrical signals for high-quality sensations towards temperature, humidity, and strain. Coupled with the straightforward methodology, abundant availability of LA and HPC, as well as multifunction, the DCIEs present new concept of advanced ionic conductors for developing soft ionotronics.

Dual Nanofillers Reinforced Polymer-Inorganic Nanocomposite Film with Enhanced Mechanical Properties

Simultaneously improving the strength and toughness of polymer-inorganic nanocomposites is highly desirable but remains technically challenging. Herein, a simple yet effective pathway to prepare polymer-inorganic nanocomposite films that exhibit excellent mechanical properties due to their unique composition and structure is demonstrated. Specifically, a series of poly(methacrylic acid)x-block-poly(benzyl methacrylate)y diblock copolymer nano-objects with differing dimensions and morphologies is prepared by polymerization-induced self-assembly (PISA) mediated by reversible addition-fragmentation chain transfer polymerization (RAFT). Such copolymer nano-objects and ultrasmall calcium phosphate oligomers (CPOs) are used as dual fillers for the preparation of polymer-inorganic composite films using sodium carboxymethyl cellulose (CMC) as a matrix. Impressively, the strength and toughness of such composite films are substantially reinforced as high as up to 202.5 ± 14.8 MPa and 62.3 ± 7.9 MJ m-3, respectively. Owing to the intimate interaction between the polymer-inorganic interphases at multiple scales, their mechanical performances are superior to most conventional polymer films and other nanocomposite films. This study demonstrates the combination of polymeric fillers and inorganic fillers to reinforce the mechanical properties of the resultant composite films, providing new insights into the design rules for the construction of novel hybrid films with excellent mechanical performances.

Organic-Inorganic Copolymerization Induced Oriented Crystallization for Robust Lightweight Porous Composite

Porous composites are important in engineering fields for their lightweight, thermal insulation, and mechanical properties. However, increased porosity commonly decreases the robustness, making a trade-off between mechanics and weight. Optimizing the strength of solid structure is a promising way to co-enhance the robustness and lightweight properties. Here, acrylamide and calcium phosphate ionic oligomers are copolymerized, revealing a pre-interaction of these precursors induced oriented crystallization of inorganic nanostructures during the linear polymerization of acrylamide, leading to the spontaneous formation of a bone-like nanostructure. The resulting solid phase shows enhanced mechanics, surpassing most biological materials. The bone-like nanostructure remains intact despite the introduction of porous structures at higher levels, resulting in a porous composite (P-APC) with high strength (yield strength of 10.5 MPa) and lightweight properties (density below 0.22 g cm-3). Notably, the density-strength property surpasses most reported porous materials. Additionally, P-APC shows ultralow thermal conductivity (45 mW m-1 k-1) due to its porous structure, making its strength and thermal insulation superior to many reported materials. This work provides a robust, lightweight, and thermal insulating composite for practical application. It emphasizes the advantage of prefunctionalization of ionic oligomers for organic-inorganic copolymerization in creating oriented nanostructure with toughened mechanics, offering an alternative strategy to produce robust lightweight materials.

Sub-1 nm Materials Chemistry: Challenges and Prospects

Subnanometer materials (SNMs) refer to nanomaterials with a feature size close to 1 nm, similar to the diameter of a single polymer, DNA strand, and a single cluster/unit cell. The growth and assembly of subnanometer building blocks can be controlled by interactions at atomic levels, representing the limit for the precise manipulation of materials. The size, geometry, and flexibility of 1D SNMs inorganic backbones are similar to the polymer chains, bringing excellent gelability, adhesiveness, and processability different from inorganic nanocrystals. The ultrahigh surface atom ratio of SNMs results in significantly increased surface energy, leading to significant rearrangement of surface atoms. Unconventional phases, immiscible metal alloys, and high entropy materials with few atomic layers can be stabilized, and the spontaneous twisting of SNMs may induce the intrinsic structural chirality. Electron delocalization may also emerge at the subnanoscale, giving rise to the significantly enhanced catalytic activity. In this perspective, we summarized recent progress on SNMs, including their synthesis, polymer-like properties, metastable phases, structural chirality, and catalytic properties, toward energy conversion. As a critical size region in nanoscience, the development of functional SNMs may fuse the boundary of inorganic materials and polymers and conduce to the precise manufacturing of materials at atomic levels.

An organic/inorganic hybrid soft material for supramolecular adhesion

Thioctic acid (TA) has been widely used to construct soft materials via supramolecular copolymerization with organic chemicals. In this study, TA and the inorganic compound MoS2 are used to fabricate poly[TA-MoS2] via dynamic covalent and supramolecular interactions. Poly[TA-MoS2] exhibits good and long-lasting adhesion performance on various artificial surfaces, with an adhesion strength up to 3.72 MPa (15 days). Further, it exhibits tough adhesion effects in an aqueous environment. Moreover, poly[TA-MoS2] displays good thermal processing behavior, thus enabling its molding through 3D printing.

Wearable and Recyclable Water-Toleration Sensor Derived from Lipoic Acid

Flexible wearable sensors recently have made significant progress in human motion detection and health monitoring. However, most sensors still face challenges in terms of single detection targets, single application environments, and non-recyclability. Lipoic acid (LA) shows a great application prospect in soft materials due to its unique properties. Herein, ionic conducting elastomers (ICEs) based on polymerizable deep eutectic solvents consisting of LA and choline chloride are prepared. In addition to the good mechanical strength, high transparency, ionic conductivity, and self-healing efficiency, the ICEs exhibit swelling-strengthening behavior and enhanced adhesion strength in underwater environments due to the moisture-induced association of poly(LA) hydrophobic chains, thus making it possible for underwater sensing applications, such as underwater communication. As a strain sensor, it exhibits highly sensitive strain response with repeatability and durability, enabling the monitoring of both large and fine human motions, including joint movements, facial expressions, and pulse waves. Furthermore, due to the enhancement of ion mobility at higher temperatures, it also possesses excellent temperature-sensing performance. Notably, the ICEs can be fully recycled and reused as a new strain/temperature sensor through heating. This study provides a novel strategy for enhancing the mechanical strength of poly(LA) and the fabrication of multifunctional sensors.

Biological applications of lipoic acid-based polymers: an old material with new promise

Lipoic acid (LA) is a versatile antioxidant that has been used in the treatment of various oxidation-reduction diseases over the past 70 years. Owing to its large five-membered ring tension, the dynamic disulfide bond of LA is highly active, enabling the formation of poly(lipoic acid) (PLA) via ring-opening polymerization (ROP). Herein, we first summarize disulfide-mediated ROP polymerization strategies, providing basic routes for designing and preparing PLA-based materials. PLA, as a biologically derived, low toxic, and easily modified material, possesses dynamic disulfide bonds and universal non-covalent carboxyl groups. We also shed light on the biomedical applications of PLA-based materials based on their biological and structural features and further divide recent works into six categories: antibacterial, anti-inflammation, anticancer, adhesive, flexible electronics, and 3D-printed tissue scaffolds. Finally, the challenges and future prospects associated with the biomedical applications of PLA are discussed.

Construction of Mineralization Nanostructures in Polymers for Mechanical Enhancement and Functionalization

Mineralization capable of growing inorganic nanostructures efficiently, orderly, and spontaneously shows great potential for application in the construction of high-performance organic-inorganic composites. As a thermodynamically spontaneous solid-phase crystallization reaction involving dual organic and inorganic components, mineralization allows for the self-assembly of sophisticated and exclusive nanostructures within a polymer matrix. It results in a diversity of functions such as enhanced strength, toughness, electrical conductivity, selective permeability, and biocompatibility. While there are previous reviews discussing the progress of mineralization reactions, many of them overlook the significant benefits of interfacial regulation and functionalization that come from the incorporation of mineralized structures into polymers. Focusing on different means of assembly of mineralized nanostructures in polymer, the work analyzes their design principles and implementation strategies. Then, their different advantages and disadvantages are analyzed by combining nanostructures with organic substrates as well as involving the basis of different functionalizations. It is anticipated to provide insights and guidance for the future development of mineralized polymer composites and their application designs.

Luminescent Supramolecular Ionic Frameworks based on Organic Fluorescent Polycations and Polyanionic Phosphorescent Metal Clusters

Emissive ionic supramolecular frameworks are designed by associating tetraphenylethylene-based tetra-cationic units and di-anionic molybdenum or tetra-anionic rhenium octahedral clusters. Obtained structures were characterized by single-crystal X-ray diffraction. The emission properties of the hybrids were investigated as dry powders or in various solvents by one photon and two photon absorption leading to a O2 concentration dependent luminescence color for the Mo based hybrid.

A Tough Monolithic-Integrated Triboelectric Bioplastic Enabled by Dynamic Covalent Chemistry

Electronic waste is a growing threat to the global environment and human health, raising particular concerns. Triboelectric devices synthesized from sustainable and degradable materials are a promising electronic alternative, but the mechanical mismatch at the interface between the polymer substrate and the electrodes remains unresolved in practical applications. This study uses the sulfhydryl silanization reaction and the chemical selectivity and site specificity of the thiol-disulfide exchange reaction in dynamic covalent chemistry to prepare a tough monolithic-integrated triboelectric bioplastic. The stress is dissipated by covalent bond adaptation to the interface interaction, which makes the polymer dielectric layer to the conductive layer have a good interface adhesion effect (220.55 kPa). The interfacial interlocking of the polymer substrate with the conductive layer gives the triboelectric bioplastic excellent tensile strength (87.4 MPa) and fracture toughness (33.3 MJ m-3). Even when subjected to a tension force of 10 000 times its weight, it still maintains a stable triboelectric output with no visible cracks. This study provides new insights into the design of reliable and environmentally friendly self-powered devices, which is significant for the development of flexible wearable electronics.

A supramolecular approach for converting renewable biomass into functional materials

The rational transformation and utilization of biomass have attracted increasing attention because of its high importance in sustainable development and green economy. In this study, we used a supramolecular approach to convert biomass into functional materials. Six biomass raw materials with distinct chemical structures and physical properties were copolymerized with thioctic acid (TA) to afford poly[TA-biomass]s. The solvent-free copolymerization leads to the convenient and quantitative fabrication of biomass-based versatile materials. The non-covalent bonding and reversible solid-liquid transitions in poly[TA-biomass]s endow them with diversified features, including thermal processability, 3D printing, wet and dry adhesion, recyclability, impact resistance, and antimicrobial activity. Benefiting from their good biocompatibility and nontoxicity, these biomass-based materials are promising candidates for biological applications.

From salt water to bioceramics: Mimic nature through pressure-controlled hydration and crystallization

Modern synthetic technology generally invokes high temperatures to control the hydration level of ceramics, but even the state-of-the-art technology can still only control the overall hydration content. Magically, natural organisms can produce bioceramics with tailorable hydration profiles and crystallization traits solely from amorphous precursors under physiological conditions. To mimic the biomineralization tactic, here, we report pressure-controlled hydration and crystallization in fabricated ceramics, solely from the amorphous precursors of purely inorganic gels (PIGs) synthesized from biocompatible aqueous solutions with most common ions in organisms (Ca2+, Mg2+, CO32-, and PO43-). Transparent ceramic tablets are directly produced by compressing the PIGs under mild pressure, while the pressure regulates the hydration characteristics and the subsequent crystallization behaviors of the synthesized ceramics. Among the various hydration species, the moderately bound and ordered water appears to be a key in regulating the crystallization rate. This nature-inspired study offers deeper insights into the magic behind biomineralization.

Bioinspired Organic Porous Coupling Agent for Enhancement of Nanoparticle Dispersion and Interfacial Strength

Composite materials have significantly advanced with the integration of inorganic nanoparticles as fillers in polymers. Achieving fine dispersion of these nanoparticles within the composites, however, remains a challenge. This study presents a novel solution inspired by the natural structure of Xanthium. We have developed a polymer of intrinsic microporosity (PIM)-based porous coupling agent, named PCA. PCA's rigid backbone structure enhances interfacial interactions through a unique intermolecular interlocking mechanism. This approach notably improves the dispersion of SiO2 nanoparticles in various organic solvents and low-polarity polymers. Significantly, PCA-modified SiO2 nanoparticles embedded in polyisoprene rubber showed enhanced mechanical properties. The Young's modulus increases to 30.7 MPa, compared to 5.4 MPa in hexadecyltrimethoxysilane-modified nanoparticles. Further analysis shows that PCA-modified composites not only become stiffer but also gain strength and ductility. This research demonstrates a novel biomimetic strategy for enhancing interfacial interactions in composites, potentially leading to stronger, more versatile composite materials.

Controlled and Regioselective Ring-Opening Polymerization for Poly(disulfide)s by Anion-Binding Catalysis

Poly(disulfide)s are an emerging class of sulfur-containing polymers with applications in medicine, energy, and functional materials. However, the constituent dynamic covalent S-S bond is highly reactive in the presence of the sulfide (RS-) anion, imposing a persistent challenge to control the polymerization. Here, we report an anion-binding approach to arrest the high reactivity of the RS- chain end to control the synthesis of linear poly(disulfide)s, realizing a rapid, living ring-opening polymerization of 1,2-dithiolanes with narrow dispersity and high regioselectivity (Mw/Mn ∼ 1.1, Ps ∼ 0.85). Mechanistic studies support the formation of a thiourea-base-sulfide ternary complex as the catalytically active species during the chain propagation. Theoretical analyses reveal a synergistic catalytic model where the catalyst preorganizes the protonated base and anionic chain end to establish spatial confinement over the bound monomer, effecting the observed regioselectivity. The catalytic system is amenable to monomers with various functional groups, and semicrystalline polymers are also obtained from lipoic acid derivatives by enhancing the regioselectivity.

Bi2O3/Gd2O3 Meta-Aerogel with Leaf-Inspired Nanotrap Array Enables Efficient X-Ray Absorption

The increasing utilization of X-rays has generated a growing need for efficient shielding materials. However, the existing Pb-based materials suffer from a narrow X-ray absorbing range, high weight, and rigidity. Inspired by the natural leaf, which can efficiently absorb light through chlorophyll and carotenoids in confined cells, we engineer ultralight and superelastic nanofibrous Bi2O3/Gd2O3 meta-aerogels (BGAs) with X-ray nanotrap arrays by manipulating the 3D confined assembly of 1D Bi2O3 and Gd2O3 nanofibers. The BGAs can synergistically absorb X-ray photons from complementary energy ranges into the nanotraps and induce cyclic collisions with Bi2O3 and Gd2O3 nanofibers, maximizing the effective X-ray attenuation. The meta-aerogel exhibits the integrated performance of efficient X-ray shielding efficiency (60-83%, 16-90 keV), ultralow density (10 mg cm-3), and superelasticity. The production of these meta-aerogels presents an avenue for the development of next-generation X-ray protective materials and the resolution of X-ray imaging systems.

Multifunctionality in Nature: Structure-Function Relationships in Biological Materials

Modern material design aims to achieve multifunctionality through integrating structures in a diverse range, resulting in simple materials with embedded functions. Biological materials and organisms are typical examples of this concept, where complex functionalities are achieved through a limited material base. This review highlights the multiscale structural and functional integration of representative natural organisms and materials, as well as biomimetic examples. The impact, wear, and crush resistance properties exhibited by mantis shrimp and ironclad beetle during predation or resistance offer valuable inspiration for the development of structural materials in the aerospace field. Investigating cyanobacteria that thrive in extreme environments can contribute to developing living materials that can serve in places like Mars. The exploration of shape memory and the self-repairing properties of spider silk and mussels, as well as the investigation of sensing-actuating and sensing-camouflage mechanisms in Banksias, chameleons, and moths, holds significant potential for the optimization of soft robot designs. Furthermore, a deeper understanding of mussel and gecko adhesion mechanisms can have a profound impact on medical fields, including tissue engineering and drug delivery. In conclusion, the integration of structure and function is crucial for driving innovations and breakthroughs in modern engineering materials and their applications. The gaps between current biomimetic designs and natural organisms are also discussed.