Spider silk is one of the most robust natural materials, which has extremely high strength in combination with great toughness and good elasticity. Inspired by spider silk but beyond it, a healable ...and recyclable supramolecular elastomer, possessing superhigh true stress at break (1.21 GPa) and ultrahigh toughness (390.2 MJ m−3), which are, respectively, comparable to and ≈2.4 times higher than those of typical spider silk, is developed. The elastomer has the highest tensile strength (ultimate engineering stress, 75.6 MPa) ever recorded for polymeric elastomers, rendering it the strongest and toughest healable elastomer thus far. The hyper‐robust elastomer exhibits superb crack tolerance with unprecedentedly high fracture energy (215.2 kJ m−2) that even exceeds that of metals and alloys, and superhigh elastic restorability allowing dimensional recovery from elongation over 12 times. These extraordinary mechanical performances mainly originate from the meticulously engineered hydrogen‐bonding segments, consisting of multiple acylsemicarbazide and urethane moieties linked with flexible alicyclic hexatomic spacers. Such hydrogen‐bonding segments, incorporated between extensible polymer chains, aggregate to form geometrically confined hydrogen‐bond arrays resembling those in spider silk. The hydrogen‐bond arrays act as firm but reversible crosslinks and sacrificial bonds for enormous energy dissipation, conferring exceptional mechanical robustness, healability, and recyclability on the elastomer.
Healable and recyclable elastomers with superhigh strength (tensile strength ≈ 75.6 MPa, true stress at break ≈ 1.21 GPa) and ultrahigh toughness (≈390.2 MJ m−3) are reported. The elastomer has unprecedented crack tolerance with fracture energy of 215.2 kJ m−2 that even exceeds that of metals and alloys. The elastomer exhibits superhigh elastic restorability allowing dimensional recovery from elongation over 12 times.
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation–anion moieties ...and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
Plasma membrane rupture often leads to cell damage, especially when there is a lack of membrane repair proteins near the wounds due to genetic mutations in organisms. To efficiently promote the ...repair of the injured lipid membrane, nanomedicines may act as a promising alternative to membrane repair proteins, but the related research is still in its infancy. Herein, using dissipative particle dynamics simulations, we designed a class of Janus polymer-grafted nanoparticles (PGNPs) that can mimic the function of membrane repair proteins. The Janus PGNPs comprise both hydrophobic and hydrophilic polymer chains grafted on nanoparticles (NPs). We track the dynamic process of the adsorption of Janus PGNPs at the damaged site in the lipid membrane and systematically assess the driving forces for this process. Our results reveal that tuning the length of the grafted polymer chains and the surface polarity of the NPs can efficiently enhance the adsorption of Janus PGNPs at the site of the damaged membrane to reduce membrane stress. After repair, the adsorbed Janus PGNPs can be successfully detached from the membrane, leaving the membrane untouched. These results provide valuable guidelines for designing advanced nanomaterials for the repair of damaged lipid membranes.
Nanoporous structures constructed by small molecular components exhibited vigorous materials potentials. While maintianing uniform porosity and functional properties, more applicable processing ...methods for the solid powders need to be considered and the improvement of binding interactions represents a preferable approach for structural flexibility. Here, by combining ionic interaction and host-guest inclusion, we constructed flexible supramolecular frameworks composing of inorganic polyanionic clusters, cationic organic hosts, and a bridging guest. The formed layer framework structure assemblies grew into nano-fibers and then supramolecular gels, donating highly convenient processability to porous materials. A simple spin-coating generated a new type of liquid separation membranes which showed structural stability for many liquids. The surface properties can be facilely modulated via filling a joystick liquid and then a hydrophilic/hydrophobic liquid into the porous frameworks, providing in-situ consecutive switchings for cutting liquids. This strategy extends the potential of flexible supramolecular frameworks for responsive materials in the laboratory and in industry.
The collapse or folding of an individual polymer chain into a nanoscale particle gives rise to single‐chain nanoparticles (SCNPs), which share a soft nature with biological protein particles. The ...precise control of their properties, including morphology, internal structure, size, and deformability, are a long‐standing and challenging pursuit. Herein, a new strategy based on amphiphilic alternating copolymers for producing SCNPs with ultrasmall size and uniform structure is presented. SCNPs are obtained by folding the designed alternating copolymer in N,N‐dimethylformamide (DMF) and fixing it through a photocatalyzed cycloaddition reaction of anthracene units. Molecular dynamics simulation confirms the solvophilic outer corona and solvophobic inner core structure of SCNPs. Furthermore, by adjusting the length of PEG units, precise control over the mean size of SCNPs is achieved within the range of 2.8 to 3.9 nm. These findings highlight a new synthetic strategy that enables enhanced control over morphology and internal structure while achieving ultrasmall and uniform size for SCNPs.
In this study, a novel approach based on amphiphilic alternating copolymers for the synthesis of small‐sized and compact single‐chain nanoparticles (SCNPs) structures is proposed. Precise control over the average size of SCNPs is achieved within the range of 2.8 to 3.9 nm. These findings underscore a new synthetic strategy that enables enhanced manipulation of morphology and internal architecture.
Since the discovery of amorphous red phosphorus (a‐red P) in 1847, many possible structures have been proposed. However, the exact molecular structure has not yet been determined because of its ...amorphous nature. Herein several methods are used to investigate basic properties of a‐red P. Data from scanning tunneling microscopy (STM) and gel permeation chromatography (GPC) confirm that a‐red P is a linear inorganic polymer with a broad molecular weight distribution. The theoretical single‐molecule elasticities of the possible a‐red P structures are obtained by quantum mechanical (QM) calculations. The experimental single‐molecule elasticity of a‐red P measured by single‐molecule AFM matches with the theoretical result of the zig‐zag ladder structure, indicating that a‐red P may adopt this structure. Although this conclusion needs further validation, this fundamental study represents progress towards solving the structure of a‐red P. It is expected that the strategy utilized in this work can be applied to study other inorganic polymers.
Zig‐zag: Although amorphous red phosphorus (a‐red P) was discovered for more than 170 years, its exact molecular structure is unknown because of its amorphous nature. Results from single‐molecule AFM, quantum mechanical calculations, and scanning tunneling microscopy suggest that a‐red P may adopt a zig‐zag ladder structure (2 in Scheme).
A viologen-based porous organic polymer, POP-V-VI, was designed and synthesized by a facile nucleophilic substitution between cyanuric chloride and 1,2-bis(4-pyridinium) ethylene. Together with the ...reported POP-V-BPY with a similar structure, these viologen-based porous organic polymers bear high charge density, phenyl ring and nitrogenous affinity sites, which endow them with excellent iodine vapor uptake capacity (4860 mg g
−1
for POP-V-VI and 4200 mg g
−1
for POP-V-BPY) and remarkably high adsorption capacity for pyridine (4470 mg g
−1
for POP-V-VI and 8880 mg g
−1
for POP-V-BPY) and other aliphatic amines. POP-V-VI and POP-V-BPY could be efficiently recycled and reused three times without significant loss of iodine vapor uptake. All these results demonstrate that POP-V-VI and POP-V-BPY are promising adsorbents for practical applications in portable devices such as gas masks.
Viologen-based porous organic polymers as highly efficient and reversible adsorbents for iodine and amines.
Fabricating polymer electrolyte membranes (PEMs) simultaneously with high ion conductivity and selectivity has always been an ultimate goal in many membrane‐integrated systems for energy conversion ...and storage. Constructing broader ion‐conducting channels usually enables high‐efficient ion conductivity while often bringing increased crossover of other ions or molecules simultaneously, resulting in decreased selectivity. Here, the ultra‐small carbon dots (CDs) with the selective barriers are self‐assembled within proton‐conducting channels of PEMs through electrostatic interaction to enhance the proton conductivity and selectivity simultaneously. The functional CDs regulate the nanophase separation of PEMs and optimize the hydration proton network enabling higher‐efficient proton transport. Meanwhile, the CDs within proton‐conducting channels prevent fuel from permeating selectively due to their repelling and spatial hindrance against fuel molecules, resulting in highly enhanced selectivity. Benefiting from the improved conductivity and selectivity, the open‐circuit voltage and maximum power density of the direct methanol fuel cell (DMFC) equipped with the hybrid membranes raised by 23% and 93%, respectively. This work brings new insight to optimize polymer membranes for efficient and selective transport of ions or small molecules, solving the trade‐off of conductivity and selectivity.
The ultra‐small size carbon dots (CDs) with the selective barrier function are self‐assembled within proton transport channels through electrostatic interaction to realize a design of nano‐scale “screener in channels”, which enhance the conductivity and selectivity of polymer electrolyte membranes (PEMs) simultaneously for high‐performance fuel cell (FC).
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