The design and synthesis of supramolecular self‐healing polymers with high healing efficiency and excellent integrated mechanical properties is challenging due to conflicting attributes of dynamic self‐healing and mechanical properties. Herein, this study introduces a design concept, that is, “dynamic hard domains,” to balance self‐healing performance, mechanical strength, elastic recovery, and at the same time obtain extreme toughness. The essential features of the dynamic hard domains include: (i) a noncrystallized and loose structure, (ii) low binding energy and high mobility, and (iii) sequential dissociation and rapid rearrangement. Based on this strategy, a simple one‐step polycondensation route is reported to synthesize a transparent polyurethane‐urea supramolecular elastomer (PPGTD‐IDA), which successfully combines decent mechanical strength, extreme toughness, outstanding notch‐sensitiveness, self‐recoverability, and room‐temperature self‐healing. Upon rupture, the PPGTD‐IDA completely restores the mechanical properties within 48 h. Furthermore, the results demonstrate repeatable healing of mechanical properties and prominent antiaging healability. Taking advantages of merits of PPGTD‐IDA, it can be utilized for fabricating impact‐resistant materials for protection of aluminum alloys as well as stretchable and self‐healing conductors, which exhibits unique characteristics such as stable conductivity during stretching (even after healing or with notch), and automatic elimination of the notch during stretching/releasing cycles.
We designed and synthesized acolorless transparent glassy polyurethane assembled using low-molecular-weight oligomers carrying al arge number of loosely packed weak hydrogen bonds (H-bonds), which has ag lass transition temperature (T g)u pt o3 6.8 8 8Ca nd behaves unprecedentedly robust stiffness with at ensile Youngsm odulus of 1.56 AE 0.03 GPa. Fast room-temperature self-healing was observed in this polymer network:t he broken glassy polyurethane (GPU) specimen can recover to at ensile strength up 7.74 AE 0.76 MPaa fter healing for as little as 10 min, whichi s prominent compared to reported room-temperature self-healing polymers.T he high density of loose-packedh ydrogen bonds can reversibly dissociate/associate belowT g of GPU (that is secondary relaxation), which enables the reconfiguration of the damaged network in the fractured interfaces,despite the extremely slow diffusion dynamics of molecular chains under room temperature.T his GPU shows potential application as an optical lens.
Soft self-healing materials are compelling candidates for stretchable devices because of their excellent compliance, extensibility, and self-restorability. However, most existing soft self-healing polymers suffer from crack propagation and irreversible fatigue failure due to easy breakage of their dynamic amorphous, low-energy polymer networks. Herein, inspired by distinct structure-property relationship of biological tissues, a supramolecular interfacial assembly strategy of preparing soft self-healing composites with unprecedented crack propagation resistance is proposed by structurally engineering preferentially aligned lamellar structures within a dynamic and superstretchable poly(urea-ureathane) matrix (which is elongated to 24 750× its original length). Such a design affords a world-record fracture energy (501.6 kJ m −2 ), ultrahigh fatigue threshold (4064.1 J m −2 ), and outstanding elastic restorability (dimensional recovery from 13 times elongation), and preserving low modulus (1.2 MPa), high stretchability (3200%), and high room-temperature self-healing efficiency (97%). Thereby, the resultant composite represents the best of its kind and even surpasses most biological tissues. The lamellar 2D transition-metal carbide/carbonitride (MXene) structure also leads to a relatively high in-plane thermal conductivity, enabling composites as stretchable thermoconductive skins applied in joints of robotics to thermal dissipation. The present work illustrates a viable approach how autonomous self-healing, crack tolerance, and fatigue resistance can be merged in future material design.
The aim of this report was to refine the genotypes and phenotypes of chromodomain helicase DNA‐binding protein 2 (CHD2)‐related epilepsy. Seventeen patients with CHD2 mutations were enrolled. CHD2 mutations were identified by application of next‐generation sequencing of epilepsy or whole exome sequencing. Sixteen mutations were identified, among which 15 have not yet been reported. Thirteen mutations were de novo. Age at seizure onset ranged from 3 months to 10 years 5 months. Seizures observed were generalized tonic–clonic, myoclonic, atonic, atypical absence, focal, and myoclonic–atonic. Epileptic spasms occurred in two patients. Developmental disability was present in 14 patients. Autism features were observed in seven patients. Video electroencephalogram was abnormal in 15 patients. Five patients were diagnosed with non‐specific epileptic encephalopathy, two with epilepsy with myoclonic–atonic seizures, two with Lennox–Gastaut syndrome, two with febrile seizures plus, and one with West syndrome. Seizures were controlled in nine patients. Q1392TfsX17 may be a hot‐spot mutation of CHD2. West syndrome was observed as a new phenotype of CHD2 mutation. The severity of the phenotypes of CHD2 mutations ranged from mild febrile seizures to severe epileptic encephalopathy. What this paper adds Q1392TfsX17 maybe the hot‐spot mutation of CHD2. West syndrome could be a new phenotype of CHD2 mutation.
Energetic self-healing adhesives have a positive effect on the energy level, mechanical properties, and microcrack healing performance of energetic composite materials (ECMs). However, it is very challenging to design and...
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