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Nowadays, hydrogels as flexible materials have attracted considerable attention in frontier fields such as wearable electronic devices, soft actuators and robotics. However, water-based hydrogels inevitably freeze at subzero temperatures and suffer damage from contact with objects, which greatly reduce their service life and practical value. Herein, nanocomposite hydrogels with self-healing performance at subzero temperatures were proposed by introducing binary water-glycerol continuous phase and dual self-healing interactions. The binary solvents were emphasized in preventing the formation of ice crystals, enhancing flexible and self-healing abilities of hydrogels in subzero environment. Linseed oil as healing agent was effectively loaded in Pickering droplets by cellulose nanocrystals. Owing to non-covalent bonding and external healing agent, the obtained hydrogels showed improved mechanical properties and self-healing abilities. Particularly, after incorporating Pickering droplets, the rupture stress of nanocomposite hydrogels was 0.24 MPa, the rupture strain was 1900% and the healing efficiency could be up to 80.1% for 12 h at − 20 °C. Therefore, the obtained hydrogels with frost resistance, stretchability and self-healing properties should have broader potential applications, especially in subzero environment. [ABSTRACT FROM AUTHOR]

Recently years, hydrogels have received increased attention due to their promising applications in wound dressing, tissue engineering, biosensors and human-machine interfaces. However, designing hydrogels with good mechanical strength and self-healing ability remains a challenge. As a novel strategy, functional Janus nanosheets (JNs) were used as reinforcement to develop self-healing nanocomposite hydrogels. Herein, the silica Janus hollow spheres were prepared by a sol-gel process, modified with poly(2-(acryloyloxy)ethyl ferrocenecarboxylate)(PMAEFc)/polydopamine(PDA) to the internal/external surfaces and then crushed to fabricate the SiO 2 @PMAEFc/PDA JNs. The SiO 2 @PMAEFc/PDA JNs were then used as robust reinforcement to design self-healing nanocomposite hydrogels. Based on multiple effects of metal–coordination and host–guest interactions, the mechanical strengths and self-healing properties of hydrogels were both enhanced. Specially, after introducing JNs, the rupture stress of hydrogels increased from 1.27 MPa to 2.23 MPa, and the self-healing efficiency improved from 66.7% to 92.4%. These results demonstrate that JNs can be used as robust reinforcement to fabricate self-healing nanocomposite hydrogels, which enriches the design of self-healing hydrogels and broadens the application prospects of Janus nanomaterials. [Display omitted] • SiO2@PMAEFc JHSs were prepared by emulsion interface sol-gel process and radical polymerization. • SiO2@PMAEFc/PDA JHSs were obtained based on Mussel-Chemistry. • SiO2@PMAEFc/PDA JNH possessed outstanding self-healing properties and mechanical strength. • A simple preparation method of nanocomposite self-healing hydrogel was designed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Shewanella loihica PV-4 exhibited high performance in reducing CO 2 to formate. • A novel three-dimensional biological self-assembled cathode was constructed. • No involvement of electron mediators was found in whole cell catalysis. • Faraday efficiency of bioelectrosynthetic CO 2 -to-formate reached 99.95%. Bioelectrochemical CO 2 reduction (bio-CO 2 R) provides a sustainable and carbon neutral power-to-chemical route. Whole-cell electrosynthesis is one of the attractive strategies to realize CO 2 R due to its simple and low-cost superiorities. However, it is still challenging to overcome the sluggish transmembrane electron transfer of microorganisms without exogenously added mediators. Here, we described the fabrication of biohydrogel that contains bio-reduced graphene oxide (rGO) and living electroactive bacteria (EAB) for bio-CO 2 R. The EAB exhibited surprising ability to self-assemble biohydrogel that was further served as biocathode to drive CO 2 -to-formate electrosynthesis. With the close interaction between EAB and rGO nanosheets, the transmembrane electron transfer achieved at high Faradaic efficiency (∼99.5 %) and 46-fold increase of formate titer without exogenous mediator. This work provided the facile and practical approach to bridge the bacterial cell and electrode for efficient electron transfer and implied the new possibility to store the electric energy into chemicals with bio-CO 2 R. [ABSTRACT FROM AUTHOR]