The applications of hydrogels are severely limited by their weak mechanical properties. Despite recent significant progress in fabricating tough hydrogels, it is still a challenge to realize high stretchability, toughness, and recoverability at the same time in a hydrogel. Herein, we develop a novel class of dual physically cross-linked (DPC) hydrogels, which are triggered by clay nanosheets and iron ions (Fe 3+ ) as cross-linkers. First, clay nanosheets induce the formation of the first cross-linking points through the interaction of hydrogen bonds with poly(acrylamide-co-acrylic acid) (PAm-co-Ac) chains. Then the secondary cross-linking points are introduced by ionic coordinates between Fe 3+ and −COO− groups of PAm-co-Ac polymer chains. The mechanical properties of DPC hydrogels can be tuned readily by varying preparation parameters such as clay concentration, Fe 3+ concentration, and molar ratio of Ac/Am. More importantly, the optimal DPC hydrogels possess high tensile strength (ca. 3.5 MPa), large elongation (ca. 21 times), remarkable toughness (ca. 49 MJ m −3 ), and good self-recoverability (ca. 65% toughness recovery within 4 h without any external stimuli). Thus, this work provides a promising strategy for the fabrication of novel tough hydrogel containing a dual physical cross-linked network.

In this work, robust nanocarbons, including graphite (G), carbon nanotube (CNT), reduced graphene oxide (rGO), carbon black (CB), and acetylene black (AB), have been successfully coupled into the interfaces between g-C3N4 and NiS using a facile precipitation method. The results demonstrated that nanocarbons played trifunctional roles in boosting the photocatalytic H2 evolution over g-C3N4, which can not only act as effective H2-evolution co-catalysts but can also serve as conductive electron bridges to collect photogenerated electrons and boost the H2-evolution kinetics over the NiS co-catalysts. More interestingly, the nanocarbons can also result in the downshift of valence band of g-C3N4, thus facilitating the fast oxidation of triethanolamine and charge-carrier separation. Particularly, in all five ternary multiheterostructured systems, the g-C3N4-0.5%CB-1.0%NiS (weight ratio) and g-C3N4-0.5%AB-1.0%NiS photocatalysts exhibited the highest H2-evolution rates of 366.4 and 297.7 μmol g–1 h–1, which are 3.17 and 2.57 times higher than that of g-C3N4-1.0%NiS, respectively. Apparently, the significantly enhanced H2-evolution activity of multiheterostructured g-C3N4/carbon/NiS composite photocatalysts can be mainly ascribed to the trifunctional nanocarbons, which serve as the conductive electron bridges rather than the general co-catalysts. More importantly, it is revealed that the amorphous carbons with higher electrical conductivity and weaker electrocatalytic H2-evolution activity are more suitable interfacial bridges between g-C3N4 and NiS co-catalysts for maximizing the H2 generation. This work may give a new mechanistic insight into the development of multiheterostructured g-C3N4-based composite photocatalysts using the combination of trifunctional nanocarbon bridges and earth-abundant co-catalysts/semiconductors for various photocatalytic applications.

A series of shape memory polyurethanes (SMPUs) was prepared from polycaprolactone diol (PCL) 4000, 1,4‐butanediol (BDO), dimethylol propionic acid (DMPA), triethylamine, and 4, 4′‐diphenylmethane diisocyanate (MDI), to which excess MDI or glycerin were added to obtain crosslinked shape memory polyurethanes. Their mechanical, thermomechanical, thermal and shape memory properties were investigated by using differential scanning calorimetry (DSC), Fourier‐transform (FT‐IR) spectroscopy, dynamic mechanical analysis (DMA) and tensile testing. The results showed that crosslinked SMPUs have better thermal and thermomechanical properties than those prepared from linear polyurethanes and display good shape memory effects. Copyright © 2005 Society of Chemical Industry

Strongly coupled and porous MoS2–CNT with leaves-and-branch structure shows a remarkably improved electrocatalytic activity towards hydrogen evolution reaction.

A solvent-free and scalable method was developed for the preparation of soybean-oil-based polyols by a thiol–ene photo-click reaction with a homemade photochemical reactor. The effect of reaction parameters, including photoinitiators, reaction time, molar ratios of thiols to carbon–carbon double bonds, and power of the mercury lamp, on the structures of the resulting polyols was investigated. The mechanism of the thiol–ene photo-click reaction was also discussed. On the basis of these novel polyols, several polyurethanes were prepared using different diisocyanates (aliphatic, cycloaliphatic, and aromatic isocyanate) and characterized. The resulting polyurethane films possess good performance, including the highest glass transition temperature of 41.3 °C, tensile strength of 15.7 MPa, and elongation at break of 471.0%.

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Enhanced visible-light photocatalytic H2 evolution over g-C3N4 nanosheets modified by earth-abundant WC nanoparticles as an active noble-metal-free co-catalyst.

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