A series of cobalt(II) dichloride complexes ligated by 2-[1-(2,4-dibenzhydryl-6-methylphenylimino) ethyl]-6-[1-(arylimino)ethyl]pyridines was synthesized and characterized by FT-IR spectroscopy and elemental analysis. The molecular structure of the representative complex Co4 (R1 = Me, R2 = Me) was confirmed as pseudo square-pyramidal geometry at cobalt by single-crystal X-ray diffraction. Upon treatment with the co-catalysts MAO or MMAO, all cobalt pre-catalysts exhibited high activities up to 1.81 × 107 g PE mol-1(Co) h-1 in ethylene polymerization, and produced polyethylene products with molecular weights in the tens of thousands and narrow molecular weight distributions. The influence of the reaction parameters and nature of the ligands on the catalytic behavior of the title cobalt complexes was investigated

Smart hydrogels with the capability of programmable shape memory have the potential to revolutionize medicine and soft robotics. Despite significant progress in designing hydrogels with ever more sophisticated shape memory...

No abstract

No abstract

Repeatable dual-encryption platforms, coupled with a strong protective capacity for stored information, are highly desirable for current data security but still a challenge to be realized. Herein, a new type of thermoset-based repeatable dual-encryption platform is designed to fulfill the challenge. Through introducing dynamic boroxine bonds and hydrogen bonds within the thermoset, self-healing, recyclability, and shape-memory properties can be achieved. Given the shape memory behavior of this thermoset, encryption data within complex 3D structures can be realized. Thus, shape recovery is inevitable for the decryption, providing strong protection for encrypted data. Furthermore, the encrypted data can be protected by showing misleading information before true information during the decryption process, which is caused by the different analogous "LEGO" assembly sequences of thermosets that induces different hydrophobic association interactions. The decrypted information can be erased by heating, realizing the repeatable encryption/ decryption. Additionally, the thermosets can be efficiently recycled. This strategy opens up a smart prospect for high level dual-encryption platform.

A well-defined shape memory network with high homogeneity was engineered via step-growth thiol-norbornene photopolymerization.

Development of shape memory polymer materials with integrated self-healing ability, shape memory property, and outstanding mechanical properties is a challenge. Herein, isophorone diisocyanate, polytetramethylene ether glycol, dimethylglyoxime, and glycerol have been used to preparation polyurethane by reacting at 80 C for 6 h. Then, graphene oxide (GO) was added and the reaction keep at 80 C for 4 h to obtain polyurethane/GO composite with selfhealing and shape memory properties. Scanning electron microscopy shows that the GO sheets were dispersed uniformly in the polyurethane matrix. The thermal stability was characterized by thermogravimetric analyses. The tensile test shows that the Young's modulus of the composites increases from 38.57 ± 4.35 MPa for pure polyurethane to 95.36 ± 10.35 MPa for the polyurethane composite with a GO content of 0.5 wt%, and the tensile strength increases from 6.28 ± 0.67 to 15.65 ± 1.54 MPa. The oxime carbamate bond and hydrogen bond endow the composite good self-healing property. The healing efficiency can reach 98.84%. In addition, the composite has excellent shape memory property, with a shape recovery ratio of 88.6% and a shape fixation ratio of 55.2%. This work provides a promising way to fabricate stimulusresponsive composite with versatile functions.

Wearable electronics based on stimuli-responsive hydrogels are promising in various applications such as soft robots, artificial skin, and health monitoring. Herein, a novel wearable and strain/thermal dual sensor is developed utilizing a nanocomposite hydrogel, which is prepared by incorporating allyl mercaptan (ALM) functionalized Au nanoparticles (Au@ALM) into poly(N-isopropylacrylamide-co-hydroxyethylmethacrylate)/poly(Nisopropylacrylamide) (P(NIPAM-co-HEMA)/PNIPAM) semi-interpenetrating hydrogel network. PNIPAM acts as the thermally responsive component. Semi-interpenetrating network and Au nanoparticles are introduced to enhance the mechanical properties of the hydrogel. Au nanoparticles also work as the electrically conductive component. Strain sensor and thermoreceptor are realized by using the mechanical stretchability and strainor temperature-dependent conductivity. The strain sensor exhibited excellent stability and repeatability in the strain range of 0-150%. Remarkably, the thermal sensor made of this hydrogel can monitor the ambient temperature from 0 to 70 °C. Therefore, an intelligent thermal switch is designed that can effectively protect electronic components by disconnecting high-temperature circuits. The nanocomposite hydrogel holds great potential in smart devices and flexible sensors.