A facile cross-linking strategy of using small molecules as physcial crosslinkers to facilitate recyclable polybutadiene (PB) elastomer with excellent toughness and stretchability is demonstrated. Carboxylic acid groups were incorporated along the PB backbone via thiol-ene reaction, and then the polymer can be cross-linked by ionic hydrogen bonds between the carboxylic acid groups from PB and the amine groups of the cross-linkers. The ionic hydrogen bonds can dynamiclly break and reconstruct upon deformation, thus endowing the resultant polymer with not only high toughness and stretchability (∼1800%), but also good self-recovery and enhanced damping properties. Remarkably, the dynamically cross-linked PB elastomer can be thermally recycled owing to the thermal reversibility of the ionic hydrogen bonds and the mechanical properties can be largely recovered after reprocessing. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1357-1366

A facile method of fabricating metal oxide hollow spheres using polydopamine (PDA) nanoparticles as active templates is reported. Monodisperse PDA nanoparticles were prepared by the polymerization of dopamine in Tris buffer solution containing various amounts of poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO-PPO-PEO). The diameter of the resultant PDA nanoparticles decreased from about 180 to 80 nm with an increase of PEO-PPO-PEO concentration from 0 to 1.25 mg mL⁻¹. The active groups of PDA and also the PEO-PPO-PEO adsorbed on the PDA spheres can chelate with various metal ions. It was found that when PDA spheres with diameter below 100 nm were used as templates, diverse metal oxide hollow spheres like CeO₂, NiO and Cr₂O₃ could be obtained after calcination, demonstrating the diversity of this method for fabricating various metal oxide hollow spheres. © 2015 Society of Chemical Industry

The surprising properties of biomaterials are the results of billions of years of evolution. Generally, biomaterials are assembled under mild conditions with very limited supply of constituents available for living organism, and their amazing properties largely result from the sophisticated hierarchical structures. Following the biomimetic principles to prepare manmade materials has drawn great research interests in materials science and engineering. In this review, we summarize the recent progress in fabricating bioinspired materials with the emphasis on mimicking the structure from one to three dimensions. Selected examples are described with a focus on the relationship between the structural characters and the corresponding functions. For one-dimensional materials, spider fibers, polar bear hair, multichannel plant roots and so on have been involved. Natural structure color and color shifting surfaces, and the antifouling, antireflective coatings of biomaterials are chosen as the typical examples of the two-dimensional biomimicking. The outstanding protection performance, and the stimuli responsive and self-healing functions of biomaterials based on the sophisticated hierarchical bulk structures are the emphases of the three-dimensional mimicking. Finally, a summary and outlook are given.