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  1. Abstract

    A facile, one‐step, and single‐component fabrication of superhydrophobic and superoleophilic coating by electropolymerization of polythiophene on a stainless steel mesh is presented. The resulting coating has low surface energy and shows surface morphology bearing both micro‐ and nano‐features without the need to add nanofillers, or pretreatment of the substrate to make it rough. The polythiophene coating also shows reversible wetting property (superhydrophobic to superhydrophilic, and vice versa) by electrochemical doping and dedoping. The coated mesh is shown to repel water of different pH (1, 7, and 14) and salt content. On the other hand, oil such as dichloromethane, gasoline, kerosene, dodecane, and crude oil can easily pass through the mesh. Therefore, the coated mesh is an excellent material for the separation of oil and water.

     
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  2. Abstract

    A mechanically robust, ultraelastic foam with controlled multiscale architectures and tunable mechanical/conductive performance is fabricated via 3D printing. Hierarchical porosity, including both macro‐ and microscaled pores, are produced by the combination of direct ink writing (DIW), acid etching, and phase inversion. The thixotropic inks in DIW are formulated by a simple one‐pot process to disperse duo nanoparticles (nanoclay and silica nanoparticles) in a polyurethane suspension. The resulting lightweight foam exhibits tailorable mechanical strength, unprecedented elasticity (standing over 1000 compression cycles), and remarkable robustness (rapidly and fully recover after a load more than 20 000 times of its own weight). Surface coating of carbon nanotubes yields a conductive elastic foam that can be used as piezoresistivity sensor with high sensitivity. For the first time, this strategy achieves 3D printing of elastic foam with controlled multilevel 3D structures and mechanical/conductive properties. Moreover, the facile ink preparation method can be utilized to fabricate foams of various materials with desirable performance via 3D printing.

     
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  3. Abstract

    Polymer‐grafted inorganic particles (PGIPs) are attractive building blocks for numerous chemical and material applications. Surface‐initiated controlled radical polymerization (SI‐CRP) is the most feasible method to fabricate PGIPs. However, a conventional in‐batch reaction still suffers from several disadvantages, including time‐consuming purification processes, low grafting efficiency, and possible gelation problems. Herein, a facile method is demonstrated to synthesize block copolymer–grafted inorganic particles, that is, poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMEMA)‐b‐poly(N‐isopropylacrylamide) (PNIPAM)–grafted silica micro‐particles using continuous flow chemistry in an environmentally friendly aqueous media. Immobilizing the chain transfer agent and subsequent SI‐CRP can be accomplished sequentially in a continuous flow system, avoiding multi‐step purification processes in between. The chain length (MW) of the grafted polymers is tunable by adjusting the flow time or monomer concentration, and the narrower molar mass dispersity (Р< 1.4) of the grafted polymers reveals the uniform polymer chains on the particles. Moreover, compared with the in‐batch reaction at the same condition, the continuous system also suppresses possible gelation problems.

     
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  4. Abstract

    Highly elastic silicone foams, especially those with tunable properties and multifunctionality, are of great interest in numerous fields. However, the liquid nature of silicone precursors and the complicated foaming process hinder the realization of its three‐dimensional (3D) printability. Herein, a series of silicone foams with outstanding performance with regards to elasticity, wetting and sensing properties, multifunctionality, and tunability is generated by direct ink writing. Viscoelastic inks are achieved from direct dispersion of sodium chloride in a unique silicone precursor solution. The 3D‐architectured silicone rubber exhibits open‐celled trimodal porosity, which offers ultraelasticity with hyper compressibility/cycling endurance (near‐zero stress/strain loss under 90% compression or 1000 compression cycles), excellent stretchability (210% strain), and superhydrophobicity. The resulting foam is demonstrated to be multifunctional, such that it can work as an oil sorbent with super capacity (1320%) and customizable soft sensor after absorption of carbon nanotubes on the foam surface. The strategy enables tunability of mechanical strength, elasticity, stretchability, and absorbing capacity, while printing different materials together offers property gradients as an extra dimension of tunability. The first 3D printed silicone foam, which serves an important step toward its application expansion, is achieved.

     
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