A new self-repairing membrane for inflatable light weight structures such as rubber boats or Tensairity constructions is presented. Inspired by rapid self-sealing processes in plants, a thin soft cellular polyurethane...A new self-repairing membrane for inflatable light weight structures such as rubber boats or Tensairity constructions is presented. Inspired by rapid self-sealing processes in plants, a thin soft cellular polyurethane foam coating is applied on the inside of a fabric substrate, which closes the fissure if the membrane is punctured with a spike. Experimental tests are carried out with a purpose built setup by measuring the air mass flow through a leak in a damaged membrane sample. It is shown that the weight per unit area of the self-repairing foam as well as the curing of the two component PU-foam under an overpressure influence the repair efficiency. Curing the foam under overpressure affects the relative density as well as the microstructure of the foam coatings. Maximal median repair efficiencies of 0.999 have been obtained with 0.16 g.cm 2 foam cured at 1 bar overpressure. These results suggest that the bio-inspired technique has the potential to extend the functional integrity of injured inflatable structures dramatically.展开更多
Although lithium(Li)and sodium(Na)metals can be selected as the promising anode materials for next‐generation rechargeable batteries of high energy density,their practical applications are greatly restricted by the u...Although lithium(Li)and sodium(Na)metals can be selected as the promising anode materials for next‐generation rechargeable batteries of high energy density,their practical applications are greatly restricted by the uncontrollable dendrite growth.Herein,a platinum(Pt)–copper(Cu)alloycoated Cu foam(Pt–Cu foam)is prepared and then used as the substrate for Li and Na metal anodes.Owing to the ultrarough morphology with a threedimensional porous structure and the quite large surface area as well as lithiophilicity and sodiophilicity,both Li and Na dendrite growths are significantly suppressed on the substrate.Moreover,during Li plating,the lithiated Pt atoms can dissolve into Li phase,leaving a lot of microsized holes on the substrate.During Na plating,although the sodiated Pt atoms cannot dissolve into Na phase,the sodiation of Pt atoms elevates many microsized blocks above the current collector.Either the holes or the voids on the surface of Pt–Cu foam what can be extra place for deposited alkali metal,what effectively relaxes the internal stress caused by the volume exchange during Li and Na plating/stripping.Therefore,the symmetric batteries of Li@Pt–Cu foam and Na@Pt–Cu foam have both achieved long‐term cycling stability even at ultrahigh areal capacity at 20 mAh cm−2.展开更多
文摘A new self-repairing membrane for inflatable light weight structures such as rubber boats or Tensairity constructions is presented. Inspired by rapid self-sealing processes in plants, a thin soft cellular polyurethane foam coating is applied on the inside of a fabric substrate, which closes the fissure if the membrane is punctured with a spike. Experimental tests are carried out with a purpose built setup by measuring the air mass flow through a leak in a damaged membrane sample. It is shown that the weight per unit area of the self-repairing foam as well as the curing of the two component PU-foam under an overpressure influence the repair efficiency. Curing the foam under overpressure affects the relative density as well as the microstructure of the foam coatings. Maximal median repair efficiencies of 0.999 have been obtained with 0.16 g.cm 2 foam cured at 1 bar overpressure. These results suggest that the bio-inspired technique has the potential to extend the functional integrity of injured inflatable structures dramatically.
基金The authors acknowledge the support of the National Nature Science Foundation of China (21908124)Zhaoqing Xijiang Talent Program.
文摘Although lithium(Li)and sodium(Na)metals can be selected as the promising anode materials for next‐generation rechargeable batteries of high energy density,their practical applications are greatly restricted by the uncontrollable dendrite growth.Herein,a platinum(Pt)–copper(Cu)alloycoated Cu foam(Pt–Cu foam)is prepared and then used as the substrate for Li and Na metal anodes.Owing to the ultrarough morphology with a threedimensional porous structure and the quite large surface area as well as lithiophilicity and sodiophilicity,both Li and Na dendrite growths are significantly suppressed on the substrate.Moreover,during Li plating,the lithiated Pt atoms can dissolve into Li phase,leaving a lot of microsized holes on the substrate.During Na plating,although the sodiated Pt atoms cannot dissolve into Na phase,the sodiation of Pt atoms elevates many microsized blocks above the current collector.Either the holes or the voids on the surface of Pt–Cu foam what can be extra place for deposited alkali metal,what effectively relaxes the internal stress caused by the volume exchange during Li and Na plating/stripping.Therefore,the symmetric batteries of Li@Pt–Cu foam and Na@Pt–Cu foam have both achieved long‐term cycling stability even at ultrahigh areal capacity at 20 mAh cm−2.
