Integrated conductive elastomers with excellent mechanical performance,stable high conductivity,self-healing capabilities,and high transparency are critical for advancing wearable devices.Nevertheless,achieving an opt...Integrated conductive elastomers with excellent mechanical performance,stable high conductivity,self-healing capabilities,and high transparency are critical for advancing wearable devices.Nevertheless,achieving an optimal balance among these properties remains a significant challenge.Herein,through in situ free-radical copolymerization of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate(TEEA)and vinylimidazole(VI)in the presence of polyethylene glycol(PEG;Mn=400),tough P(TEEA-co-VI)/PEG elastomers with multiple functionalities were prepared,in which P(TEEA-co-VI)was dynamically cross-linked by imidazole-Zn^(2+)metal coordination crosslinks,and physically blended with PEG as polymer electrolyte to form a homogeneous mixture.Notably,Zn^(2+)has a negligible impact on the polymerization process,allowing for the in situ formation of numerous imidazole-Zn^(2+)metal coordination crosslinks,which can effectively dissipate energy upon stretching to largely reinforce the elastomers.The obtained P(TEEA-co-VI)/PEG elastomers exhibited a high toughness of 10.0 MJ·m^(-3) with a high tensile strength of 3.3 MPa and a large elongation at break of 645%,along with outstanding self-healing capabilities due to the dynamic coordination crosslinks.Moreover,because of the miscibility of PEG with PTEEA copolymer matrix,and Li+can form weak coordination interactions with the ethoxy(EO)units in PEG and PTEEA,acting as a bridge to integrate PEG into the elastomer network.The resulted P(TEEA-co-VI)/PEG elastomers showed high transparency(92%)and stable high conductivity of 1.09×10_(-4) S·cm^(-1).In summary,the obtained elastomers exhibited a well-balanced combination of high toughness,high ionic conductivity,excellent self-healing capabilities,and high transparency,making them promising for applications in flexible strain sensors.展开更多
The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm...The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52273023,51973103,and 21774069).
文摘Integrated conductive elastomers with excellent mechanical performance,stable high conductivity,self-healing capabilities,and high transparency are critical for advancing wearable devices.Nevertheless,achieving an optimal balance among these properties remains a significant challenge.Herein,through in situ free-radical copolymerization of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate(TEEA)and vinylimidazole(VI)in the presence of polyethylene glycol(PEG;Mn=400),tough P(TEEA-co-VI)/PEG elastomers with multiple functionalities were prepared,in which P(TEEA-co-VI)was dynamically cross-linked by imidazole-Zn^(2+)metal coordination crosslinks,and physically blended with PEG as polymer electrolyte to form a homogeneous mixture.Notably,Zn^(2+)has a negligible impact on the polymerization process,allowing for the in situ formation of numerous imidazole-Zn^(2+)metal coordination crosslinks,which can effectively dissipate energy upon stretching to largely reinforce the elastomers.The obtained P(TEEA-co-VI)/PEG elastomers exhibited a high toughness of 10.0 MJ·m^(-3) with a high tensile strength of 3.3 MPa and a large elongation at break of 645%,along with outstanding self-healing capabilities due to the dynamic coordination crosslinks.Moreover,because of the miscibility of PEG with PTEEA copolymer matrix,and Li+can form weak coordination interactions with the ethoxy(EO)units in PEG and PTEEA,acting as a bridge to integrate PEG into the elastomer network.The resulted P(TEEA-co-VI)/PEG elastomers showed high transparency(92%)and stable high conductivity of 1.09×10_(-4) S·cm^(-1).In summary,the obtained elastomers exhibited a well-balanced combination of high toughness,high ionic conductivity,excellent self-healing capabilities,and high transparency,making them promising for applications in flexible strain sensors.
基金financially supported by the Aeronautical Science Foundation of China(No.2012ZF53080)the Shaanxi Province Science and Technology Research and Development Program of China(No.2013K08-11)+1 种基金the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University(No.SKLSP201009)the 111 Project of China(No.B08040)
文摘The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.
