Understanding the time-dependent mechanical behavior of tough and viscoelastic hydrogels under complex external loading is crucial.In this study,we utilized tough and viscoelastic hydrogels synthesized through the cop...Understanding the time-dependent mechanical behavior of tough and viscoelastic hydrogels under complex external loading is crucial.In this study,we utilized tough and viscoelastic hydrogels synthesized through the copolymerization of methacrylic acid and methacrylamide as a model system to investigate their mechanical behavior under multiaxial stretching across a wide range of strain rates.Three stretching modes examined were uniaxial,pure shear,and equal biaxial stretching.Our findings show that under equal biaxial stretching,the hydrogels exhibit higher mechanical properties and energy dissipation compared to uniaxial and pure shear stretching,owing to the greater contribution of hydrogen bonds to energy dissipation in the former stretching mode.Additionally,employing the time-elongation separability method during the stretching process,we observed that the relaxation of dynamic hydrogen bonds in the hydrogels only depends on stretching time,independent of the elongation ratio and stretching modes.We anticipate that this study will yield valuable contributions to the design of durable load-bearing soft materials,particularly in dealing with complex deformation and strain rate responses.展开更多
基金supported by the Major Program of National Natural Science Foundation of China(Grant No.11932007)National Natural Science Foundation of China(Grant No.11972011)+3 种基金Natural Science Foundation of Guangdong Province(No.2023A1515012049)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2019ZT08Y318)the Recruitment Program of Guangdong(No.2016ZT06C322)the 111 Project(No.B18023),China.
文摘Understanding the time-dependent mechanical behavior of tough and viscoelastic hydrogels under complex external loading is crucial.In this study,we utilized tough and viscoelastic hydrogels synthesized through the copolymerization of methacrylic acid and methacrylamide as a model system to investigate their mechanical behavior under multiaxial stretching across a wide range of strain rates.Three stretching modes examined were uniaxial,pure shear,and equal biaxial stretching.Our findings show that under equal biaxial stretching,the hydrogels exhibit higher mechanical properties and energy dissipation compared to uniaxial and pure shear stretching,owing to the greater contribution of hydrogen bonds to energy dissipation in the former stretching mode.Additionally,employing the time-elongation separability method during the stretching process,we observed that the relaxation of dynamic hydrogen bonds in the hydrogels only depends on stretching time,independent of the elongation ratio and stretching modes.We anticipate that this study will yield valuable contributions to the design of durable load-bearing soft materials,particularly in dealing with complex deformation and strain rate responses.
