Understanding the macroscopical flexibility/fragility of nanoporous Ag:Depending on network connectivity and micro-defects

The effective engineering applications of nanoporous metals(NPMs)in flexible energy storage and wearable healthcare biosensor monitoring require its uniform ligaments network,specifically crack-free and flexible monolithic bodies.However,the macroscopic fragility of NPMs restricts their applications in wearable electronics fields.Here we focus on the synthetization of highly flexible NPMs.The effects of structural factors,e.g.ligament-network connectivity and micro-cracks on the mechanical properties of nanoporous Ag(np Ag)are investigated.The well-interconnected np Ag metal exhibits higher tensile strength,nanohardness and Vickers hardness than those for the ill-interconnected np Ag metal.The quality of the network connectivity dominates the strength and hardness of the np Ag.The flexibility/fragility is determined by the micro-crack in np Ag.The crack-free np Ag exhibits good flexible behavior.When micro-cracks are introduced,the np Ag becomes fragile.The control of soft volume shrinkage rate(Vsr)and slow surface diffusivity(Ds)effectively suppresses the crack initiation and propagation of as-formed np Ag.These results provide useful insights to synthesize more flexible and crack-free NPM materials for effective use in public wearable electronics and diverse flexible engineering applications in the future.