The utilization of nanoporous copper(np-Cu)as a metallic actuator has gained attention in recent years due to its cost-effectiveness in comparison to other precious metals.Despite this,the enhancement of np-Cu’s actuation performance remains a challenge due to limitations in its strain amplitude and actuation rate.Additionally,np-Cu has been deemed as a promising material for solar absorption due to its localized surface plasmon resonance effect.However,practical applications such as solar steam generators(SSGs)utilizing np-Cu have yet to be documented.In this study,we present the development of hierarchically nanoporous copper(HNC)through the dealloying of a eutectic Al-Cu alloy.The hierarchical structure of the HNC features a combination of ordered flat channels and randomly distributed continuous nanopores,which work in synergy to improve actuation performance.The ordered flat channels,with a sub-micron scale,facilitate rapid mass transport of electrolyte ions,while the nano-sized continuous pores,due to their large specific surface area,enhance the induced strain.Our results indicate that the HNC exhibits improved actuation performance,with a two times increase in both strain amplitude and rate in comparison to other reported np-Cu.Additionally,the HNC,for the first time,showcases excellent solar steam generation capabilities,with an evaporation rate of 1.47 kg·m^(-2)·h^(-1) and a photothermal conversion efficiency of 92%under a light intensity of 1 kW·m^(-2),which rivals that of nanoporous gold and silver film.The enhanced actuation performance and newly discovered solar steam generation properties of the HNC are attributed to its hierarchically porous structure.
Tightly integrating actuation,computation,and sensing in soft materials allows soft robots to respond autonomously to their environments.However,fusing these capabilities within a single soft module in an effi-cient,programmable,and compatible way is still a significant challenge.Here,we introduce a strategy for integrating actuation,computation,and sensing capabilities in soft origami.Unified and plug-and-play soft origami modules can be reconfigured into diverse morphologies with specific functions or reprogrammed into a variety of soft logic circuits,similar to LEGO bricks.We built an untethered autonomous soft turtle that is able to sense stimuli,store data,process information,and perform swimming movements.The function multiplexing and signal compatibility of the origami minimize the number of soft devices,thereby reducing the complexity and redundancy of soft robots.Moreover,this origami also exhibits strong damage resistance and high durability.We envision that this work will offer an effective way to readily create on-demand soft robots that can operate in unknown environments.
