Carnivorous plants inspired shape-morphing slippery surfaces

Carnivorous plants,for instance,Dionaea muscipula and Nepenthes pitcher plant,inspired the innovation of advanced stimuli-responsive actuators and lubricant-infused slippery surfaces,respectively.However,hybrid bionic devices that combine the active and passive prey trapping capabilities of the two kinds of carnivorous plants remain a challenge.Herein,we report a moisture responsive shape-morphing slippery surface that enables both moisture responsive shapemorphing and oil-lubricated water repellency for simultaneous active-and passive-droplet manipulation.The moisture deformable slippery surface is prepared by creating biomimetic microstructures on graphene oxide(GO)membrane via femtosecond laser direct writing and subsequent lubricating with a thin layer of oil on the laser structured reduced GO(LRGO)surface.The integration of a lubricant-infused slippery surface with an LRGO/GO bilayer actuator endows the actuator with droplet sliding ability and promotes the moisture deformation performance due to oil-enhanced water repellency of the inert layer(LRGO).Based on the shape-morphing slippery surface,we prepared a series of proof-of-concept actuators,including a moisture-response Dionaea muscipula actuator,a smart frog tongue,and a smart flower,demonstrating their versatility for active/passive trapping,droplet manipulation,and sensing.

Heterogeneous self-healing assembly of MXene and graphene oxide enables producing free-standing and self-reparable soft electronics and robots

Self-healing materials(SHMs)with unique mechanical and electronic properties are promising for self-reparable electronics and robots.However,the self-healing ability of emerging two-dimensional(2D)materials,for instance,MXenes,has not been systematically investigated,which limits their applications in self-healing electronics.Herein,we report the homogeneous self-healing assembly(homoSHA)of MXene and the heterogeneous self-healing assembly(hetero-SHA)of MXene and graphene oxide(GO)under moisture treatments.The self-healing mechanism has been attributed to the hydration induced interlayer swelling of MXene and GO and the recombination of hydrogen bond networks after water desorption.The multiform hetero-SHA of MXene and GO not only enables facile fabrication of free-standing soft electronics and robots,but also endows the resultant devices with damage-healing properties.As proof-of-concept demonstrations,free-standing soft electronic devices including a generator,a humidity sensor,a pressure sensor,and several robotic devices have been fabricated.The hetero-SHA of MXene and GO is simple yet effective,and it may pioneer a new avenue to develop miniature soft electronics and robots based on 2D materials.