Bioinspired shape-memory graphene film with tunable wettability

Functional materials with specific surface wettability play an important role in a wide variety of areas. Inspired by nature's Nepenthes pitcher plant, we present a novel slippery film with tunable wettability based on a shape-memory graphene sponge. The porous graphene sponge coated with shape-memory polymer was used to lock in inert lubricants and construct slippery surfaces to repel different liquids. The superelasticity and high strength, together with good electrical conductivity, of the graphene sponge imparted the graphene/polymer hybrid films with fast recoverable shape-memory properties. Various droplets could slip on the compressed film with a lubricant-covered surface, but the droplets would be pinned when the shape-memory graphene film rebounded due to electrical stimulation, which caused the penetration of the infused lubricant into the pores and the exposure of rough topography film surfaces. The electrothermally dynamic tuning approach was stable and reversible; thus, the shape-memory graphene film was imparted with controlled slippery properties and functions that would be amenable to a variety of applications, such as liquid handling for microplates.