A humidity-driven flexible carbon nitride film with multiple deformations

Smart materials that change their properties in response to external stimuli are of interest for emerging application in energy harvesting. Here, we employ the facile thermal condensation method to synthesize flexible carbon nitride films that can convert slight variations in surrounding humidity to multiple distinct deformations. A quick jumping motion is generated in response to sudden increases in humidity, whereas subtle changes in humidity (i.e., an increase of 2%) cause the film to change shape from tubular to arched. When exposed to humidity fluctuations, the film moves forward by about 2 mm. These results show the prepared carbon nitride film has a great potential in water-driven generators.