Complementary\nSuperwetting Structures Treated by a\nFemtosecond Laser for Simultaneous Spontaneous Directional Transport of Water Droplets and Underwater\nBubbles

The control of fluid transport is crucial and has broad\napplications\nin the fields of intelligent systems and microfluidics. However, current\nstudies usually focus on the spontaneous directional transport of\na single type of fluid or require complex preparation processes. In\nthis paper, the single femtosecond laser direct processing of complementary\nsuperwetting structures using polyimide/polytetrafluoroethylene is\nproposed, for the first time, to realize simultaneous spontaneous\ndirectional transport of water droplets and underwater bubbles without\nany additional energy or chemical treatment. The flexible laser fabrication\nenables the creation of diverse transport structures, facilitating\nthe achievement of linear and curvilinear fluid transport on superwetting\nstructures. In addition, relevant applications in self-transporting\nchemical reactions and bubble switching are presented. This technique\nprovides a novel approach to fabricate patterned superwetting surfaces\nfor applications in intelligent transport, microbiology, and chemistry.