Topological Design of Floaters with Plug‐In Functions

Abstract Floaters with exposed surfaces are essential for applications in heterogeneous catalysis, microdetectors, and solar evaporation. Conventional floaters, however, rely on specific low‐density or hydrophobic materials, restricting their adaptability. This study introduces a topological design principle, enabling dense, hydrophilic materials to float stably on water. The proposed hydrophilic cellular sheet (HCS) features a water‐attractive substrate patterned with a crown‐shaped pore array, fabricated via digital light processing. These unique pores trap air effectively, providing exceptional buoyancy. The modular design of the HCS allows for versatile plug‐in functionalities by utilizing the pores as reservoirs for functional beads. The combination of multi‐HCSs enables on‐water information encryption and decryption. Furthermore, the HCS demonstrates potential as supporting devices in triboelectric nanogenerators, promising in wave energy harvesting. This work establishes a versatile platform for designing adaptable floaters with integrated functionalities, expanding their utility in areas, such as interface carriers, encryption devices, and renewable energy collection.