Liquid spreading along nanostructured superhydrophilic lanes

Liquids can be sculpted by spreading along predefined rough hydrophilic lanes surrounded by superhydrophobic backgrounds. We find that two distinct types of liquid spreading arise depending on the lane width. While only a fringe film wicks into the nanoroughness of very narrow lanes, a thick bulk film spreads along wide lanes. We theoretically analyze the spreading rates of films, which change power laws in the course of spreading, and corroborate the theory with experiments.