“…Droplet transports on functional interfaces with anisotropic wettability have drawn keen yet continuously increasing research interest from academic communities due to their great potential applications in water purification/collection [1], [2], [3], [4], chemical micro-reactor [5], [6], [7], biomedical analysis [8], [9], [10] and so on. A common method for droplet transport is to design nonuniformly wettable surfaces with chemical and/or topographical gradients, such as superhydrophobicsuperhydrophilic patterns [11], [12], [13], wedge-shaped structures [14], [15], [16], [17], lubricant meniscus [18], [19], etc.…”