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Patterning of controllable surface wettability has attracted wide scientific attention due to its importance in both fundamental research and practical applications. In particular, it is crucial to form clear image areas and non-image areas in printing techniques based on wetting and dewetting. This review summarizes the recent research on and applications of patterning of controllable surface wettability for printing techniques, with a focus on the design and fabrication of the precise surface wettability patterning by enhancing the contrast of hydrophilicity and hydrophobicity, such as superhydrophilicity and superhydrophobicity. The selected topics mainly include patterned surface wettability for lithographic printing with different plate-making techniques, patterned surface wettability for microcontact printing with a patterned wetting stamp and special wettability mediated patterning microtransfer printing, patterned surface wettability for inkjet printing with controllable surface wettability of the substrate and printing head to ink, and patterned surface wettability by a combination of different printing techniques. A personal perspective on the future development and remaining challenges of this research is also briefly discussed.

Oil contaminated water is a common problem in the world, thus to effectively separate water and oil is an urgent task for us to resolve. By control of surface wettability of a solid substrate, both superhydrophobicity and superoleophilicity on a film can be realized, which is necessary for water and oil separation. Here we report a stable superhydrophobic and superoleophilic ZnO-coated stainless steel mesh film with special hierarchical micro/nanostructures that can be used to separate a water and oil mixture effectively. Namely, the film is superhydrophobic and water cannot penetrate the mesh film because of the large negative capillary effect, while the film is superoleophilic and liquid paraffin oil can spread out quickly and permeate the mesh film spontaneously due to the capillary effect. A detailed investigation indicates that microscale and nanoscale hierarchical structures and the appropriate size of the microscale mesh pores on the mesh films play an important role in obtaining the excellent water and oil separation property. This work provides an alternative to current separation meshes and is promising in various important applications such as separation and filtration, lab-on-a-chip devices and micro/nanofluidic devices.

Controllable liquid transport on surface is expected to occur by manipulating the gradient of surface tension/Laplace pressure and external stimuli, which has been intensively studied on solid or liquid interface. However, it still faces challenges of slow response rate, and uncontrollable transport speed and direction. Here, we demonstrate fast responsive and controllable liquid transport on a smart magnetic fluid/nanoarray interface, i.e., a composite interface, via modulation of an external magnetic field. The wettability of the composite interface to water instantaneously responds to gradient magnetic field due to the magnetically driven composite interface gradient roughness transition that takes place within a millisecond, which is at least 1 order of magnitude faster than that of other responsive surfaces. A water droplet can follow the motion of the gradient composite interface structure as it responds to the gradient magnetic field motion. Moreover, the water droplet transport direction can be controlled by modulating the motion direction of the gradient magnetic field. The composite interface can be used as a pump for the transport of immiscible liquids and other objects in the microchannel, which suggests a way to design smart interface materials and microfluidic devices.

In nature, fluid manipulations are ubiquitous in organisms, and they are crucial for many of their vital activities. Therefore, this process has also attracted widescale research attention. However, despite significant advances in fluid transportation research over the past few decades, it is still hugely challenging to achieve efficient and nondestructive droplet transportation owing to contamination effects and controllability problems in liquid transportation applications. To this end, inspired by the motile microcilia of micro‐organisms, the superhydrophobicity of lotus leaves, the underwater superoleophobicity of filefish skin, and pigeons' migration behavior, a novel manipulation strategy is developed for droplets motion. Specifically, herein, a superwettable magnetic microcilia array surface with a structure that is switchable by an external magnetic field is constructed for droplet manipulation. It is found that under external magnetic fields, the superhydrophobic magnetic microcilia array surface can continuously and directionally manipulate the water droplets in air and that the underwater superoleophobic magnetic microcilia array surface can control the oil droplets underwater. This work demonstrates that the nondestructive droplet transportation mechanism can be used for liquid transportation, droplet reactions, and micropipeline transmission, thus opening up an avenue for practical applications of droplet manipulation using intelligent microstructure surfaces.