Pump-free oil droplet transfer by combining microfibre array and superoleophobic mesh

Abstract

The wetting strategies of plants have inspired a wide range of biomimetic surfaces, such as water-droplet-capturing surfaces that imitate the fibrous system of dandelion seeds and water-droplet-repelling surfaces that mimic the superhydrophobicity of lotus leaves. Here, we developed an oil droplet manipulation device by causing a movable microfibre array to penetrate a superoleophobic mesh. The microfibre array tended to capture an oil droplet, and the superoleophobic mesh allowed the oil droplet to roll easily. The on/off switching of the device’s adhesion to oil droplets was controlled by moving the microfibre array. Our device could be used effectively to capture, transport and release four kinds of oil droplets (glycerol, rapeseed oil, peanut oil, and 100# machinery oil), which may enable the exploration of a wide range of applications involving switchable adhesion for handling oil droplets.