Novel water tumbler with high floatation and adhesion using special wettability effects

Abstract

A tumbler is a device that can tumble over and then straighten up by itself due to a low gravity center. In this work, we design and fabricate a kind of novel water tumbler using a super-hydrophobic+Janus+super-hydrophilic (SHB+Janus+SHL) structure, which can achieve high floatation and adhesion. Based on the inspiration of Argyroneta aquatica, 9 groups of copper foam assemblies with different combinations are designed, and their load capacity and adhesion force to water are compared. It is found that the combination structure of SHB+Janus+SHL can achieve both buoyancy and maximum adhesion force at the same time. The SHB+Janus+SHL can absorb more water in water, so that this device's center of gravity is lower. Due to the design with a low gravity center and high adhesion force, the stability of the balance is improved. If this device is overturned, this device can keep a stable state with the super-hydrophobic part above water and the super-hydrophilic part below water under the action of buoyancy, gravity, repulsive force, and adhesive force, which is similar to the tumbler. Depending on this excellent stability, a model ship with a SHB+Janus+SHL structure can keep steady even when tumbling over under the action of an external force and a wind wave. This work provides ideas for improving the stability of water vehicles and the design of high floating robots on water.