Evaluation of air layer behavior on patterned PTFE surfaces under underwater environment conditions

The ability to reduce the friction resistance between water and solid surface is one of the key functions of superhydrophobic surfaces. Reducing the frictional resistance between a solid surface and water is called drag reduction. This function is induced by the air layer formed at interface between the water and a superhydrophobic surface. The sustainability of the air layer is a key factor to induce stable drag reduction effect. Despite the importance of the air layers, only a few studies on the air layer sustainability have been reported. Therefore, in this study, various experiments on the air layer sustainability and drag reduction were carried out under the simulated underwater environment. Superhydrophobic PTFE surfaces with groove patterns having several hundred micrometers were applied in the experiments. As a result, it was possible to optimize groove pattern shape that can effectively maintain the air layer under hydrostatic pressure of 100 kPa. Furthermore, the effect of the groove patterns on the drag reduction was analyzed using water circulation system developed in this work.

Automated summary

The ability to reduce friction resistance between water and a solid surface is a key function of superhydrophobic surfaces. This study investigated the sustainability of air layers and drag reduction on superhydrophobic surfaces with groove patterns. The results showed that optimizing the groove pattern shape can effectively maintain the air layer and improve drag reduction.