Study of Drop Impact on Slippery Lubricant Infused Surfaces

Slippery lubricant infused surfaces (SLIPS) have gained interest because of their anti-icing capabilities. Experiments have shed light on the physical aspect of the water drop interacting with SLIPS, little is known about the dynamics of the drop and SLIPS interaction. Recent studies indicate the problem of cloaking, resulting from surface energy differences between the low energy lubricants and high energy drops. But the water drops impacting on lubricants have different outcomes in terms of spreading and retracting. It is critical to study the dynamic behavior of the cloaking problem since cloaking induces lubricant drainage and thus renders the anti-icing property of the surface. In this study, we report our drop dynamics study to understand the dynamic behavior and the mechanism of deformation of drops and lubricants. A very important aspect of cloaking behavior is captured by varying the interfacial tensions, where Neumann triangle is used at the junction of the three phases (water-lubricant-air) and the resulting force-balance calculation dictates the movement of the triple point. Commonly used lubricant from experimentally published results is used as a basis for our simulation, and such values are then systematically varied to understand the energy differences and spreading coefficients that indicates the cloaking phenomenon of an impacting water drop on a lubricant. Our simulation captures the cloaking phenomena with the same size droplet but with varying speed of the impact at varying interfacial tensions. Through our exploration of the drop impact on lubricants, we observe that varying interfacial tension between the water-lubricant stabilizes the droplet and SLIPS.