Static wetting characteristics of micro-textured stainless steel surfaces under uniaxial loading condition

The wetting behaviour associated with the surface micro asperities is investigated on the groove and pillar textured SS304 solid surface which is widely used in the flight vehicles where the stresses are induced by uniaxial compressive loads for both positive and negative curvature. By varying the applied load on the groove-textured surfaces in the direction perpendicular to grooves, the positive curvature shows a decrease in static contact angle initially then increases for further increase in deflection; however, the negative curvature induced by the same applied load shows an opposite trend. At the same time, in the pillar-textured surface, the static contact angle decreases with increase in applied load for the positive curvature and the same wetting parameter shows an opposite trend for the negative curvature. This phenomenon is mainly attributed to the pinning behaviour of the three phase contact line of the liquid drop on these two surfaces.