Experimental study the effect of surface roughness of a material on its hydrophobicity

Abstract

Abstract. To investigate the effect of trapped gas and surface roughness, it is necessary to study more deeply the hydrophobic nature of a material which has a different surface roughness value. This research was conducted experimentally, by first preparing materials that have different grain sizes. Then measuring contact angles, mapping surface roughness, and observing droplets when in contact with the material. This study shows that the increase in droplet volume affects the contact angle formed, the greater the droplet volume the droplet surface tension capability is getting weaker. The smaller the grain size, the higher the contact angle formed, this is due to the particle size that supports the droplet surface, when the particle size is small, the surface tension formed is greater so that the droplet has a high contact angle. Micro/nano size bubbles that spread evenly on the surface of hydrophobic material strongly support the occurrence of hydrophobic properties in a material. Keywords: trapped gas, surface roughness, hydrophobic nature, grain size