Fabrication of hydrophobic surfaces using micro-electro discharge machining
Ching, Zai Ting
Date of Issue2015
School of Mechanical and Aerospace Engineering
The hydrophobic surface of the lotus leaf has many desirable properties. A hydrophobic surface prevents the build-up of foreign or water molecules on the surface and exhibit self-cleaning properties. A rough surface results in a high contact angle, which implies a hydrophobic surface. To create a hydrophobic surface on a metal specimen, Micro Electro Discharge Machining was utilised to roughen the surface of the material. In the process, the hydrophobicity of the metal surface was increased. Aluminium, brass and copper were the work piece used in the experiment. It was found that for aluminium work piece, brass electrodes gave the highest average contact angle. Heat was transferred to aluminium work piece due to its high thermal conductivity while its lower melting point would cause the material to melt. For brass work piece, copper electrodes was found to give the highest average contact angle. There may be some inaccuracy in the results obtained from brass work piece as since copper has a higher thermal conductivity, heat should transfer to the copper electrode instead. For copper work piece, brass electrodes was found to give the highest average contact angle as heat was transferred to the copper work piece due to its higher thermal conductivity. However, the material removal rate would be low because of its high melting point. The effect of diameter and thickness of the electrode was not apparent in this study. Surface roughness of all the work materials was increased due to material being removed from the work pieces. From the results gathered, the choice of electrode and work piece material had a more pronounced effect on the roughness and therefore contact angle of machined surface.
Final Year Project (FYP)
Nanyang Technological University