Wettability Studies of Laser-Treated Materials

Abstract

Laser generated surface structures and surface cleaning was applied for the modification of wettability with a view towards developing these processes for industrial applications. The surface texturing experiments were performed using a diode pumped solid state (DPSS) Nd:YVO4 laser operating at wavelengths of 1064 nm. Laser surface microstructuring on metals was studied in an effort to produce hydrophobic and super-hydrophobic surfaces on metals. It was found that the roughness change produced by laser processing induces composite wetting when water droplets are introduced to the surface. Contact angle measurements and small angle X-Ray Diffraction (XRD) analysis of laser processed stainless steel (AISI 304) have shown that surface wettability decreased over a period of three months. Significant increase in contact angle (~140o) was achieved, therefore a decrease in wettablity, was induced by electron irradiation on the laser treated surface. After ultrasonic bath in acetone and ethanol, the laser structured samples had an immediate increase in contact angle for acetone, but with a gradual increase with ethanol.The surface wettability dependency with exposure time was found to be influenced by the combined effects of surface morphology, surface chemistry and surface free energy.

Date of Award	1 Aug 2014
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Zhu Liu (Supervisor)