Experimental study of liquid spreading on pattern surface

• Main Author: Lee, Chia Seah.
• Other Authors: Fan Hui
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/16128
• Institution: Nanyang Technological University

To obtain more knowledge and insights of how the liquid droplet affects the application of Micro Electro Mechanical Systems (MEMS), experiments involving small volume of liquid are favoured. The study of nano or micro level sizes could not be scaled down from high level, hence this experiment serves as a fundamental study for micro level structures with the micro sized patterns on the surface. A mould was made to hold the small stainless steel balls in place for the compression process on the Shape-Memory Polymer (SMP) and moulding the silicone samples during the curing process. The SMP was polished and compressed with the stainless steel balls to serve as templates for the fabrication of silicone samples. The contact angle of water droplet landing on the patterned silicone surface was measured using FTA 200, a high speed camera and FTA 32, the software for analysing contact angle. The surface profile of the silicone samples were analysed together with the contact angles measured from the droplets landing on these patterned surfaces. It was found that a smoother surface profile, in terms of the depths of grooves, heights of protrusions and the availability of plateau on the surface have influences over the contact angles. The contact angles of water droplet on silicone samples made from 0.4mm diameter balls have smaller discrepancy and are close to the contact angle of water droplet on flat silicone surface. Whereas, the contact angles of water droplet on silicone samples made from 1mm diameter balls have a larger range of contact angles at the different views.