Surface wettability modification of cyclic olefin polymer by femtosecond laser irradiation

• Main Author: Yong, Chui Shan.
• Other Authors: Lam Yee Cheong
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/50431
• Institution: Nanyang Technological University

This study investigates the controlled modifications of surface wettability of cyclic olefin polymer (COP) by the use of femtosecond laser pulses at various fluences by changing the defocusing distance. A wide range of water contact angles (WCA) were achieved, surfaces ranged from highly hydrophilic, to hydrophobic, to highly hydrophobic, by varying the defocusing distance. The laser fluence varies indirectly proportionately to the modulus of focal distances. The surface morphology, roughness and stability of the modified COP samples were analyzed to investigate the relations between them and the wetting behavior of laser ablated COP surfaces. WCA of <10° was achieved by irradiating the COP sample at the focal distance. From -0.5 mm to -5 mm and +0.5 mm to +4.5 mm, hydrophobic surfaces were achieved. Among these, the highest WCA attained were 149.3° at defocusing distance of -4 mm.