Characterization of surface wettability

• Main Author: Tan, Jasmine Jie Min
• Other Authors: Zhang Yi
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/150732
• Institution: Nanyang Technological University

Objective: The author has conducted a series of experiments to characterize and investigate the surface wettability of polydimethylsiloxane (PDMS) after the surface modification technique called Slippery Lubricant-Infused Porous Surfaces (SLIPS). Methods: Different cross-linking ratios of PDMS (1:5, 1:10, and 1:15) will prepared and immersed in varying viscosity of silicone oil (10 cSt, 100 cSt, and 500 cSt) and soaked for the different duration (30 mins, 1 hour, 3 hours, 24 hours and 48 hours). After soaking, results were characterized by 1) contact angle measurement, 2) scanning electron microscopy, 3) degree of swelling and 4) surface roughness. Results: After infusion of silicone oil, it is demonstrated that a higher cross-linking ratio will result in higher contact angle, which will lead to more swelling and higher surface roughness. Similarly, a longer soaking duration will lead to more swelling and higher surface roughness of the samples. It is shown that the viscosity of the silicone oils might not be a big factor in affecting the surface wettability of the samples. Conclusion: SLIPS will be an ideal and simple surface modification for PDMS. In addition, the highest surface wetting is achieved through the lowest cross-linking ratio soaked in the least viscosity of silicone oil.