Mimicking Nature's Mechanisms: Creating a Directionally Omniphobic Liquid Infused Surface Coating

Open Access
Author:
Wang, Jonathan Waylen
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Tak Sing Wong, Thesis Supervisor
  • Domenic Adam Santavicca, Honors Advisor
Keywords:
  • directional surface
  • omniphobic surface
  • bio-inspired engineering
  • anisotropic wetting
Abstract:
Nature is often the inspiration for new emerging technology today. In particular, several species of plant and animal life use structured surfaces to directionally transfer liquids. A butterfly’s hydrophobic wings are structured so that water is directionally repelled away from the body. The Nepenthes pitcher plant exhibits a structured surface that when wetted, can repel various liquids and null the adhesive forces used by insects to scale walls. In this thesis, these two mechanisms were combined into one synthetic surface which aimed to directionally repel various liquids of differing surface tensions. Four microgrooved surfaces of differing groove dimensions were created for testing. To test the effectiveness of these directional surfaces, the height of the lubricant used to coat the surfaces and produce a thin film was measured at various spin coating speeds. The surface samples were then tested with an inclinometer to measure the sliding angle difference between the parallel and perpendicular orientations at the corresponding spin speed and lubricant height. With this data, it was concluded that the directional surfaces showed significant ability to directionally repel water, hexadecane, and octane test droplets. Some potential further work is then discussed which could help explain any discrepancies within the test data.