8. Surface Energy, Wetting & Surface Roughness
What you'll learn
- The relationship between surface energy and surface wetting
- The dynamics that determine how a liquid will react on a given surface
- The role of surface texture on whether a liquid will wet a surface
- Applications, and the ways in which engineers modify surfaces in order to achieve a desired wettability
- No prerequisites. However, we recommend viewing Modules 1-3 of this Surface Texture and Tribology Short Course to learn more about surface texture, spatial wavelengths, and surface texture parameters.
Why does water bead up on a waxed surface? Why does ink form a good image on some paper but runs and smears on others?
In this module we delve into the dynamics of surface energy/ wetting. Many forces come together to affect whether a drop of liquid might spread out onto a surface instead of beading up and rolling away. Surface texture plays a central role, as you might expect, but it is only part of the answer. We introduce the concepts of “surface tension” and “hysteresis” and how these various characteristics help us predict whether a surface will be “hydrophilic” or “hydrophobic.” We also examine the surface texture parameters that help to quantify the wettability of a given surface. And, lastly, we show how researchers and engineers in various fields are modifying surface textures in order to achieve a desired wettability—whether it’s to keep your windshield clear of rain or reduce the smudges on your phone.
This is Module 8 of the Surface Texture and Tribology Short Course. The full course is available on udemy, or you can select the individual course modules of interest to you. Enter "surface roughness texture tribology" in the udemy search bar to browse the full course and modules.
Who this course is for:
- Scientists, engineers, technicians and students in the fields of automotive, medical device, aerospace, materials, polymers, and others
In 1994, Dr. Cohen established Michigan Metrology to help engineers and scientists solve problems related to “Squeaks, leaks, friction, wear, appearance, adhesion and other issues,” using 3D Surface MicroTexture Measurement and Analysis.
Dr. Cohen is a past Chairman of the STLE-Detroit section and has been active with the ASME B46.1 committee on surface texture since 1988, having served as Chair from 2005-2011. Dr. Cohen is also a Subject Matter Expert for the ISO surface metrology activities.
Dr. Cohen has an undergraduate degree in Physics from the University of Michigan, Dearborn, and graduate degrees in Physics and Optical Sciences from the University of Arizona. Early in his career, Dr. Cohen worked with IBM on optical disk drive development. He later joined WYKO Corporation as Product Manger and later became Vice President, leading the development of 3D surface texture metrology instrumentation.
Dr. Cohen has developed this class over the past 20 years having presented the material at numerous client locations as part of his training and consulting activities. Typically once a year the class is offered to a general audience in the Livonia, MI area.