Physics of surfaces and interfaces: capillarity, wetting and adsorption phenomena

When reducing matter to the nanoscale the importance of surfaces and interfaces increases tremendously. This course covers the physics of the related phenomena with particular focus on interfaces with liquids, i.e. surface/interfacial tension, capillarity, wetting, hydrophilicity/hydrophobicity and transport process during solvent evaporation. Definitions and explanations of fundamental concepts are complemented by descriptions of related nanotechnological processes such as critical point drying and nanostructuring for inducing superhydrophobic surfaces. Adsorption/desorption phenomena and the process of determining surface area using gas adsorption are also discussed. A substantial component of the course is a project work that you will carry out in teams. You will come up with the goal of the project yourself, the only limitation being that the project deals with processes and phenomena discussed in the course.

Main course book

• Capillarity and Wetting Phenomena: Drops, Bubbles, Pearls, Waves (Springer)
• P. G. de Gennes, F. Brochard-Wyart and D. Quéré

Useful additional books:

• Further useful books
• Applied Colloid and Surface Chemistry (Wiley)
  Richard M. Pashley and Marilyn Karaman
• An Introduction to Interfaces and Colloids: The Bridge to Nanoscience (World Scientific)
  John C. Berg

Fall semester 2013
The class starts on Tuesday September 3rd 2013 at 9:30 am in room 220-204 (Gwanak campus). The following lectures will be as follows:
PDFs of the slides shown during the lectures will be available for download from the course resources page once the course has started.
Schedule (week by week):

1. Introduction to surface/interface science & its applications. Surface/interfacial tension: definition and origin. Cohesive interactions in liquids and at liquid-solid interfaces.
2. Wetting, contact angle and contact angle hysteresis. Surface treatments for influencing wetting properties. Wenzel and Cassie-Baxter models for inhomogeneous surfaces.
3. No class due to travel + 추석
4. Laplace pressure and the Young-Laplace equation. Laplace (capillary) pressure, capillary bridging, capillary condensation and the Kelvin equation. Critical point drying. How to measure surface tension.
5. Definition of surface curvature; minimal surfaces. Shape and size of drops and liquid lenses under varying circumstances.
6. Different types of wetting. “Superhydrophilic” and superhydrophobic surfaces. Hydrodynamics of interfaces: thin films, waves and ripples.
7. Project presentations + voting. Project work session 1
8. Rayleigh-Taylor and Rayleigh-Plateau instabilities. Science and technology of inkjet printing.
9. Mid-term exam. Dewetting and dynamic motion of the contact line.
10. Project work session 2.
11. Liquids at soft or hot surfaces: elastic wetting on PDMS and Leidenfrost drops. Surfactants and their adsorption at, and influence on, interfaces.
12. Transport phenomena and effect of gradients. Evaporation of solvent from a suspension or solution droplet: Marangoni effect, coffee ring effect.
13. Electrocapillarity, electroosmosis, electrowetting: fundamentals and applications. Project work session 3.
14. Thermodynamics of adsorption; Gibbs adsorption equation. Surface area determination by gas adsorption experiments (Langmuir and BET isotherms).
15. Project presentations. Course review, example problem solving, additional topics of interest.
16. Final exam; 2 consecutive lecture hours written exam or individual 60 minute slots oral exam.

Consultation Place/Time (English) : office D-309 (Gwanggyo campus, GSCST), Wednesdays 10-12 during the course period.

Welcome !

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