Course Description
This course is an introduction to the fundamental physics underlying the field of interface science and colloidal phenomena. This course is designed to make students familiar with the molecular, mechanical and equilibrium description of interfaces, predominantly focusing on liquid interfaces and interfacial tension. Some key ideas related to the physics of wetting, contact angle, wetting regimes on patterned surfaces, their applications in oil recovery will be dealt with. Students shall also be acquainted with intriguing behaviour of surfactants, their preferential adsorption on interfaces and micelle formation. Concepts of thin film modelling, Maragnoni stresses will be dwelled upon. The course will also cover concepts of the electric double layer and the stability of colloidal suspensions based on the celebrated DLVO theory. Finally, an introduction to the field of active colloids and their applications shall be presented.
Course Content
- Introduction to the world of colloids and dominance of surface effects in such systems
- Interfacial Tension: Molecular, mechanical and thermodynamic origin.
- Wetting, contact angle, Young-Dupre Law, Wenzel and Cassie-Baxter wetting regimes.
- Surfactant systems: Adsorption on interfaces, Gibbs adsorption isotherm, micelle formation.
- Interfacial fluid dynamics: Thin films, Marangoni flow, Wetting-Dewetting of thin films.
- Brownian motion, Langevin dynamics, Fluctuation-Dissipation Theorem.
- Surface and electrical forces in colloidal dispersions.
- Electrical Double Layer (EDL): Helmholtz, Gouy-Chapman, Stern models for the EDL
- Stability of colloidal dispersions and DLVO theory.
- Active Colloids: Mechanisms of self-propulsion and models for microbial swimmers.