Surfaces, Interfaces, Colloids

This course presents the concepts, foundations and orders of magnitude of the physics and physical chemistry of interfaces, which govern the mesoscopic scale of matter, and ultimately determine the behavior and properties of everyday objects: soil, milk, cheese, paints, inks, cosmetics, adhesives, lubricants, etc., as well as numerous technological processes and biological cells and membranes.

Understand the microscopic physical origin of colloidal interactions and be able to evaluate their intensities and ranges in relation to thermal agitation energy: for example, know how to calculate the van der Waals interaction energy between objects of simple geometric shapes, or the range of interactions between charged surfaces in water as a function of ionic strength.

- Know how to characterize a colloidal state: nature of dispersion, specific surface area, sedimentation length, diffusion coefficient, etc.

- Correctly estimate the numerical values of the various physical quantities relevant to the mesoscopic scale and know how to express them in units adapted to this scale.

- Know the different types of surface-active molecules and how they self-assemble: calculate a critical micellar concentration and know how to characterize it experimentally.

- Solve simple exercises relating to mooring statics.

Basic knowledge of general physics (thermodynamics, electrostatics, forces, energy, rudiments of quantum mechanics), thermochemistry, and mastery of basic mathematical tools for physics (derivatives, integrals, limited developments, cylindrical and spherical coordinates).

Final examination

The colloidal state: description, time, energy and length scales

Intermolecular interactions: covalent interactions, Coulomb interactions, dipolar interactions, selective interactions

Van de Waals interaction between colloids

Electrostatic forces between surfaces in liquids.

Polymer-mediated steric forces

Colloidal stability: DLVO theory. Coagulation kinetics.

Physical chemistry of self-assembly and surfactants

Wetting phenomena: surface and interfacial tension, wetting criterion, spreading parameter, capillary length, Young-Dupré's Law, Laplace's Law, Jurin's Law, tensiometry.

Chemical equilibria and free enthalpy

Acid-base, redox, solubility and complexation equilibria.

Preparation of colloidal suspensions ?