The colloidal domain is the domain of polymers, surfactants, liquid crystals, membranes, vesicles, emulsions, micelles and colloidal suspensions. This course deals with the physical properties of these objects whose general characteristic is to be ordered in a soft way with weak interactions. This soft order means that a small change in chemistry causes a significant change at the mesoscopic or macroscopic scale.    
 
This is where biology, physics and chemistry meet. Structures of biological molecules depend on the interactions between atomes and molecules, and the delicate interplay between energy and entropy, which results in the remarquable ability of biological systems to self-assemble and control their own replication. It is interesting to emphasize the concepts which bridge biology and the colloidal domain and this is one of the main purposes of these lectures.

This is an introductory course which assumes that the student possesses basic knowledge with essential principles of chemical structures, reactivity and bonding, basic concepts of molecular biology, and basic maths. The plan includes:
  •  General overview of the colloidal domain and of some structures in cell biology
  • Review of basic thermodynamics, thermodynamic potentials, minimum principles, entropy of mixing, osmosis,  Flory-Huggins theory;
  • Self-assembly of amphiphiles: Hydrophobic effects, critical micellar concentration, packing parameter, Tanford's free energy model, surface tension theory;
  • Basic probability theory, random walk physics and Brownian motion, polymer in good-solvent and self-avoidance effects;
  • Entropic elasticity of ideal chains, persistence length of a polymer, single molecule mechanics  for polymers, nucleic acid and proteins, physics for AFM and optical traps, force spectroscopy, how bio-polymers differ from usual polymers;
  • Basic statistical physics and Bolzmann-Gibbs distribution and examples of ion channels, electro-chemical cells and conformational protein regulation.     
  • Forces and structures: electrostatic forces, Debye length, van der Waals attraction, DLVO theory;
  • Bilayer and vesicles: The curvature energy problem;
  • Standard free energy changes: How to convert mechanical energy into work: Detailed balance, ATP hydrolysis, maltose transporter, ratchet problems for motor proteins and bio-polymerization (How to rectify Brownian motion);
  • Diffusion : Macroscopic theory. Einstein diffusion equation. Frap experiments. Diffusion reaction and chemical reaction, the diffusion limited rate limit. Introduction to the Turing instability.
  • Diffusion : Microscopic theory. Simple examples of the Fokker-Planck equation in a force field.