Soft matter under osmotic stress

In this article, we will show that the osmotic stress method can be successfully applied to study the thermodynamics of self-assembly phenomena in soft matter systems, such as biopolymer liquid crystals, surfactant and lipid mesophases, and polyelectrolyte–surfactant complexes. We will give two examples to that effect. Firstly, we will present intercolumnar force measurements between cylindrical surfactant micelles in solid-state polyelectrolyte–surfactant complexes as a function of ionic strength. Secondly, we will present measurements of the DNA cholesteric spherulite structure and pitch as a function of osmotic pressure in an effort to evaluate the chiral contribution to the interaction between DNA molecules.