Soft matter under osmotic stress

In this article, we will show that the osmotic stress method can be success fully applied to study the thermodynamics of self-assembly phenomena in sof t matter systems, such as biopolymer liquid crystals, surfacrant and lipid mesophases, and polyelectrolyte - surfactant complexes. We will give two ex amples to that effect. Firstly, we will present intercolumnar force measure ments between cylindrical surfactant micelles in solid-state polyelectrolyt e-surfactant complexes as a function of ionic strength. Secondly, we will p resent measurements of the DNA cholesteric spherulite structure and pitch a s a function of osmotic pressure in an effort to evaluate the chiral contri bution to the interaction between DNA molecules. (C) 2001 Published by Else vier Science Ltd.