Large Scale Organisation of Flexible Polymers

The detailed shape and the correlations inside flexible coil polymers are discussed, with emphasis on (a) recent neutron scattering experiments and (b) theoretical developments based on a rigorous analogy between polymers and coupled spin systems (ferromagnets). For example, the size of a tagged (e.g. deuterated) molecule immersed in a semidilute solution of similar (hydrogenated) molecules has now been measured accurately, as a function of chain length, and polymer concentration. Remarkable laws have appeared – some of which go decidedly beyond the simple mean field analysis of Flory and Huggins. Extensions of these considerations to poor solvents (collapse or precipitation) will also be presented.