ABSTRACT
As the size and shape of a polymer chain are of considerable interest to the polymer scientist, it is useful to know how these factors can be assessed. Much of the information can be derived from studies of dilute solutions; absolute measurement of polymer chain size can be obtained from light scattering, when the polymer is large compared with the wavelength of the incident light. Sometimes, the absolute measurement cannot be used, but the size can be deduced indirectly from viscosity measurements, which are related to the volume occupied by the chain in solution. Armed with this information, we must now determine how meaningful it is, and for this a clearer understanding of the factors governing the shape of the polymer is required. We will confine ourselves to models of the random coil, as this is usually believed to be most appropriate for synthetic polymers; other models — rods, disks, spheres, and spheroids — are also postulated but need not concern us at this level.
