ABSTRACT
This chapter contains one of the more diverse assortments of topics of any chapter in this volume.
In this chapter we discuss the viscosity of polymer solutions, the diffusion of polymer molecules,
the technique of dynamic light scattering, the phenomenon of hydrodynamic interaction, and the
separation and analysis of polymers by size exclusion chromatography (SEC). At first glance these
seem to be rather unrelated topics, but all are important to molecular weight determination in
solution. Furthermore, all share a crucial dependence on the spatial extent of the molecules. In
Chapter 8 we considered in detail how light scattering can provide a direct measurement of the
radius of gyration. In this chapter the measure of size turns out to be roughly proportional to, but
not numerically equal to, the radius of gyration. As the chapter heading suggests, we now consider
for the first time in the book the time-dependent properties of polymers and particularly the rate at
which polymer molecules move through a solvent. By emphasizing dilute solutions, the properties
of individual polymer molecules are highlighted; in Chapter 11 we will consider the dynamic
properties of more concentrated solutions and melts.
