Classes of model for comparison with experiment

The low-shear viscosity of polymer solutions is considered in Chapter 12. The major effort in the chapter is demonstrating the functional form of the dependence of on c and M. A large-concentration transition in the functional form of t](c) is found for some but certainly not all systems. We finally consider the behavior of the parameters obtained from an accurate functional description of t] c,M). 

Chapter 13 examines the dependence of viscoelastic behavior, including the storage and loss moduli and shear thinning, on solution properties. Historically, it has been difficult to obtain a simple description of the dependence of G and G on c, M, or other parameters. Traditional reduced-variable methods have been disappointing experimental results remained confusing. Chapter 13 presents a novel ansatz and set of functional forms that describe G ico), G ( w), and q K) accurately at all frequencies and shear rates, while reducing measurements to a very small number of parameters. These parameters are found to have simple dependences on c and M, reinforcing the belief that the ansatz description has a fundamental basis. 

Chapter 14 sketches nonlinear properties of polymer solutions, some classical and some quite modem. Strange behaviors can arise in polymer solutions because the normal stress differences are nonzero, i.e., the diagonal components of the pressure tensor can be unequal. Memory effect properties, such as stress and strain relaxations, and responses to imposing multiple strains, are noted. Finally we consider very recent developments in the study of nonlinear effects, such as shear banding and nonquiescent relaxation following imposition of a sudden strain. 

A summary chapter presents briefly what was done in each of the prior chapters. Results from different experimental properties are then united, showing how they are interrelated and drawing additional conclusions that would not have been obvious from a single experimental method. 

The approach here is to compare experimental measurements of transport coefficients with functional forms and parametric dependences predicted by models of polymer dynamics. There is a very large number of proposed models. Most models 

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