Introduction: Macromolecular systems in equilibrium

Abstract

The general theory of equilibrium and non-equilibrium properties of polymer solutions and melts appears to be derived from the universal models of long macromolecules which can be applied to any flexible macromolecule notwithstanding the nature of its internal chemical structure. Although many universal models are useful in the explanation of the behaviour of the polymeric system, the theory that will be described in this book is based on the coarse-grained model of a flexible macromolecule, the so-called, bead-and spring or subchain model. In the foundation of this model, one finds a simple idea to observe the dynamics of a set of representative points (beads, sites) along the macromolecule instead of observing the dynamics of all the atoms. It has been shown that each point can be considered as a Brownian particle, so the theory of Brownian motion can be applied to the motion of a macro molecule as a set of linear-connected beads. The large-scale or low-frequency properties of macromolecules and macromolecular systems can be universally described by this model, while the results do not depend on the arbitrary number of sites. In this chapter, the bead-and-spring model will be introduced and some properties of simple polymer systems in equilibrium are discussed. © Springer Science+Business Media B.V. 2010.