Chapter 8
Statistical Thermodynamics of Polymer
Solutions
8.1 Polymer-Based Multi-Component Systems
Polymer-based multi-component systems can be classified into two categories: one
is a miscible system, in which polymers are homogeneously mixed with other
molecules; the other one is a composite system, in which polymers are not mixed
with other molecules, except at interfaces.
Polymer-based composite systems normally consist of a continuous matrix and a
dispersed phase like particles. Polymers are the great candidates as matrix
materials. In the case where the matrix is an inorganic material and the particles
are polymeric materials, such a composite system is commonly regarded as an
organic/inorganic hybrid. In the composite system, the dispersed particles may have
a wide range of shapes and sizes, and play a dominant role in the functional
enhancement of the matrix, although never mixed with the matrix in their thermal
history, such as carbon black, liquid crystal droplets, high-strength fibers and their
textiles, inorganic fillers, carbon nanotubes and graphines. The interface properties
of composites are one of central issues in the investigation of high performance
polymer composites. However, we hereby focus our attention mainly on the
polymer-based miscible systems.
The polymer-based miscible systems can be either intermolecular mixtures, for
instance polymer solutions and blends, or intramolecular mixtures, such as block
copolymers, star-shape multi-arm copolymers, grafted copolymers, random
copolymers, and gradient copolymers with a composition gradient from one chain
end to the other. Polymer-based miscible systems can phase separate into
segregated phases with stable interfaces, or crystallize into crystalline ordered
phases. In other words, there are two types of phase transitions, phase separation
and crystallization. Under proper thermodynamic conditions, two phase transitions
may occur simultaneously. The interplay of these two transitions will dictate the
final morphology of the system. In the following, we will choose polymer solutions
as typical examples to introduce the polymer-based miscible systems.
W. Hu,Polymer Physics, DOI 10.1007/978-3-7091-0670-9_8,
#Springer-Verlag Wien 2013
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