the intrinsic Helmholtz free energy functional can be derived from Wertheim’s TPTl.
A review of the DFTs based on TPTl is given in chapter 3 of this dissertation. As
will be discussed in this chapter, these theories are in general not applicable to a
range of inhomogeneous polymer systems. For example, the DFT by Tripathi and
Chapman [60] is not applicable to heteropolymers, or the DFT by Yu and Wu [61]
cannot be applied to study the lamellar microstructures in bulk copolymer melts.
Hence, the second specific objective of this research is the development of
a DFT based on TPTl which in general can be applied to a range of in-
homogeneous polymeric systems, and demonstrate few of its applications.
1.2 Basis: Wertheim’s first order thermodynamic
perturbation theory for associating fluids
Wertheim [26, 27, 28, 29] proposed a first order perturbation theory (TPTl) for
hydrogen-bonding atomic fluids. The molecules of the hydrogen-bonding/associating
fluid are modeled as hard spheres with off-centered, short-ranged and highly direc-
tional associating sites on them, as shown in fig. 1.3. The theory was initially de-
veloped for molecules with one associating site, and later generalized to account for
the presence of any number of associating sites on the molecules. Chapman [58] ex-
tended Wertheim’s TPTl to mixtures of associating fluids, by introducing a simpler
notation. A brief background of TPTl is presented here using his notation.
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