such as methane with m less than 2. A possible solution to this problem is to start
with a fused dimer as the reference fluid. Further developments include extending
SAFT-D to copolymers, and investigating the effect of polydispersity in chain length
and comonomer content on the phase behavior of these systems.
For inhomogeneous polymeric systems, a new density functional theory (DFT)
called modified iSAFT is developed. Treating the polyatomic system as a mixture
of associating spheres in limit of complete association, the free energy functional is
derived by extending TPTl. This allows one to write the free energy functional in
terms of the segment densities, leading to a segment-based DFT. Thus, the theory is
easier to implement and computationally cheaper than other DFTs based on molecu-
lar densities. Furthermore, in the limit of ideal polymer chains, modified iSAFT gives
the exact segment density profile and the equilibrium free energy of these ideal poly-
mer chains (in an external field) as a function of only the segment densities. The rigor
and general segment-based formulation of the theory makes it in general applicable to
a range of heteronuclear as well as branched (inhomogeneous) polymer systems with
advanced segment-segment and segment-surface interactions. The model is validated
for heteronuclear polymers by applying it to predict the adsorption of model lipids
and multi-block copolymers at a surface, and comparing the results with molecu-
lar simulations. For branched polymers, the validation is done by comparisons with
molecular simulation results for the adsorption of star polymers on a surface.
A preliminary calculation for the self-assembly of lipids in aqueous medium to form
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