dissertation.
4.4 Conclusions
A new density functional theory for inhomogeneous polymeric fluids has been
proposed. The theory is based on Wertheim’s first order thermodynamic perturba-
tion theory for associating fluids and is derived along similar lines as iSAFT [60].
The theory is generally applicable to mixtures of heteronuclear chains, eg. lipids,
copolymers, grafted polymers, polymer/colloid and polymer/nanoparticle systems.
The theory only requires the segment interaction potential and the bulk chemical
potential of the chain as input. For lipid melts near surfaces, the theory shows ex-
cellent agreement with the simulation results. For lipid solutions, solvent molecule is
modeled as a single spherical segment. Comparisons of the results from the theory
with results from molecular simulations demonstrate that this simple model efficiently
accounts for the effect of the solvent on the microstructure of lipids near the surface.
The theory is further applied to study the structure of a lipid bilayer. For copoly-
mers, the microstructures of thin films of block copolymers were studied using the
theory. The theory successfully captures the effect of copolymer „chain architecture,
and segment-segment and surface-segment interactions on the microstructure of these
systems and the results are in excellent agreement with the simulation results.
Appendix: Derivation of X3a and X3b for a linear chain of
‘m’ segments
108