• Fully atomistic modeling of polymer molecule with more than a thousand atoms
is computationally intractable. Hence, the model polymer molecule is “coarse-
grained” so that groups of atoms are lumped into larger entities referred to as
“segments”. Although, this coarse-graining procedure may ignore the atomic
details of the polymer molecules, it must preserve their large-scale features, such
as chain connectivity, space-filling characteristics, and architecture.
• In a polymer/solvent system, as the difference in the molecular sizes of the
components increases, the miscibility gaps becomes highly symmetric, with the
critical points shifting towards lower mass fractions of polymer. This leads to
numerical complexities like convergence (due to very low polymer mass fraction
in the polymer-lean phase), while modeling these systems.
• Polymers are branched, with the branch points being regular or random, leading
to different chain architectures. These branches significantly affect the phase
behavior of polymer systems.
• In addition to branching, polymer chains can have functional groups, such as
polar groups in poly(ethylene-co-methacrylate) or hydrogen bonding groups in
poly(ethylene-co-acrylic acid).
• Polymer samples are often polydisperse in molecular weight, chain branch-
ing, and comonomer content (and therefore polarity and hydrogen-bonding
strength). Consequently, a polymer solution is de facto a multi-component