Solvent Effects on the Structure and Thermodynamics of Polymer Blends with Varying Architectures

Advances in polymer synthesis have unlocked a widening library of nonlinear polymer architectures, such as cyclic, star, hyperbranched, and bottlebrush polymers. Blends of these architectures exhibit interesting and complex physics, as entropic effects related to the interplay between chain ends and branch points can be leveraged to tune blend structure and properties such as chain entanglements, segregation to surfaces, rheology, and others. Further tunability in structure and properties can be achieved through solvent processing of these materials, as the presence of solvent alters polymer blend thermodynamics by screening interactions between polymer chains and between polymer and surfaces. Herein, we will explore the thermodynamic implications of the solvent processing of polymer blends of varying architecture (linear, cyclic, star, and bottlebrush) using molecular dynamics simulation and polymer reference interaction site model (PRISM) theory. We will first present our coarse-grained model for polymer blends swollen by solvents of varying quality. We will then describe the application of the above computational techniques to calculate, both in real and Fourier space, the total intermolecular pair correlation functions, direct pair correlation functions, and effective interactions between polymer(s) and solvent(s). In particular, we will show how both entropic and enthalpic effects play a role in how solvents tune structure and thermodynamics in blends of polymer architectures.