Interfacial properties play an important role in many industrial processes, such as adhesion, polymer coating and thin films, paints, separations, catalysis, wettability, and emulsions. This has motivated studies of complex macromolecular systems (hydrocarbons, proteins, polymers) in confined geometries, and at solid-fluid and fluid-fluid interfaces. As properties of complex chemical systems are being tailored at the nanoscale, a molecular level understanding of the interplay between interfacial properties, fluid structure, and macroscopic properties of the material is necessary. Experimental investigation of interfacial phenomena is hampered by the small scale of these systems, making it difficult to isolate what competing effects drive the fluid behavior and structure. Molecular simulations can operate on this level, but are computationally expensive, and thus are limited to small-to-moderate chain lengths. Consequently, substantial efforts have been directed towards developing a theory for structure and thermodynamics of inhomogeneous polymeric solutions and blends.

Interfacial-SAFT (iSAFT) is a recently developed density functional theory, based on Wertheim's thermodynamic perturbation theory for association, which is computationally simple and thermodynamically consistent in describing the phase behavior and microstructure of polymeric fluids in inhomogeneous environments. In this work, new results from iSAFT are presented. First the interfacial properties and structure of polymers near a colloidal particle are examined. Here the polymer/colloid size ratio is varied at multiple length scales at different polymer concentrations, and the effect of including attractions between solute and polymer are discussed. Furthermore, we take advantage of the theory's ability to explicitly account for molecular association (hydrogen bonding) and chain heterogeneity to study the fluid structure near surfaces for lipid or surfactant-like molecules and polymers exhibiting chain branching.