On the interdigitation of molecular brushes and solvation force upon adsorption of water in slit-like pores with grafted chains. Density functional approach

Abstract

We have explored adsorption of a single waterlike model in slitlike pores with walls chemically modified by tethered chains that form molecular brushes. Principal focus of the present study is in the evolution of the microscopic structure of fluid species and of a system of chain molecules upon adsorption. A density functional approach is used. Various projections of the vapor–liquid coexistence envelope, including brushes interdigitation coefficient, are obtained and discussed. We have discovered that the molecular brushes can shrink or “swell” upon phase transition in confined water dependent on the attraction between fluid molecules and chains segments. Trends of behavior of the solvation force between pore walls are investigated dependent on the parameters of the system. Particular attention is paid to the appearance of the effective attraction between pore walls.