Entropic and Enthalpic Surface Segregation from Blends of Branched and Linear Polymers

The surface segregation from blends of branched and linear polymers is investigated using Monte Carlo simulation. It is found that in the athermal system an entropic segregation is possible which favors the linear polymers at the surfaces. When an attraction between the polymer beads is introduced the branched polymers are found preferentially at the surface. The simulations provide a simple explanation of recent experimental observations on polyolefin materials in terms of enthalpic effects, but this suggests that the segregation behavior observed in experiments is not universal but should depend on details of fluid-fluid and fluid-surface interactions.