Solvent quality influences surface structure of glassy polymer thin films after evaporation*

In this talk, we present the structural effects of treating a glassy polymer thin film with solvents of varying quality and subsequently evaporating the solvent. Molecular dynamics simulations are used to investigate both a monodisperse and a polydisperse film for poor to good solvent conditions, including the limit in which the polymer film
is fully dissolved. The dissolved polymer-solvent mixtures form a polymer-rich skin, in agreement with previous studies.
We find that for non-dissolved films, the surface width of the film after solvent evaporation is enhanced compared to the case without solvent. The increased surface width is preserved after solvent evaporation for both mono- and polydisperse films, due to the kinetic arrest of the surface structure. Our results show that it is important to take poor solvent effects into account for the surface morphology of already formed thin glassy films, an effect which is often neglected.