Nanoconfinement Effects on Intermolecular Forces Observed via Dewetting

While intermolecular forces like van der Waals (vdW) can be tuned by varying thickness in multi-layer polymer films, nanoconfinement effects are less understood. Dewetting patterns are examined in a tri-layer system: bottom bulk polystyrene (PS, 450 nm), middle poly(methyl methacrylate) (PMMA, 15-95 nm), and top dewetting PS (10 nm). The top PS dewetting depends on underneath PMMA thickness, deviating from conventional vdW arguments. In contrast, nanoconfinement-driven effective Hamaker constant captures this behavior, manifesting nanoconfinement effects on intermolecular interactions.