Polymer Knots in Thin Slit-Confined Melts: Thickness Dependence, Local Effects, and Stiffness

We study how confinement affects topology and conformations in flexible and semiflexible slit-confined polymer melts of varying thickness h. The knotting probability exhibits a maximum at intermediate thicknesses near the bulk radius of gyration h ≈ Rg,bulk, vanishes at small h, and approaches bulk values for large h. While knotting is enhanced close to boundaries, the entanglement length increases monotonically and conformations become increasingly flattened. A layer-resolved analysis of structural and topological properties allows us to reconstruct the explicit thickness dependencies by integrating layer-resolved properties of a thick slit.