Implicit-Solvent Coarse-Grained Simulation with a Fluctuating Interface Reveals a Molecular Mechanism for Peptoid Monolayer Buckling

Peptoid polymers form extended two-dimensional nanostructures via an interface-mediated assembly process: the amphiphilic peptoids first adsorb to an air–water interface as a monolayer, then buckle and collapse into free-floating bilayer nanosheets when the interface is compressed. Here, we investigate the molecular mechanism of monolayer buckling by developing a method for incorporating interface fluctuations into an implicit-solvent coarse-grained model. Representing the interface with a triangular mesh controlled by surface tension and surfactant adsorption, we predict the direction of buckling for peptoids with a segregated arrangement of charged side chains and predict that peptoids with with an alternating charge pattern should buckle less easily than peptoids with a segregated charge pattern.