title: Nanoparticles at liquid interfaces: rotational dynamics and angular locking.
abstract: Nanoparticles with different surface morphologies that straddle the interface between two immiscible liquids are studied via molecular dynamics simulations. The methodology employed allows us to compute the interfacial free energy at different angular orientations of the nanoparticle. Due to their atomistic nature, the studied nanoparticles present both microscale and macroscale geometrical features and cannot be accurately modeled as a perfectly smooth body (e.g., spheres and cylinders). Under certain physical conditions, microscale features can produce free energy barriers that are much larger than the thermal energy of the surrounding media. The presence of these energy barriers can effectively "lock" the particle at specific angular orientations with respect to the liquid-liquid interface. This work provides new insights on the rotational dynamics of Brownian particles at liquid interfaces and suggests possible strategies to exploit the effects of microscale features with given geometric characteristics.
authors.affiliation: Department of Chemical Engineering, City College of City University of New York, New York, New York 10031, USA.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Razavi
authors.affiliation: Department of Chemical Engineering, City College of City University of New York, New York, New York 10031, USA.
authors.forename: Ilona
authors.initials: I
authors.lastname: Kretzschmar
authors.affiliation: Department of Physics and The Benjamin Levich Institute for Physico-chemical Hydrodynamics, City College of City University of New York, New York, New York 10031, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Koplik
authors.affiliation: Department of Mechanical Engineering, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Colosqui
mesh_terms: D056004:Molecular Dynamics Simulation; D053758:Nanoparticles / Q000737:chemistry*; D012399:Rotation; D013499:Surface Properties; D013816:Thermodynamics