Spreading of Ultrathin Polymer Films on Nanotextured Substrates Using Molecular Dynamics

Brooklyn Noble, University of Utah

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As surface effects become increasingly significant on the nanoscale, an understanding of ultrathin polymer-based liquid films becomes increasingly valuable. However, while crucial to the design of complex nanoscale systems, the physical mechanisms that govern spreading of ultrathin polymer films over nanoscale features are not well understood. We use molecular dynamics simulations to quantify the manner in which a polymer droplet advances on various textured substrates as a function of polymer length, functional chemical groups and substrate texture feature geometries. We show that a polymer film can advance omnidirectionally or unidirectionally, depending on the substrate texture geometry and polymer properties. In some cases, we observe preferential spreading and ordering of the polymer film along substrate grooves and explain this phenomenon in terms of energy potentials created by the substrate that superimpose to strongly attract polymer to the grooves. This research aims to provide a fundamental understanding of ultrathin polymer film spreading on textured substrates to enhance performance in such applications as nanoelectromechanical systems, high-resolution molding, antibiofouling coatings, nanofluidic devices and self-healing lubricating films, among many others.

Abstract Author(s): Brooklyn Noble