Monolayer Packing, Dehydration, and Ink-Binding Dynamics at the Molecular Printboard

Abstract

Gold-bound self-assembled monolayers (SAMs) terminating in -cyclodextrin ( -CD) cavities provide a highlyordered surface array of hydrophobic binding pockets and so are used as “molecular printboards” fornanopatterning applications. The present work complements ongoing nanoscale experiments by providingthe atom-scale structure, dynamics, and energetics of the printboard, which may aid the design of functionalplatforms for nanotechnology. We use fully atomistic molecular dynamics (MD) computer simulations toprobe the printboard lattice constant, height, steric packing, hydrophobicity, and ink-binding properties as afunction of gold- -CD “linker” molecule and degree of binding to gold. The simulations reveal the stabilizationassociated with the experimentally observed surface lattice constant of ∼2 nm, alkanethioether linkers, andpartial unbinding from gold. Additional ink-binding simulations indicate that multivalent ink molecules canoffset disordering in the more loosely packed alkanethiol-linked printboard, with the attendant steric penaltysimilar in magnitude to the favorable multivalent ink: -CD complexation.