title: Structure, wrinkling, and reversibility of Langmuir monolayers of gold nanoparticles.
abstract: The assembly of nanoparticles into large, two-dimensional structures provides a route for the exploration of collective phenomena among mesoscopic building blocks. We characterize the structure of Langmuir monolayers of dodecanethiol-ligated gold nanoparticles with in situ optical microscopy and X-ray scattering. The interparticle spacing increases with thiol concentration and does not depend on surface pressure. The correlation lengths of the Langmuir monolayer crystalline domains are on the order of five to six particle diameters. Further compression of the monolayers causes wrinkling; however, we find that wrinkled monolayers with excess thiol can relax to an unwrinkled state following a reduction of surface pressure. A theoretical model based on van der Waals attraction and tunable steric repulsion is adopted to explain this reversibility.
authors.affiliation: The Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Schultz
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Lin
authors.forename: Dongxu
authors.initials: D
authors.lastname: Li
authors.forename: Jeff
authors.initials: J
authors.lastname: Gebhardt
authors.forename: Mati
authors.initials: M
authors.lastname: Meron
authors.forename: P James
authors.initials: PJ
authors.lastname: Viccaro
authors.forename: Binhua
authors.initials: B
authors.lastname: Lin