title: Development of experiment and theory to detect and predict ligand phase separation on silver nanoparticles.
abstract: MALDI mass-spectrometry measurements are combined with self-consistent mean-field (SCF) calculations to detect and predict ligand phase separation on Ag nanoparticles. The experimental and theoretical techniques complement each other by enabling quantification of the nearest-neighbor distribution of a ligand mixture in a monolayer shell. By tracking a characteristic metallic fragment family, analysis of a MALDI spectrum produces a frequency distribution corresponding to specific ligand patterning. Inherent to the SCF calculation is the enumeration of local interactions that dictate ligand assembly. Interweaving MALDI and SCF facilitates a comparison between the experimentally and theoretically derived frequency distributions as well as their deviation from a well-mixed state. Thus, we combine these techniques to detect and predict phase separation in monolayers that mix uniformly or experience varying degrees of de-mixing, including microphase separation and stripe formation. Definition of MALDI removed as this is a commonly recognized technique.
authors.affiliation: University of Virginia, Department of Chemical Engineering, Charlottesville, VA 22904 (USA).
authors.forename: Zachary
authors.initials: Z
authors.lastname: Farrell
authors.affiliation: University of Virginia, Department of Chemical Engineering, Charlottesville, VA 22904 (USA).
authors.forename: Steve
authors.initials: S
authors.lastname: Merz
authors.affiliation: University of Virginia, Department of Chemistry, McCormick Road, Charlottesville, VA 22904 (USA).
authors.forename: Jon
authors.initials: J
authors.lastname: Seager
authors.affiliation: University of Virginia, Department of Chemical Engineering, Charlottesville, VA 22904 (USA).
authors.forename: Caroline
authors.initials: C
authors.lastname: Dunn
authors.affiliation: University of Virginia, Department of Chemistry, McCormick Road, Charlottesville, VA 22904 (USA). sae6e@virginia.edu.
authors.forename: Sergei
authors.initials: S
authors.lastname: Egorov
authors.affiliation: University of Virginia, Department of Chemical Engineering, Charlottesville, VA 22904 (USA). dlg9s@virginia.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Green
keywords: mass spectrometry; nanoparticles; nanotechnology; self-assembly; statistical thermodynamics