title: Competing interactions in arrested States of colloidal clays.
abstract: Using experiments, theory and simulations, we show that the arrested state observed in a colloidal clay at high concentrations is stabilized by screened Coulomb repulsion (Wigner glass). Dilution experiments allow us to distinguish this disconnected state, which melts upon addition of water, from a low-concentration gel state, which does not melt. Theoretical modeling and simulations at high concentrations reproduce the measured small angle x-ray scattering static structure factors and confirm the long-range electrostatic nature of the arrested structure. These findings are attributed to the different time scales controlling the competing attractive and repulsive interactions.
authors.affiliation: SOFT INFM-CNR and Dipartimento di Fisica, Sapienza Università di Roma, I-00185, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Ruzicka
authors.forename: L
authors.initials: L
authors.lastname: Zulian
authors.forename: E
authors.initials: E
authors.lastname: Zaccarelli
authors.forename: R
authors.initials: R
authors.lastname: Angelini
authors.forename: M
authors.initials: M
authors.lastname: Sztucki
authors.forename: A
authors.initials: A
authors.lastname: Moussaïd
authors.forename: G
authors.initials: G
authors.lastname: Ruocco