Competing interactions in arrested States of colloidal clays.
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.
Ruzicka
B
B
SOFT INFM-CNR and Dipartimento di Fisica, Sapienza Università di Roma, I-00185, Italy.
Zulian
L
L
Zaccarelli
E
E
Angelini
R
R
Sztucki
M
M
Moussaïd
A
A
Ruocco
G
G