Clay-polymer dispersions in aqueous solutions are of great interest due to their industrial applications and intriguing physical properties. Aqueous solutions of bare Laponite particles age spontaneously, from an ergodic to a non-ergodic state, in a time varying from hours to months depending on Laponite concentration. When a polymer species, such as polyethylene oxide (PEO), is added to the solution, it weakly adsorbs on clay particle surfaces modifying the effective interaction potential between Laponite particles. A dynamic light-scattering study was performed to investigate the effect of polymer on the aging dynamics of the system by varying the polymer concentration at a fixed polymer molecular weight (M(w) = 200,000 g/mol). The results show that arresting phenomena between clay particles are hindered when PEO is added and, thus, a slowing of the aging dynamics with increasing PEO concentration is observed. A possible mechanism is progressive coverage of the clay surface by polymers, which grow with increasing PEO concentration.
Influence of an adsorbing polymer on the aging dynamics of Laponite clay suspensions / L., Zulian; B., Ruzicka; Ruocco, Giancarlo. - In: PHILOSOPHICAL MAGAZINE. - ISSN 1478-6435. - 88:33-35(2008), pp. 4213-4221. (Intervento presentato al convegno 11th International Workshop on Complex Systems tenutosi a Andalo, ITALY nel MAR 17-20, 2008) [10.1080/14786430802581876].
Influence of an adsorbing polymer on the aging dynamics of Laponite clay suspensions
RUOCCO, Giancarlo
2008
Abstract
Clay-polymer dispersions in aqueous solutions are of great interest due to their industrial applications and intriguing physical properties. Aqueous solutions of bare Laponite particles age spontaneously, from an ergodic to a non-ergodic state, in a time varying from hours to months depending on Laponite concentration. When a polymer species, such as polyethylene oxide (PEO), is added to the solution, it weakly adsorbs on clay particle surfaces modifying the effective interaction potential between Laponite particles. A dynamic light-scattering study was performed to investigate the effect of polymer on the aging dynamics of the system by varying the polymer concentration at a fixed polymer molecular weight (M(w) = 200,000 g/mol). The results show that arresting phenomena between clay particles are hindered when PEO is added and, thus, a slowing of the aging dynamics with increasing PEO concentration is observed. A possible mechanism is progressive coverage of the clay surface by polymers, which grow with increasing PEO concentration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.