title: Partitioning of Laponite Clay Platelets in Pickering Emulsion Polymerization.
abstract: Partitioning of laponite disklike clay platelets between polymer particles and bulk aqueous phase was investigated in Pickering surfactant-free emulsion polymerization of styrene. Adsorption of laponite clay platelets plays an important role in the stabilization of this system, influencing the particle size and the number of particles, and, hence, the reaction rate. Adsorption isotherms show that, while the laponite clay platelets are almost fully exfoliated in water, they form multilayers on the surface of the polymer particles by the end of polymerization, as confirmed by transmission electron microscopy (TEM). This observation is supported by quartz crystal microbalance, conductivity, and TEM measurements, which reveal interactions between the clay and polystyrene, as a function of the ionic strength. The strong adsorption of clay platelets leaves a low residual concentration in the aqueous phase that cannot cause further nucleation of polymer particles, as demonstrated during seeded emulsion polymerization experiments in the presence of a high excess of clay. A Brunauer-Emmett-Teller (BET)-type model for laponite adsorption on polystyrene particles matches the adsorption isotherms.
authors.affiliation: Université de Lyon, Univ. Lyon 1 , CNRS, UMR 5007, Laboratoire d'Automatique et de Génie des Procédés (LAGEP), 43 Bd du 11 Nov. 1918, 69622 Villeurbanne, France.
authors.forename: Barthélémy
authors.initials: B
authors.lastname: Brunier
authors.affiliation: Université de Lyon, Univ. Lyon 1 , CNRS, UMR 5007, Laboratoire d'Automatique et de Génie des Procédés (LAGEP), 43 Bd du 11 Nov. 1918, 69622 Villeurbanne, France.
authors.forename: Nida
authors.initials: N
authors.lastname: Sheibat-Othman
authors.affiliation: Université de Lyon, Univ. Lyon 1 , CNRS, UMR 5007, Laboratoire d'Automatique et de Génie des Procédés (LAGEP), 43 Bd du 11 Nov. 1918, 69622 Villeurbanne, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Chevalier
authors.affiliation: Université de Lyon, Univ. Lyon 1 , CPE Lyon, CNRS, UMR 5265, Laboratoire de Chimie, Catalyse, Polymères et Procédés (C2P2), LCPP Group, 43 Bd du 11 Nov. 1918, 69616 Villeurbanne, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Bourgeat-Lami