title: Effect of MacroRAFT Copolymer Adsorption on the Colloidal Stability of Layered Double Hydroxide Nanoparticles.
abstract: The colloidal behavior of layered double hydroxide nanoparticles containing Mg(2+) and Al(3+) ions as intralayer cations and nitrates as counterions (MgAl-NO3-LDH) was studied in the presence of a short statistical copolymer of acrylic acid (AA) and butyl acrylate (BA) terminated with 4-cyano-4-thiothiopropylsulfanyl pentanoic acid (CTPPA) (P(AA7.5-stat-BA7.5)-CTPPA) synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization. Surface charge properties and aggregation of the particles were investigated by electrophoresis and dynamic light scattering (DLS), respectively. The negatively charged P(AA7.5-stat-BA7.5)-CTPPA adsorbed strongly on the oppositely charged particles, leading to charge neutralization at the isoelectric point (IEP) and charge reversal at higher copolymer concentrations. The dispersions were unstable, i.e., fast aggregation of the MgAl-NO3-LDH occurred near the IEP while high stability was achieved at higher P(AA7.5-stat-BA7.5)-CTPPA concentrations. Atomic force (AFM) and transmission electron (TEM) microscopy imaging revealed that the platelets preferentially adopted a face-to-face orientation in the aggregates. While the stability of the bare particles was very sensitive to ionic strength, the P(AA7.5-stat-BA7.5)-CTPPA copolymer-coated particles were extremely stable even at high salt levels. Accordingly, the limited colloidal stability of bare MgAl-NO3-LDH dispersions was significantly improved by adding an appropriate amount of P(AA7.5-stat-BA7.5)-CTPPA to the suspension.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva , 30 Quai Ernest-Ansermet, CH-1205 Geneva, Switzerland.
authors.forename: Marko
authors.initials: M
authors.lastname: Pavlovic
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva , 30 Quai Ernest-Ansermet, CH-1205 Geneva, Switzerland.
authors.forename: Monika
authors.initials: M
authors.lastname: Adok-Sipiczki
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva , 30 Quai Ernest-Ansermet, CH-1205 Geneva, Switzerland.|Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, Université de Pau et des Pays de l'Adour, 2 Avenue du Président Angot, F-64000 Pau, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Nardin
authors.affiliation: University of Lyon, Univ. Lyon 1, CPE Lyon, CNRS, UMR 5265, Laboratoire de Chimie, Catalyse, Polymères et Procédés (C2P2), LCPP group, 43, Blvd du 11 Novembre 1918, F-69616 Villeurbanne, France.|Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10446, F-63000 Clermont-Ferrand, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Pearson
authors.affiliation: University of Lyon, Univ. Lyon 1, CPE Lyon, CNRS, UMR 5265, Laboratoire de Chimie, Catalyse, Polymères et Procédés (C2P2), LCPP group, 43, Blvd du 11 Novembre 1918, F-69616 Villeurbanne, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Bourgeat-Lami
authors.affiliation: Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10446, F-63000 Clermont-Ferrand, France.|CNRS, UMR 6296, F-63178 Aubière, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Prevot
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva , 30 Quai Ernest-Ansermet, CH-1205 Geneva, Switzerland.
authors.forename: Istvan
authors.initials: I
authors.lastname: Szilagyi
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000327:Adsorption; D003102:Colloids; D006878:Hydroxides / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000179:Acrylates; D003102:Colloids; D006878:Hydroxides; D011108:Polymers; C032490:n-butyl acrylate; C036658:acrylic acid