title: Colloidal stability of zwitterionic polymer-grafted gold nanoparticles in water.
abstract: We investigate the colloidal stability of gold nanoparticles (AuNPs) coated with zwitterionic sulfobetaine polymers in aqueous solution. Zwitterionic polymers with different molar masses, synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of N,N'-dimethyl(methacrylamido propyl)ammonium propanesulfonate (SPP) exhibit a well known Upper Critical Solution Temperature (UCST) in water, i.e., phase separate at low temperature. The colloidal stability of gold nanoparticles grafted with PSPP was studied as a function of the temperature. The effects of the molar mass of the grafted polymers, the salt concentration, and the presence of free polymer chains in solution were investigated. UV-vis spectroscopy and dynamic light scattering measurements show that whatever the molar mass of the grafted polymer, the nanoparticles never aggregate at low temperature in pure water. However, a reversible thermal-driven aggregation process of the gold nanoparticles is observed in presence of free polymer chains in solution and explained by a depletion process.
authors.affiliation: Sciences et Ingénierie de la Matière Molle, PSL Research University, ESPCI ParisTech, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7615, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Durand-Gasselin
authors.affiliation: Sciences et Ingénierie de la Matière Molle, PSL Research University, ESPCI ParisTech, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7615, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Régis
authors.initials: R
authors.lastname: Koerin
authors.affiliation: Laboratoire de Chimie des Polymères, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7610, 3 rue Galilée, 94200 Ivry, France.
authors.forename: Jutta
authors.initials: J
authors.lastname: Rieger
authors.affiliation: Laboratoire de Physique et Etudes des Matériaux, PSL Research University, ESPCI ParisTech, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 8213, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lequeux
authors.affiliation: Sciences et Ingénierie de la Matière Molle, PSL Research University, ESPCI ParisTech, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7615, 10 rue Vauquelin, 75231 Paris Cedex 05, France. Electronic address: nicolas.sanson@espci.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sanson
mesh_terms: D017738:Alkanesulfonic Acids / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009994:Osmolar Concentration; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D017738:Alkanesulfonic Acids; D003102:Colloids; D011108:Polymers; D014867:Water; C068559:propylsulfonic acid; D006046:Gold
keywords: Colloidal stability; Depletion; Nanoparticles; Zwitterion