title: Ion distribution in multilayers of weak polyelectrolytes: A neutron reflectometry study.
abstract: Neutron reflectometry was used to determine the distribution of salt ions and water in thin poly(acrylic acid) and poly(allylamine hydrochloride) polyelectrolyte multilayers assembled with and without salt. Increasing salt concentration reverses the exclusion of water from the substrate region, eventually leading to an asymmetric segregation of water near the substrate at high salt concentration. The counterions were found to localize near the substrate in films that were either assembled with salt or were exposed to salt solutions. In addition, the capping layer of the film was found to greatly influence the counterion distribution in the multilayer.
authors.affiliation: Department of Chemistry, McGill University, Montreal H3A 2K6, Canada.
authors.forename: Oleh M
authors.initials: OM
authors.lastname: Tanchak
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Yager
authors.forename: Helmut
authors.initials: H
authors.lastname: Fritzsche
authors.forename: Thad
authors.initials: T
authors.lastname: Harroun
authors.forename: John
authors.initials: J
authors.lastname: Katsaras
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Barrett
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods; D016503:Drug Delivery Systems; D004573:Electrolytes; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D009502:Neutrons; D011073:Polyamines / Q000737:chemistry; D012492:Salts / Q000737:chemistry; D012997:Solvents; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D004573:Electrolytes; D007477:Ions; D011073:Polyamines; D012492:Salts; D012997:Solvents; D014867:Water; C063994:polyallylamine; C006903:carbopol 940