title: Direct determination of the thermodynamics of polyelectrolyte complexation and implications thereof for electrostatic layer-by-layer assembly of multilayer films.
abstract: Interpolyelectrolyte complex (IPEC) formation between poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) has been studied over a range of ionic strengths by isothermal titration calorimetry (ITC), turbidity titration, and electrostatic layer-by-layer assembly (ELBL). The results indicate that IPEC formation of PSS/PAH in aqueous solution is predominantly entropy-driven. The thermodynamic parameters suggest the formation of different types of complexes and aggregates due to salt-induced conformational changes in the polyelectrolyte conformation. Differences in polyelectrolyte behavior in the different salt-concentration regimes are described in terms of changes in the Debye screening length of the polyelectrolytes. The relationship of the results to the effect of salt concentration on the assembly of polyelectrolyte multilayer films (PEMs) is discussed.
authors.affiliation: Biomedical Engineering, Physics, and Bionanosystems Engineering Laboratory, Louisiana Tech University, Ruston, Louisiana 71272, USA.
authors.forename: Satish
authors.initials: S
authors.lastname: Bharadwaj
authors.forename: Reza
authors.initials: R
authors.lastname: Montazeri
authors.forename: Donald T
authors.initials: DT
authors.lastname: Haynie
mesh_terms: D002152:Calorimetry, Differential Scanning; D011073:Polyamines / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D011073:Polyamines; D011137:Polystyrenes; C063994:polyallylamine; D012965:Sodium Chloride; C003321:polystyrene sulfonic acid