title: Direct measurement of colloidal interactions between polyaniline surfaces in a UV-curable coating formulation: the effect of surface hydrophilicity/hydrophobicity and resin composition.
abstract: The interactions between polyaniline particles and polyaniline surfaces in polyester acrylate resin mixed with 1,6-hexanediol diacrylate monomer have been investigated using contact angle measurements and the atomic force microscopy colloidal probe technique. Polyaniline with different characteristics (hydrophilic and hydrophobic) were synthesized directly on spherical polystyrene particles of 10 μm in diameter. Surface forces were measured between core/shell structured polystyrene/polyaniline particles (and a pure polystyrene particle as reference) mounted on an atomic force microscope cantilever and a pressed pellet of either hydrophilic or hydrophobic polyaniline powders, in resins of various polymer:monomer ratios. A short-range purely repulsive interaction was observed between hydrophilic polyaniline (doped with phosphoric acid) surfaces in polyester acrylate resin. In contrast, interactions between hydrophobic polyaniline (doped with n-decyl phosphonic acid) were dominated by attractive forces, suggesting less compatibility and higher tendency for aggregation of these particles in liquid polyester acrylate compared to hydrophilic polyaniline. Both observations are in agreement with the conclusions from the interfacial energy studies performed by contact angle measurements.
authors.affiliation: School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology , Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden.
authors.forename: Shadi
authors.initials: S
authors.lastname: Jafarzadeh
authors.forename: Per M
authors.initials: PM
authors.lastname: Claesson
authors.forename: Jinshan
authors.initials: J
authors.lastname: Pan
authors.forename: Esben
authors.initials: E
authors.lastname: Thormann