title: Molecular-scale observation of the surface of polystyrene particles by AFM.
abstract: The surface morphology of polystyrene particles prepared by soap-free emulsion polymerization was observed in situ using the tapping mode of an atomic force microscope (AFM). Here, the use of a cationic initiator enabled us to synthesize positively charged polystyrene, which then adsorbed electrostatically onto the negatively charged mica plate with molecular-scale smoothness. The following was found from AFM measurements in water. The surface of polystyrene particles changed from smooth to rough as the polymerization proceeded in the experimental condition, where the bulk generated tiny particles continuously, because of the heterocoagulation in the growth process between the newborn and tiny particles and the existing particles. However, it is easy to prepare the particles with smooth surfaces on the condition of rich monomers because the monomers in the bulk dissolve the polymers which form the surface morphology to be deformable and reduce the interfacial area.
authors.affiliation: Department of Chemical Engineering, Kyoto University-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan. tetsuya@cheme.kyoto-u.ac.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Fukushima
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kanda
authors.forename: Ko
authors.initials: K
authors.lastname: Higashitani
mesh_terms: D000327:Adsorption; D018625:Microscopy, Atomic Force / Q000379:methods*; D010316:Particle Size; D011137:Polystyrenes / Q000138:chemical synthesis / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D011137:Polystyrenes; D014867:Water