STUDIES ON FABRICATION OF SUPRAPARTICLES USING REACTIVE POLYMERIC MICROSPHERES

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Monodisperse, reactive polymeric microspheres of about 0.2μ m in diameter, which have a high concentration of active ester group at their surfaces, were synthesized by emulsifier-free emulsion copolymeriztion of styrene with methacryloyloxyphenyldimethylsulfonium methysulfate. The fabrication of particle assemblies, supraparticles, from the reactive polymeric microspheres by two methods, adsorption and binding method, was investigated based on their cationic surface charges and high reactivitity towards primary amino groups, respectively, mainly at solid/liquid interface for glass plates. Using the adsorption method, stable particle monolayers were fabricated through dipping the glass plates into a relatively high concentration of the aqueous particle dispersion, latex, containing a low concentration of added salt, NaCl. For the system, the particle monolayers of a more densely packed structure were formed by repeating several times cycles of dipping the adsorbed particle layers into the aqueous solution of sodium dodecylsulfate and then the latex. On the other hand, using the binding method, the fabrication of particle monolayers with an approximately closest packed structure was accomplished by dipping the glass plate surface-aminated with silane coupling agent bearing primary amino group into a low concentration of latex containing a relatively high concentration of the added salt. Furthermore, the latex particles were found to be also adsorbed onto the glass plate hydrophobized with coupling agents having no primary amino groups and the adsorption was inhibited on adding cationic or nonionic surfactants into the latex. From the results obtained in the present studies, it was disclosed that the fabrication and the structure of particle monolayers at the surface of glass plate can be controlled by changing the latex concentration and the added salt concentration, the surface modification with silane coupling agents, and the addition of surfactants into the latex.