The nanomorphology of sterically stabilized polypyrrole-palladium nanocomposite particles synthesized by aqueous chemical oxidative dispersion polymerization has been extensively characterized by transmission electron microscopy (TEM) and smallangle X-ray scattering (SAXS). High-resolution TEM studies revealed that non-spherical nanocomposite particles were produced with a Heywood diameter of B30 nm and also confirmed the existence of palladium nanocrystals with a diameter of 5.4 nm within the particles. SAXS studies on aqueous dispersions of the nanocomposite particles confirmed good colloidal stability and revealed that the average diameters of the Pd nanoparticles and the nanocomposite particles were 5.0 and 23 nm, respectively, which agreed well with the TEM results. Furthermore, their size distributions were revealed by the SAXS technique. The hydrodynamic diameter of the nanocomposite particles determined by dynamic light scattering was larger than those determined by TEM and SAXS, possibly owing to the presence of a hydrated colloidal stabilizer layer on the particle surfaces.

No abstract

No abstract

Aqueous chemical oxidative dispersion polymerizations of pyrrole using PdCl 2 oxidant were conducted using sodium poly(styrene sulfonate)-block-poly(N-isopropyl acrylamide) as a colloidal stabilizer in order to synthesize thermo-responsive polypyrrole-palladium (PPy-Pd) nanocomposite particles in one step. PPy-Pd nanocomposite particles with number-average diameters of approximately 20 nm were successfully obtained as colloidally stable aqueous dispersions, which were stable at least for 6 months. The resulting nanocomposite particles showed themo-responsive flocculation behavior in aqueous media in the presence of additional salts, which screen surface charge of the nanocomposite particles.

A 3-dimensional porous material prepared by transferring a sponge structure of a biomineral is coated by nickel via aqueous electroless plating.