title: Layer-by-layer assembly of imogolite nanotubes and polyelectrolytes into core-shell particles and their conversion to hierarchically porous spheres.
abstract: Core-shell particles were prepared by the layer-by-layer (LbL) assembly of imogolite (IMO) nanotubes and poly(sodium 4-styrenesulfonate) (PSS) on polystyrene particles (diameter: 800 nm) coated preliminarily with poly(diallyldimethylammonium chloride) (PDDA). PSS and imogolite were alternately adsorbed on the particles to form core-shell particles with one to three bilayers of PSS/IMO. Macroporous hollow spheres were formed by removing polystyrene cores via heat treatment or extraction when the number of bilayers was 2 or 3. The sample formed by extraction (the number of bilayer was 3) showed only macroporosity and PSS remained in the shell, whereas the heat-treated sample showed hierarchical micro- and macroporosities. When the diameter of polystyrene particles decreased from 800 nm to 300 or 100 nm, hollow spheres were deformed because of the increase in the relative length of imogolite nanotubes against the size of polystyrene particles. Imogolite is a promising building block of hierarchically porous materials with core-shell morphologies using LbL assembly.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kuroda
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan; Kagami Memorial Laboratory for Materials Science and Technology, Waseda University, Nishi-waseda 2-8-26, Shinjuku-ku, Tokyo 169-0051, Japan; CREST, Japan Science and Technology Agency, Honcho 4-1-8, Kawaguchi-shi, Saitama 332-0012, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kuroda
keywords: colloidal templating; core-shell particles; hierarchically porous materials; hollow spheres; imogolite; layer-by-layer; nanotubes