title: Manipulation of shell morphology of silicate spheres from structural evolution in a purely inorganic system.
abstract: We have investigated the structural transformation of solid silica spheres into various more complex spherical structures including flower-like, thick or thin nanosheet-shelled and porous shelled spheres. In the absence of organic additives, sodium salts contained in this inorganic reaction system apparently direct the silica dissolution and regrowth of dissolved silicate at the nanometer-scale, leading to the formation of a nanosheet network rather than solid aggregates. Subsequent removal of the salts by simple water washing results in voids in the siloxane network and a significant availability of surface silanol groups so that the resulting nanosheets and spheres composed of them possess large surface areas, pore volumes, and morphological flexibility, which can be varied by an applied stimulus. The results represent a rare example of the transformation of a simple silicate structure into a much more complex spherical structure involving a purely inorganic reaction system.
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan. JI.Qingmin@nims.go.jp.
authors.forename: Qingmin
authors.initials: Q
authors.lastname: Ji
authors.affiliation: Functional Geomaterials Group, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
authors.forename: Tatyana G
authors.initials: TG
authors.lastname: Terentyeva
authors.affiliation: High Field NMR Group, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Deguchi
authors.affiliation: High Field NMR Group, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Ohki
authors.affiliation: High Field NMR Group, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan.
authors.forename: Ma-Sataka
authors.initials: MS
authors.lastname: Tansho
authors.affiliation: High Field NMR Group, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Hill
authors.affiliation: WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan. ARIGA.Katsuhiko@nims.go.jp.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ariga
keywords: complex shell; hollow sphere; inorganic system; silica; template free