title: Silica coating and photochemical properties of layered double hydroxide/4,4'-diaminostilbene-2,2'-disulfonic acid nanocomposite.
abstract: Organic ultraviolet (UV) rays absorbents have been used as sunscreen materials, but they may pose a safety problem when used at high concentration. In order to prevent direct contact of organic UV rays absorbent to the human skin, a typical organic UV-absorbent, 4,4(')-diaminostilbene-2,2(')-disulfonic acid (DASDSA), was intercalated into Zn(2)Al layered double hydroxide (Zn(2)Al-LDH) by coprecipitation reaction. However, deintercalation of DASDSA from Zn(2)Al-LDH, by the anion exchange reaction with carbonate ion, was observed. Therefore, Zn(2)Al-LDH/DASDSA was directly coated with silica by means of polymerization technique based on the Stöber method. Silica coating effectively depressed the deintercalation of DASDSA from Zn(2)Al-LDH. The amorphous silica was confirmed by XRD, SEM, TEM and FT-IR. The deintercalation behaviors as well as UV-shielding properties were investigated for coated particles.
authors: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
authors: Ahmed Mohamed
authors: AM
authors: El-Toni
authors: Shu
authors: S
authors: Yin
authors: Tsugio
authors: T
authors: Sato
mesh_terms: D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D006868:Hydrolysis; D006878:Hydroxides / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010777:Photochemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013267:Stilbenes / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D006878:Hydroxides; D013267:Stilbenes; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C039607:4,4'-diaminostilbene; D012822:Silicon Dioxide; C025953:amsonic acid; C031356:hydroxide ion