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Title: Synthesis of half-sphere/half-funnel-shaped silica structures by reagent localization and the role of water in shape control

Role of water and ammonium hydroxide is investigated in evolution of shape of silica structures in the polyvinylpyrrolidone-pentanol emulsion droplet system. Shape control of silica structures is demonstrated by localization of the reagents. A uniform dispersion of reagents provided straight silica rods, while localization of the reagents at the emulsion droplet periphery provided a new type of structures half sphere-half funnel. The absence of water in the initial stages prompted a different nucleation process for the structure growth compared to when water was present in the intial stages. Effect of effective water concentration appeared to be related to the ease of diffusion of silica percursor inside the emulsion droplet,i.e., the higher the water concentration, the lower the silica precursor diffusion. Additionally, mixing the reagents in different combinations before adding to the reaction mixture also affected the silica structure thickness, length, and shape.
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Chemistry - A European Journal
Additional Journal Information:
Journal Volume: 22; Journal Issue: 52; Journal ID: ISSN 0947-6539
ChemPubSoc Europe
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; silica structures; shape control; mechanism
OSTI Identifier: