Search for dissertations about: "synthesis silica"

Showing result 1 - 5 of 100 swedish dissertations containing the words synthesis silica.

  2. 1. Mesoporous Silica Formed with Triblock Copolymers

    Author : Katarina Flodström; Fysikalisk kemi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fysikalisk kemi; 1H NMR; TEM; SAXS; in situ; mechanism of formation; cubic Ia3d; cubic Im3m; Mesoporous; synthesis; Pluronic; SBA-16; SBA-15; hexagonal p6mm; synchrotron SAXS; Physical chemistry; amphiphilic polymers; silica;

    Abstract : The formation of highly ordered mesoporous silica materials, using PEO-PPO-PEO amphiphilic triblock copolymers (so-called Pluronics) as structure directing agents, has been studied. The materials are formed through the addition of a silica source to a polymer solution of low concentration (2.5 wt ) under acidic conditions. READ MORE

  4. 2. 3D Magnetic Photonic Crystals : Synthesis and Characterization

    Author : Mei Fang; K.Venkat Rao; Lyubov Belova; Rajeev Ahuja; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; magnetic photonic crystals; photonic band gaps; Fe3O4 nanoparticles; silica; Optical physics; Optisk fysik; Materials science; Teknisk materialvetenskap;

    Abstract : This thesis presents the synthesis methods and the characterizations of magnetic Fe3O4 nanoparticles, silica spheres with Fe3O4 nanoparticles embedded, and three dimensional magnetic photonic crystals (MPCs) prepared from the spheres. The structure, material composition, magnetic and optical properties, photonic band gaps (PBGs), as well as how these properties depend on the concentration of the magnetic nanoparticles, are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), superconducting quantum interference device (SQUID), Faraday rotation (FR) and optical spectrophotometers. READ MORE

  5. 3. Colloidal suspensions of mesostructured silica

    Author : Andreas Berggren; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; formation mechanism; non-ionic surfactants; silica; inorganic silica; colloidal suspension; control of particle size;

    Abstract : Mesoporous silica is a porous material with walls made of silica and pores in the size range of 2-50 nm. Since the silica most often is amorphous, the material lacks short range order but the pores may be arranged in different structures generating a long-range order. READ MORE

  6. 4. Nanostructured Ceramics - Synthesis and Understanding

    Author : Farnaz Ghajeri; Wei Xia; Freddy Kleitz; Uppsala universitet; []
    Keywords : Material Science; Nanoporouse Silica; Calcium Phosphate; Synthesis; Characterization; Adsorption; Teknisk fysik med inriktning mot materialvetenskap; Engineering Science with specialization in Materials Science;

    Abstract : During the last years, nanostructured ceramics have been favored for use in the industry due to their beneficial properties. For example, calcium phosphate ceramics with their biocompatible and bioactive characteristics are beneficial in biomedicine. READ MORE

  7. 5. Synthesis and Characterization of Functionalized Silica Mesoporous Crystals : Cationic Surfactant and Co-structure Directing Agent System

    Author : Lu Han; Osamu Terasaki; Viveka Alfredsson; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mesoporous silica; Template synthesis; Functionalization; Electron microscopy; Defects; Crystal growth; Catalysis; Inorganic chemistry; Oorganisk kemi; Structural Chemistry; strukturkemi;

    Abstract : This dissertation has been focused on the synthesis and characterization of novel functionalized silica mesoporous crystals by using cationic surfactant and co–structure directing agents (CSDA), the central concept of the synthesis method is to build proper organic/inorganic interactions by introducing CSDA into the synthesis system. By using cationic surfactant as template and anionic CSDA, carboxylic group functionalized mesoporous silicas were successfully synthesized. READ MORE