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Control of internal (2D and 3D hexagonal) mesostructure andparticle morphology of spherical mesoporous silica particlesusing the emulsion and solvent evaporation (ESE) method
2009 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 120, 359-367 p.Article in journal (Refereed) Published
Abstract [en]

In this study we demonstrate the opportunities controlling internal structure as well as exterior morphology of surfactant templated mesostructured materials through the newly developed emulsion and solvent evaporation (ESE) method. In particular, we consider the control of synthesis temperature and map the influence upon both internal structure and surface morphology of particles templated by the temperature sensitive Pluronic block copolymer F127. Furthermore, we vary compositions, by adding poly(propylene glycol) acting as a swelling agent, as well as by controlling the moisture content. Both of these are having an impact on the internal mesostructure as well as the pore size. Apart from probing internal structure by scattering techniques, the accessibility of the mesoscopic pores of these materials are investigated by measuring the adsorption of a cationic dye, Janus Green B, into the materials. This method shows that accessibility varies dramatically with internal structure.Further, by carefully controlling the moisture content when using the cationic surfactant C(16)TAB as template, a well ordered 3D hexagonal closed packed (P6(3)/mmc) material with large surface area as well as pore volume was prepared. This further indicates the versatility of the new preparation technique.

Place, publisher, year, edition, pages
2009. Vol. 120, 359-367 p.
Keyword [en]
ESE method; Mesoporous materials; Spherical particles; Expanded pores; Pluronic F127; C(16)TAB; Morphology control; Poly(propylene glycol); 3D hexagonal; P6(3)/mmc
National Category
Physical Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-10104DOI: 10.1016/j.micromeso.2008.12.002ISI: 000264971200025OAI: oai:DiVA.org:kth-10104DiVA: diva2:208654
Note
QC 20100811Available from: 2009-03-19 Created: 2009-03-19 Last updated: 2017-12-13Bibliographically approved
In thesis
1. Mesostructured particulate silica materials with tunable pore size: Synthesis, characterization and applications
Open this publication in new window or tab >>Mesostructured particulate silica materials with tunable pore size: Synthesis, characterization and applications
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Colloidal assemblies of surfactants and polymers in aqueous solutions have been used by human mankind for hundreds of years and they are of great importance in many of our technological processes, such as fabrication of soap and papermaking. Less than two decades ago the idea of using colloidal assemblies as templates of inorganic materials was borne. A new population of materials, referred to as surfactant templated materials, took form. These materials showed extraordinary properties such as monodisperse pore size distribution, large surface areas and pore volumes.

 

The main focus of this thesis has been on synthesis and functionalisation of spherical mesostructured silica particulate materials. In the first part of the work, mesostructured materials with expanded pores have been produced using a well established aerosol-based method as well as the newly developed emulsion and solvent evaporation (ESE) method. Increase in pore size was realized through using Pluronic block copolymer F127 together with a swelling agent poly(propylene glycol) as template. The influence of the swelling agent on pore size expansion was shown to have a roughly linear relationship. Furthermore, the impact of synthesis parameters on internal and exterior morphology has been investigated. Accessibility of the internal pore space, as well as the external surface roughness were shown to be highly dependent on synthesis temperature. Additionally, a very interesting well ordered 3D closed packed (P63/mmc) material was produced using the ionic surfactant C16TAB as template in the ESE method.

 

In the second part of the thesis work, mesoporous spheres with large pore size, having either hydrophilic or hydrophobic surface properties, were used as carriers of an enzyme, lipase. The enzymatic activity of lipase was increased onto the hydrophobic surface, compared to lipase immobilized into the hydrophilic support as well as for lipase free in solution. This effect was probably due to a combination of enhanced hydrophobic interactions preventing denaturation of the enzyme and interfacial activation of the enzyme.  This study generated an inorganic carrier material that is a promising candidate for biocatalysis applications. Additionally, mesoporous spheres were used as carriers of a model drug, Ibuprofen, to study the effect of polyelectrolyte multilayers on release properties. However, these layers were shown impermeable independent on pH and the substance was only released from uncoated particles.

Place, publisher, year, edition, pages
Stockholm: KTH, 2009. 70 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2009:8
Keyword
Mesoporous materials, aersol-based process, emulsion-based process, biocatalysis, sustained release, 3D hexagonal, 2D hexagonal, powder, spherical particles, liquid crystalline phases, AFM-porosimetry, Pluronic
National Category
Other Basic Medicine
Identifiers
urn:nbn:se:kth:diva-10089 (URN)978-91-7415-243-2 (ISBN)
Public defence
2009-04-03, E2, Lindstedsvägen 3, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20100811

Available from: 2009-03-19 Created: 2009-03-11 Last updated: 2014-11-03Bibliographically approved

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Microporous and Mesoporous Materials
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