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Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices
Published on: March 27, 2019
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Pore shape and sorption behaviour in mesoporous ordered silica films.
Gerhard Fritz-Popovski1, Roland Morak1, Parvin Sharifi2
1Institute of Physics, Montanuniversität Leoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria.
Journal of Applied Crystallography
|October 15, 2016
Summary
Mesoporous silica films templated by pluronic P123 were prepared. Calcination causes pore shrinkage, resulting in elliptical pore shapes, which can be monitored by X-ray reflectivity changes with humidity.
Area of Science:
- Materials Science
- Nanotechnology
- Surface Science
Background:
- Mesoporous silica films are crucial for applications in catalysis, separation, and sensing.
- Controlling pore structure during film fabrication is essential for optimizing performance.
- Pluronic P123 is a common triblock copolymer used as a structure-directing agent.
Purpose of the Study:
- To investigate the structural evolution of mesoporous silica films during calcination.
- To characterize the resulting pore morphology and its impact on film properties.
- To explore methods for monitoring water uptake in these films.
Main Methods:
- Spin and dip coating techniques for film preparation.
- Calcination for template removal and structure formation.
- Grazing-incidence small-angle X-ray scattering (GISAXS) for structural analysis.
- X-ray reflectivity (XRR) and Yoneda-peak analysis for water uptake studies.
Main Results:
- Ordered cylindrical mesoporous silica films were successfully prepared.
- Calcination-induced shrinkage led to deformation of the cylindrical pores into elliptical shapes (axis ratio ~1:2).
- Shrinkage primarily occurred perpendicular to the substrate surface.
- Water uptake, influenced by relative humidity, was quantitatively monitored via shifts in the X-ray reflectivity critical angle.
Conclusions:
- The study elucidates the structural changes in mesoporous silica films during processing.
- The findings highlight the anisotropic nature of pore deformation.
- X-ray reflectivity provides a sensitive method for in-situ monitoring of pore hydration.
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