Hogben, Mark James
High throughput optical materials.
University of Southampton, School of Chemistry,
The synthesis and characterisation of a variety of zeolites and aluminosilicates
has been achieved using hydrothermal methods and solid state calcinations. The
system using elemental aluminium, silica and sodium hydroxide solution as starting
materials was explored using hydrothermal methods (200°C), and reactions conditions
were optimised for the formation of analcime, sodalite, zeolite A and faujasite. All
materials were characterised using powder x-ray diffraction.
The thermal conversion of zeolite A and sodium chloride into sodalite has
been studied using combined TGA and DTA analysis and time resolved powder
neutron diffraction heating up to 800°C. It was found that the thermal conversion
occurred at 550°C and no intermediate phases were observed during this transition.
The synthesis and characterisation of a range of reversibly photochromic
sodalites has been achieved via thermal processing of zeolite A with sodium sulphate
and a variety of group I metal salts. All of the sodalites adopt the space group P-43n
and were characterised by powder neutron diffraction and Rietveld refinement.
Structural refinements show that substitutions at non-framework sites alter the
framework bond distances of the sodalite and the observed optical property. Different
colours of reversible photochromism have been observed and tailored by use of
different salts in the synthesis, and trends between structure and optical property have
Synthesis of the anhydrous zeolite type phase K2Al2Si3O10(KCl) with
edingtonite topology has been achieved using a high temperature, high pressure
reaction (600°C, 7000psi). Rietveld refinement of powder x-ray diffraction in the
space group P-421m was performed. The tetragonal unit cell was found to have
refined lattice parameters of a = 9.7488 and c = 6.4879. Structural considerations have
been examined as to the inaccessibility of the analogous rubidium phase.
Several different methods for formation of zeolite films have been
investigated, and the properties of these films compared with view to thermal
processing of the films, or forming the basis of a high throughput solid state array.
Films were characterised using powder x-ray diffraction and scanning electron
microscopy. Thermal processing of the zeolite films was performed to collapse the
zeolite into a reversibly photochromic sodalite.
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