High throughput optical materials

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.<br/>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.<br/>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 been examined.<br/>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.<br/>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.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2008

Author dc:creator

• Hogben, Mark James

Advisor dc:contributor.advisor

• Weller, Mark