Applying Zeolitic imidazolate frameworks in thin film architectures

Constantinos Dimitrakakis
Zeolitic Imidazolate Frameworks (ZIFs) are of interest for highly specialised applications in fluid separation, chemical sensing and heterogeneous catalysis and the development of appropriate thin film structures that maximise the utilisation of these materials is of great importance. In this Dissertation, new techniques for the incorporation of ZIFs into various polymeric thin film architectures were explored to exploit their interesting structural and chemical properties. To this end, the
more » ... o this end, the chemical compatibility between ZIFs and polymers and the ability to exert control over the positioning of ZIFs on polymeric surfaces were explored in depth and new techniques developed to address these issues. A novel top down patterning process was successfully demonstrated and was the first top down technique described for ZIFs. A pre formed dense layer of ZIF 9 particles, over a layer of a photoresist material such as phenyltriethoxysilane or poly(o hydroxyl imide) on a silicon substrate, was exposed to intense X ray irradiation such that the photoresist underwent chemical hardening. The unexposed regions were then rinsed away to leave behind a patterned array of ZIF regions on the substrate, with no damage occurring to the ZIF material. A bottom up methodology was developed using radio frequency glow discharge plasma polymerisation to apply functional coatings over polytetrafluoroethylene substrates in a patterned manner using a physical masking process. It was found that plasma polymer coatings containing high quantities of oxygenated functionalities, such as carboxylic acid or hydroxyl groups, promoted the in situ growth of ZIFs on surfaces, while amine based plasma polymers instead inhibited growth. These coatings were also found to promote the growth of other porous framework materials. Subsequent functionalisation of the plasma polymer coatings in a second step was performed, using either 3 aminopropyltriethoxysilane or poly(styrene co maleic anhydride), to bind specifically to the plasma polymer treated regions of th [...]
doi:10.4225/03/58b77480e8bca fatcat:7fgycbmiqzaobjbwgso6myf3ae