Azobenzene based photochromics have been studied widely since the development of the
first azo dye, Mauvine, by Perkin in 1856. Azo based dyes have been widely used in industry
for over a century. The desire to study them arose from their ease of synthesis and the wide
availability of colours which can be tuned by manipulation of the chromophores on the azo
The ability of azobenzene to photoisomerise between trans and cis states is widely known.
The change in dipole moment affords the ability to fine-tune surfaces via photoisomerisation
of the azo molecule. The objective of this investigation was to alter the surface properties of
a variety of substrates via the photoisomerisation reaction of several perfluoroalkyl derived
azobenzene compounds. These compounds are novel and are based on the idea of the
fluoroalkyl chain creating a superhydrophobic surface, similar to Teflon, which would
change surface energy upon isomerisation of the azobenzene molecule to give a more
hydrophilic surface. This would ultimately then be utilised to coat a fabric surface to provide
a photosensitive coating.
The compounds used in this work (Admat 1 and 2 and Cfam derivatives) were synthesised in
order for their photochemistry in solution and on surfaces to be investigated. The studies
began with the photoisomerisation investigations in solution and the calculation of the rate
constant and finally the activation energies of these compounds in a variety of common
solvents. Interesting results were observed in polar protic solvents which were investigated
further. The discovery that aggregation occurred in polar protic solvents due to solubility
issues, which in turn led to a fast rate constant was a key finding of the solution work.
The surface studies began with the investigation of cellulose as a substrate due to the
structural similarity it has with cotton. The azo compounds were derivatised using cyanuric
chloride to afford a triazinyl group which was able to attach to the surface of the cellulose via
the hydroxyl groups on the surface.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.