The interaction of water droplets with hydrophobic or rough, superhydrophobic solid surfaces has been studied. Such surfaces may be found in the natural world and their potential applications range from waterproof and self-cleaning surfaces to droplet microfluidics. A measure of hydrophobicity is obtained from the angle between the liquid and solid surface measured from the solid through the liquid, known as the contact angle. Variations in this angle can indicate not only a level of ‘wetting’ of the surface but also small amounts of droplet movement and may be achieved by electrowetting, the application of a voltage between a liquid droplet and a substrate, and/or by varying the local topography of the surface. Photolithography and thin-film deposition fabrication techniques have been used to create hydrophobic and superhydrophobic surfaces for use in electrowetting experiments. Both AC and DC electrowetting behaviour has been investigated and the results have been shown to be in agreement with past work and well established theory. Liquid marbles have been investigated as water drops displaying extreme non-wetting behaviour, with conformal coatings forming textures similar to those formed by the topography of a super-hydrophobic surface. It has been demonstrated that for such marbles both AC and DC reversible electrowetting may be achieved and shape oscillations may be observed having nodal patterns of these oscillations which are due to stationary capillary surface waves which are accurately described by theory. Electrostatic actuation of controllable, bi-directional motion of liquid marbles has also been demonstrated on a patterned electrode structure with and without an insulating layer. Electrodeposited rough copper surfaces were created with a surface topography gradient to control the directional movement of water drops and collect them with a view to applications in large scale water harvesting. The effects of surface roughness on the sensor response to liquid loading of a Quartz Crystal Microbalance (QCM) has also been investigated using three different surface coating materials. Liquid penetration between surface features differed between the materials and those upon which the liquid penetrated exhibited a characteristic low slip length or trapped mass type effect whereas those upon which it did not exhibited a slip length introduced by the air layer between the liquid and the crystal.

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he ferroelectric phase transition in KD2PO4has been studied using coherent neutron inelastic scattering. The low frequency phonon dispersion relations were determined in the two principal symmetry directions. The results were fitted to a central force rigid ion model which gave good agreement with the acoustic branches and fee lowest frequency optic branches. Group theory was used to simplify all calculations. None of the phonon modes was temperature dependent and therefore the ferroelectric transition was not caused by a soft mode. Quasi-elastic critical scattering was observed, the intensity of which increased as fee transition temperature was approached. The scattering extended throughout each lirillouin zone and was peaked at reciprocal lattice points. The variation of fee intensity in the scattering plane showed that fee displacements of the atoms in the ferroelectric fluctuations were similar to those relating fee paraelectric and ferroelectric phases. The distribution of the intensity around each reciprocal lattice point showed the effect of the macroscopic field associated wife the ferroelectric fluctuations. A simple Ising model wife next nearest neighbour and Coulomb interactions described fee results well. A microscopic model for KDP type crystals is proposed. The model neglects sail dynamic effects, describes the experimental results and shows that the interaction of the phonons with the ferroelectric fluctuations is of more importance than previously thought. The model also predicts the shape of ferroelectric critical scattering to other ferroelectric and antiferroelectric KDP type crystals.

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The development of selective heterogeneous catalytic systems is of fundamental importance for the realisation of sustainable green chemical processes. In this thesis, the hydrogenation of nitroarene, aldehyde and carboxylic acid compounds is examined in continuous gas phase operation, for the synthesis of a target functionalised aromatic amine and alcohol. Novel catalysts based on Mo nitride, carbide and supported Au have been synthesised and subjected to an array of complementary characterisation measurements that provide catalyst structure/performance correlations with detailed kinetic and mechanistic analysis. The use of Mo2N and Mo2C as catalysts served to promote the selective hydrogenation of nitrobenzene to aniline and p-chloronitrobenzene to p-chloroaniline where the incorporation of nano-scale Au increased reaction rate. Activity has been correlated to hydrogen adsorption/release capacity, which shows a dependence on the degree of nitridation and crystallographic structure. In contrast, hydrogenation of benzaldehyde is limited by C=O activation, which is facilitated by the Mo component. Alumina supported Au has exhibited 100% selectivity in the hydrogenation of benzaldehyde and 4-nitrobenzaldehyde to the target alcohol, where Au particle size and surface Lewis acidity play crucial roles. The hydrogenation of benzoic acid over Au supported on a CeO2-ZrO2 mixed oxide has shown promising results with the possibility of a one step transformation to the alcohol. The results presented in this thesis establish feasible catalytic routes to high value amines and alcohols where critical process optimisation is demonstrated in terms of catalyst composition/surface structure and reaction conditions.

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