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This thesis reports on the challenge of applying an innovative ‘soft-soft nanocomposite’ design strategy to establish synthesis parameters that affect the performance of coatings based upon water-borne latexes, which is driven by the environmental and legislative need to develop feasible alternatives to solvent-borne coatings. A framework emulsion polymerisation formulation to synthesise core-shell latexes with (poly[(butyl acrylate)-co-(butyl methacrylate)]) core and (poly[(butyl acrylate)-co-(butyl methacrylate)-co-(diacetone acrylamide)]) shell copolymer phases in a controlled manner was established, with high monomer conversions and approximately constant particle numbers. Retention of particle morphology in the films was confirmed using atomic force microscopy (AFM). The effect of adding adipic acid dihydrazide to the latex post-polymerisation to facilitate crosslinking of the shell phase during film formation was found to have a significant effect on the stress-strain properties of latex films. A core:shell mass ratio of 80:20 was found to be optimum in all crosslinked systems tested. Increasing the amount of crosslinking in the shell phase of the particles was found to have an effect on the large strain tensile properties of films, leading to strain hardening with reduced extension to break and higher failure stresses at higher crosslinker levels. Core phase copolymer Tg had a very significant effect upon the low strain mechanical properties, with Young’s modulus values of 5-180 MPa being accessible in the range of core Tg¬s from 5 – 25 oC, although little difference in mechanical behaviour was seen when varying the shell phase Tg from 5 – 15 oC. Adding 2 wt% methacrylic acid (MAA) to the shell phase copolymer gave an additional improvement in the low strain tensile region, with a Young’s modulus of 425 MPa being realised. However, it was found that additional amounts of MAA (up to 5 wt% in the shell phase) were deterious to film properties, with low Young’s modulus and poor extensibility. This was interpreted as being due to an increased concentration of ionomeric crosslinks restricting interparticle chain diffusion and keto-hydrazide crosslinking. Studies to evaluate the mechanical performance of soft-soft nanocomposite films compared to binder latexes used in commercial products were favourable, and showed that a high level of versatility with regards to mechanical properties is possible.

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Square planar metal bis-dithiolenes are interesting targets for incorporation into electronic and optoelectronic devices as they characteristically display multiple stable redox states, coupled with strong absorption at particularly low energies. This work focuses on novel methods for the formation of thin films of metal bis-dithiolenes for incorporation into devices. The synthesis, structure and spectroscopic properties of a novel class of polymerisable heteroleptic nickel dithiolene complex, containing pendent thiophene units, [Ni(R2pipdt)(b-3ted)] are described [R = Bz (3a), iPr (3b); pipdt = piperazine- 3,2-dithione; b-3ted = bis-(3-thienyl)-1,2-ethylenedithiolene]. Electrooxidation of (3a) showed it to incorporate into a polymeric film over an electrode surface, which consisted of intact dithiolene units, by covalent linking of the pendent thienyl groups. This polymer film showed some redox activity, with the intense, low energy, absorption red-shifted by 4360 cm-1. Co-polymerisation of (3a) with thiophene yielded a highly conductive film, with the intense, low energy, absorption red-shifted to a lesser extent (3500 cm-1). The films displayed interesting optical properties, however, their use was restricted by their poor redox activity, thought to be due to poor ion transport through the films. The synthesis of two novel dithiolene ligand systems, containing pendent polymerisable indolyl groups (mi-5edt and mi-5hdt), are described, and their incorporation into complexes investigated for nickel [Ni(mi-5edt)2 (6) and Ni(mi-5hdt)2 (8)], and copper f[Cu(mi-5edt)2][TMA] ([7][TMA]) and [Cu(mi-5hdt)2][TMA] ([9][TMA])g investigated [(mi-5edt) = 1-(N-methylindol-5-yl)-ethane-1,2-dithiolate and (mi-5hdt) = 1- (N-methylindol-5-yl)-hex-1-ene-1,2-dithiolate, TMA = tetramethylammonium]. Each complex was characterised in terms of its structure, redox and optical properties, and the effect of the ligand design, and the metal centre, compared. The complexes of nickel were shown to yield polymer films under electrooxidative conditions, through covalent linking of the indolyl groups, with superior redox activity to 3a, and with an equally intense low energy absorption. The monoanionic complexes of copper were shown to deposit, under electrooxidative conditions, as neutral molecular films that were otherwise unobtainable by conventional solution techniques. The incorporation of the more soluble novel indolyl functionalised nickel dithiolene 8 into electronic devices was investigated. Electrochromic devices were formed using poly- 8 as the active layer. The devices were able to switch their optical absorption profile at 860 nm through three absorbing states by application of a suitable potential difference across the film. Field-effect transistors were fabricated using a molecular film of 8 as the active layer. The devices showed ambipolar charge transport properties, though with a bias for n-channel operation, with mobilities μ ≈ 1 x 10-4 cm2V-1s-1. Photovoltaic devices were formed from a blended film of 8 with P-3HT and with MDMO-PPV [P-3HT = regioregular poly-3-hexylthiophene, MDMO-PPV = poly(2-methoxy-5- (3',7'-dimethyloctyloxy)-1,4-phenylene-vynylene)]. 8 was shown to contribute to the photocurrent at wavelengths beyond the polymer component, thus harvesting more visible light, however efficiencies below 0.1 % suggested inefficient charge transport by 8 in the film. Structurally continuous films of Ni(b-3ted)2 (10) could be formed by a process of electrodeposition. The formed films displayed conductivities 40 times greater than for conventional solution cast films. By a detailed study of the level of residual ion doping, the molecular packing, and the morphology of the films, this improved performance was attributed to the formation of a more dense polycrystalline array, with larger crystallites, which formed good electronic contact with the electrodes, and with each other. This electrodeposition technique was used to fabricate field-effect transistors from 10. The devices showed poor mobilities (μ ≈ 1 x 10 -8 cm2V-1s-1), owing to the poor intermolecular overlap of the dithiolene units in the solid-state, but suggested this technique to be suitable for a wide range of semiconductors, with more favourable electronic properties, as an alternative to conventional vapour or solution deposition.

<div>The advent of Patient-Centric therapy demands technologies capable of producing multiple versions of a given product, each tailored for specific segments of the population/individual, but in a time- and cost-effective manner. Prevailing manufacturing methods for oral dosage forms do not easily lend themselves for the transition to the Patient-Centric area. The purpose of this research was to develop a formulation/manufacturing platform technology meeting the flexibility requirements for Patient-Centric formulation and product development for oral dosage forms. The approach is based on the molecular designing and manufacturing of the dosage form. The dosage form consists of a 3D assembly of prefabricated functional modules, each with a specific pharmaceutical performance function. </div><div>The characterization of individual modules showed that solvent casting produced API-loaded HPMC films with homogeneous content distribution. The release profile of 3D assemblies was significantly influenced by the physicochemical properties of single modules. API-loading, thickness, and diameter had a significant effect on the release kinetics. In contrast, the hydrophobicity of the casting substrate did not affect the release kinetics. The initial geometry of the final 3D assembly given by the number of modules and their diameter was proved to have a significant impact on the release kinetics as well. </div><div>The 3D assemblies were used to produce dosage forms with customizable release profiles. Two API-loaded thin HPMC-based films with fast (FRA) and slow (SRB) release rates were produced by the solvent casting method. Accurate dose control (API loading) was accomplished by varying the number of individual modules in the 3D assemblies, whereas control of release kinetics was achieved by combining different ratios FRA and SRB film modules in the assembled dosage form. </div><div>The modular design was also tested for its ability to generate a dosage form of a weak-base API. This part was accomplished using a module containing citric acid (CA) interspaced between weak-base loaded FRA modules. Characterization of the 3D assemblies that were devoid of CA modules showed that the API release rate from modular assemblies containing weekly basic API exhibited strong pH-dependence. The 3D assemblies featuring CA modules in their design exhibited nearly pH-independent release kinetics. </div><div>Electrospinning was used as an enabling technology to produce HPMC-based fibrous films. HPMC films were able to encapsulate a wide variety of APIs with different aqueous solubility. All fibers produced were in the range of a few hundred nanometers to a few microns. X-ray diffraction and differential scanning calorimetry exhibited the amorphous or crystalline state of the API dispersed. Disintegration and release tests showed the fast dissolution of the fibrous system. </div><div><br></div>

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