Since their discovery in the late 1970s conducting polymers have become increasingly used materials in many applications. They are utilised for their conductivity and/or their electroactive properties. These applications include sensor technologies, actuators, and battery materials. The properties of conducting polymers rely on the extent of the reduction / oxidation or redox state, and hence the dopant levels, of the materials. The aim of this work was to investigate the use of the Ion Beam Analysis (IBA) techniques Rutherford Backscattering Spectroscopy (RBS), and Proton Induced X-ray Emission (PIXE) for the analysis of 'soft' organic materials, in particular, conducting polymers. These IBA techniques are not new, as they have been extensively used for the characterisation of many inorganic, 'hard', materials such as aluminium oxide and silicon oxynitride. While they have been used to alter the molecular structure, and hence the properties of conducting polymers in the past, little to no research has explored the use of ion beams as a tool for the characterisation of these materials. Conducting polymers can either be prepared chemically or electrochemically. They are predominantly prepared in an oxidised state and this charge is balanced by negatively charged counter ions. In this work, the conducting polymers were formed electrochemically by deposition onto support materials at constant electrode potential. The number of counter ions required to balance the polymer chain depends on the type of conducting polymer formed and extent of oxidation. Issues such as the influence of the support material and extent of polymer oxidation on the extent of counter ions through the polymer films are of importance. Gaining knowledge of the dispersion of counter ions may provide new insights into the redox mechanisms for conductive polymers. Complex bis terthiophene porphyrin conducting polymers were prepared and investigated for the uptake of zinc into the freebase porphyrin unit after polymerisation by acquiring elemental depth profiles using RBS analysis. Issues such as the influence of the support material and extent of polymer oxidation on the extent of counter ions through the polymer films were found to be of importance. Gaining knowledge of the extent of counter ions provides new insights into the redox mechanisms for conductive polymers. The results were compared to those obtained for a sample where zinc was coordinated to the porphyrin prior to the polymerisation process. Unexpected high concentrations of both nitrogen and oxygen were found, which were interpreted to be due to entrapped cations originating from the electrolyte ((Bu)4N+), together with trapped water molecules, within the polymer films. The chlorine depth profiling assisted with understanding the extent of the perchlorate counter ion throughout the polymer films. The combination of both RBS and PIXE demonstrated that trace element impurities can be detected using ion beam analysis, which other analytical techniques are unable to do. A series of polypyrrole films incorporating a range of counter ions were prepared as model compounds for study in the second section of this work. RBS and PIXE techniques were used to evaluate film homogeneity with respect to depth and to infer the counter ion / pyrrole unit ratio for each of the six PPy film formed. RBS was also used to characterise a series of terthiophene-ferrocene based conducting co-polymers. The ratio of co-polymer monomer to terthiophene-ferrocene monomers and the dopant levels for the polymers were determined using a RBS deconvolution method developed in this study. This new method can be extended for characterization of a wide range of organic polymers. The limitations of RBS for the analysis of these soft materials were identified. The advantage that RBS offers over other analytical techniques is that it provides a means for low atomic number element depth profiling in these materials.

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L’objectif de cette thèse est d’étudier les interactions entre polyélectrolytes (PE) de charges opposées par analyse frontale continue en électrophorèse capillaire (FACCE) et par titration calorimétrique isotherme (ITC), en fonction de la force ionique du milieu et des paramètres physico-chimiques relatifs aux deux partenaires (taux de charge chimique, masse molaire, ramification). Un copolymère statistique d’acrylamide et de 2-acrylamido-2-méthyl-propane sulfonate (PAMAMPS) de taux de charge variant entre 15% et 100% a été synthétisé et caractérisé pour cette étude. En tant que polycation modèle, la poly(L-lysine) a été retenue, sous sa forme linéaire (PLL) ou ramifiée / hyperbranchée (DGL). Des mesures par turbidimétrie ont permis d’étudier la stabilité des complexes de polyélectrolytes (PEC) en fonction de la force ionique du milieu. La détermination de la stœchiométrie des PEC par 1H-RMN a permis d’établir une règle générale pour prédire les stœchiométries de charge des PEC. Les paramètres thermodynamiques d’interactions (constantes et stœchiométries d’interaction, contribution entropique et enthalpique) ont été déterminés, par le tracé systématique des isothermes d’adsorption, en considérant le modèle d’interactions des sites indépendants de même énergie. Une dépendance linéaire entre le logarithme des constantes d’interactions et le logarithme de la force ionique a été observée. Cette dépendance en force ionique confirme le caractère entropique des interactions entre PE de charges opposées. Elle permet aussi de quantifier le nombre de contre-ions relargués lors de la formation du PEC. Cette quantité de contre-ions libérés a pu être comparée à la quantité totale de contre-ions condensés. Cette modélisation permet, en outre, de prédire les constantes d’interaction pour des taux de charge intermédiaires et à différentes forces ioniques. / The aim of this thesis is to study the interactions between oppositely charged polyelectrolytes (PE) by frontal analysis continuous capillary electrophoresis (FACCE) and isothermal titration calorimetry (ITC) as a function of the ionic strength of the medium and the physico-chemical properties related to the two partners (chemical charge density, molar mass, ramification). Statistical copolymers of acrylamide and 2-acrylamido-2-methyl-propane sulfonate (PAMAMPS) with chemical charge densities varying between 15% and 100% were synthesized and characterized for this study. Poly(L-lysine) under their linear (PLL) or ramified/hyperbranched (DGL) forms were used as model polycations. Turbidity measurements allowed the study of the stability of the polyelectrolyte complexes (PEC) as a function of the ionic strength of the medium. PEC charge stoichiometries were measured by 1H-NMR, and a general predictive rule that estimates the PEC charge stoichiometry was enounced. The thermodynamic binding parameters (binding constant, stoichiometry, enthalpic and entropic contributions) were determined, by systematically plotting the isotherms of adsorption, and using the model of independent and identical interacting sites. A linear dependence between the logarithm of the binding constants and the logarithm of the ionic strength was observed. This linear dependence confirmed the entropic character of the interactions between oppositely charged PE and allowed quantifying the number of released counter-ions that were compared to the total number of condensed counter-ions. Furthermore, this modelling allowed predicting the binding constants for intermediate chemical charge densities and at different ionic strengths.