NMR study of colloidal systems for pharmaceutical and microelectronics applications

Nuclear magnetic resonance (NMR) is unique to the study of heterogeneous multicomponent systems. NMR consists of a wide range of experiments that can be designed to monitor the interactions present in multicomponent systems on the molecular level. These experiments vary from classical 1D and 2D-NMR (such as 1H-NMR and chemical shift changes) to dynamic-NMR (such as relaxation time and diffusion measurements). In this thesis, some colloidal systems were selectively picked to demonstrate NMR's ability to study such systems.; The first system studied consisted of colloidal 1H-benzotriazole (BTA) aggregates in aqueous solutions (simplest). In this study, the self-assembly behavior of BTA in aqueous solutions below its solubility limit has been revealed for the first time using various NMR techniques, which include chemical shift, spin-lattice relaxation time (TI), and self-diffusion coefficient (D) measurements. The critical aggregation concentration (CAC) is estimated based on these NMR data to be about 16-20 mM. Such CAC value is comparable with the typical critical micelle concentration (CMC) for surfactants that have moderate aqueous solubility.; The second system examined was a more complicated one. It consisted of different liposome systems (conventional and polymer-stabilized) in the presence of a hydrotrope (sodium xylene sulfonate SXS). In this study two techniques were used to measure liposome size. NMR and dynamic light scattering (DLS) are both capable of measuring particle sizes depending on diffusion measurements. However, NMR data were more consistent since its capability to monitor the various components on the molecular level.; The third system consisted of colloidal multicomponent systems with silica and alumina model CMP solutions. These systems usually contain a complexing agent (e.g. glycine), anticorrosion agent (e.g. BTA), oxidizing agent (e.g. H2O2) and sometimes surfactants are added. The presence of H2O2 will lead to the presence of Cu+2 ions. Due to the complexity of these slurries, it is very hard to study the interactions taking place which will affect the CMP slurries performance. The first attempt to investigate such interactions using NMR is reported in this study. Longitudinal relaxation time (T1-NMR) was used to study the various interactions taking place in these dispersions such as adsorption, complexation or self-assembly.; It was demonstrated in this thesis the ability of NMR to study and investigate interactions in heterogeneous multicomponent systems. The systems under study were not disturbed nor there was a need to add any probing compounds. NMR proved to be an ideal choice to study a wide range of interactions (adsorption, self-assembly) using a variety of experiments. (Abstract shortened by UMI.)...