Atom transfer radical polymerization (ATRP) is a controlled/living polymerization process used to synthesize polymers with controlled molecular weight and narrow polymer distributions. Control of these key parameters allows for the fabrication of well-defined macromolecular structures, a necessary tool for the synthesis of advanced materials. Since its discovery in 1995, ATRP has received considerable interest and widespread adoption from the academic community. Unfortunately, it faces several complex challenges which have hindered its full scale commercialization, mainly its high catalyst loadings to obtain fast reaction kinetics. One of the premises of this research project was to augment the slow reaction rates of ATRP while using extremely low catalyst concentrations. A hybrid ATRP system was employed which encompassed the fast reaction kinetics associated with conventional free radical processes, with the attractive control features of ATRP. When high free radical initiator concentrations in the range of 0.1 M to 0.2 M were used in concert with ATRP, fast reaction rates were realized, while maintaining a polymerization with living characteristics. Conversions of 81% (0.117M) and 91% (0.234M) were achieved within 2 hours as compared to typical ATRPs where achieving such conversions would take up to 24 hours. For those same free radical initiator loadings (0.117M and 0.234M) the reaction demonstrated living characteristics with molecular weight growing in a linear fashion with respect to increasing monomer conversion. Despite the high free radical initiator concentration, the polymer distribution remained relatively narrow, not exceeding a polydispersity of 1.30. Chain extension experiments from a synthesized macroinitiator were successful which demonstrated the living characteristics of the hybrid ATRP process. The aforementioned polymerizations were conducted with various copper concentrations. Catalyst concentrations as low as 16 ppm (0.234mM) were found to be effective, i.e. one catalyst mediated the growth of over 100 polymer chains, and thus saving post polymerization purification. Moreover, the expensive ligand cost could be cut dramatically through a nearly 100 time reduction in the ligand concentration for these polymerizations. A hybrid ATRP system was used as a unique method to determine termination rate coefficients of MMA at 70°C as a function of both conversion and chain length. A three dimensional composite map was developed to elucidate the coupling effects of both conversion and chain length on the termination rate coefficient over a total range of data which can be used for modelling systems of this nature. / Thesis / Master of Applied Science (MASc)

Light actinides and copper systems were studied using resonant soft X-ray spectroscopy. An instrumental and experimental setup for soft X-ray spectroscopy meeting the requirements of a closed source for radioactivity was developed and described in detail. The setup was used for studies of single-crystal PuO2 oxidation. The existence of higher oxidation state than Pu(IV) in some surface areas of the single crystal were found from O 1s X-ray absorption measurements. Furthermore, from comparison with first principles calculations it was indicated that plutonium oxide with Pu fraction in a higher oxidation state than Pu(IV) consists of inequivalent sites with Pu(IV)O2 and Pu(V)O2 rather than a system where the Pu oxidation state is constantly fluctuating between Pu(IV) an Pu(V). It was shown that a combination of resonant O Kα X-ray emission and O 1s X-ray absorption spectroscopies can be used to study electron correlation effects in light-actinide dioxides. The electronic structure of copper systems was studied using resonant inelastic soft X-ray scattering and absorption spectroscopy. It was found that X-ray absorption can be used to monitor changes in the oxidation state but as differences between systems with the same oxidation state are in many cases small, speciation is uncertain. Therefore, a method utilizing resonant inelastic X-ray scattering as fingerprint to characterize complex copper systems was developed. The data recorded at certain excitation energies revealed unambiguous spectral fingerprints for different divalent copper systems. These specific spectral fingerprints were then used to study copper films exposed to different solutions. In particular, it was shown that resonant inelastic X-ray scattering can be used in situ to distinguish between CuO and Cu(OH)2, which is difficult with other techniques.

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