<p>In this thesis work, two new CO₂-responsive monomers have been synthesized. These amidine-containing monomers were prepared in a simple and effective one-step reaction, giving a very high yield (98.5 %) of product. Furthermore, there was no complicated further purification required to obtain the highly pure product. The CO₂ switchability, conductivity and partitioning of the monomers were measured. It was confirmed that the monomers could be protonated CO₂ in the present of trace amount of water and reversibly switched back and forth to their natural forms by N₂ at room temperature.</p> <p>The polymers having different molecular weights were prepared from one monomer via conventional free radical polymerization method. The polymers also showed the reversible switchability property with CO₂ and N₂ stimuli. This was confirmed by the results of conductivity and partitioning tests. Temperature showed a major influence on the conductivity of the monomer and polymers. The effect of molecular weight on the polymer switchability of was further investigated through conductivity tests and potentiometric titration. The conductivity decreased with the increased molecular weight. The apparent equilibrium constant (pK_a)decreased with the degree of protonation (δ) suggesting that the basicity of the polymers is strongly depended on the value of δ.</p> / Master of Applied Science (MASc)

Yes / A novel fluorescent monomer was synthesized to probe the state of CO2-responsive cross-linked polymeric particles. The fluorescent emission of this aminobromomaleimide-bearing monomer, being sensitive to protic environments, can provide information on the core hydrophilicity of the particles and therefore indicates the swollen state and size of the particles. The particles’ core, synthesized from DEAEMA (N,N-diethylaminoethyl methacrylate), is responsive to CO2 through protonation of the tertiary amines of DEAEMA. The response is reversible and the fluorescence emission can be recovered by simply bubbling nitrogen into the particle solution. Alternate purges of CO2 and N2 into the particles’ solution allow several ON/OFF fluorescence emission cycles and simultaneous particle swelling/shrinking cycles. / British Petroleum Company (BP), Engineering and Physical Sciences Research Council (EPSRC)