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Functional water-soluble polymers find applications in a variety of fields including waste-water treatment, pharmaceuticals, cosmetics, drug delivery, and hygiene. Despite the increased demand for these products, understanding of their synthesis by free-radical aqueous-phase polymerization has lagged behind that of polymers produced in organic solvents. In this doctoral work, the free-radical batch and semibatch aqueous-phase polymerization of N-vinylpyrrolidone (NVP), N-vinylformamide (NVF), N-vinylimidazole (NVI) and quaternized vinylimidazole (QVI), as well as NVP polymerized in n-butanol, has been studied. Kinetic models are developed to describe monomer conversion and polymer molecular weight (MW) behaviour of these systems. The expressions developed from independent pulsed-laser studies for propagation (kp) and termination (kt) rate coefficients, including their variation with monomer concentration and conversion, are shown to provide an excellent description of aqueous-phase NVP polymerization. Polymerization of NVP in butanol and of NVF in water are well-represented by the base NVP model, with differences in polymerization rate and polymer MWs simply accounted for by the differences in kp for the systems, indicating that the kt behaviour must be quite similar. The NVI/QVI study demonstrates the importance of a pH-dependent degradative addition reaction to monomer for NVI, with polymerization behaviour identical to that of QVI for pH 1, an effect captured in the model developed to describe the system. The aqueous-phase copolymerization of NVP and NVF was also studied, and reactivity ratios were determined to be very close to unity. This information was combined with the kp and kt expressions used to describe NVP and NVF homopolymerizations, with no other additional parameters required to model the copolymerization rate, copolymer composition and copolymer MW. This result demonstrates that the improved homopolymerization knowledge of these water-soluble monomers can be easily extended to understand their behaviour in copolymerization. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2011-12-21 16:05:14.904

Il a été démontré que l’acidité de l’environnement tumoral jouait un rôle dans la résistance aux chimiothérapies. L’utilisation de nanovecteurs, tels que les nanocapsules lipidiques (LNC), permet non seulement d’améliorer le temps de biodistribution de substances actives, mais aussi de cibler l’environnement tumoral tout en protégeant les actifs de cet environnement acide. L’objectif de cette thèse porte ainsi sur l’optimisation et l’évaluation de LNC furtives et pH-sensibles dans le contexte du mélanome.Dans un premier temps, ces travaux ont consisté à caractériser la vascularisation de mélanomes humain et murin. Ces études ont permis de comparer différentes tumeurs (densité, taille et structure) et de déterminer si l’usage de nanomédecines est approprié dans ce contexte.La seconde partie s’est orientée sur l’élaboration de polymères combinant furtivité et pH-sensibilité. Ces copolymères composés de N-vinylpyrrolidone (NVP)et de vinylimidazole ont été synthétisés par polymérisation RAFT et post-insérés à la surface des LNC. Ces modifications ont donné lieu à des LNC présentant des charges de surface pH-dépendantes,entrainant une augmentation de leur internalisation à pH acide dans des cellules de mélanome. Finalement, des études de biodistribution ont mis en évidence l’intérêt de la NVP dans le développement de nanovecteurs furtifs. En conclusion, les copolymères développés ont permis de prolonger le temps de circulation, mais aussi d’apporter des propriétés pH-sensibles qui pourraient améliorer l’internalisation tumorale des LNC in vivo et donc de potentialiser l’effet d’une thérapie anticancéreuse. / Tumor acidity has been shown to play a major role in resistance to chemotherapy. The use of nanomedicines, as lipid nanocapsules (LNC), allows to protect drugs from this acidic environment. They can also improve the biodistribution of therapeutics and to target the tumor environment. The aim of this thesis concerns the evaluation and characterization of stealth and pH-sensitive LNC in the context of melanoma. Firstly, these works consisted in characterizing the vascularization of human and mice melanoma. These studies allowed to compare different tumors (density, size and structure), and determine if the used of nanocarrier is suitable in the context of melanoma.The second part of this thesis described the development and the characterization of new copolymers, combining stealth and pH-sensitive properties. These copolymers, composed of Nvinylpyrrolidone(NVP) and vinylimidazole, were synthesized by RAFT polymerization and were post in sertedonto LNC surface. These modifications allowed to obtain charge reversal nanocarriers, leading to increase their melanoma cell uptake underacid pH. Finally, biodistribution of these modified nanoparticles was studied in vivo and highlighted the interest of NVP in the development of stealth nanocarriers. To conclude, the developed copolymers able to extend nanocarrier circulation time and to provide pH-responsive properties which should increase the tumor internalization of LNC invivo and potentiate the effect of anticancer drugs.

ABSTRACT BIOSENSOR BASED ON INTERPENETRATED POLYMER NETWORK OF ALGINIC ACID AND POLY (1-VINYLIMIDAZOLE) Kartal, M&uuml / jgan M.S., Department of Chemistry Supervisor : Prof. Dr. Levent Toppare January 2008, 63 pages A new proton conductor polymer was prepared using alginic acid (AA) and poly (1-vinylimidazole) (PVI). The polymer network was obtained by mixing AA and PVI at various stoichiometric ratios, x (molar ratio of the monomer repeat units). The AA/PVI network was characterized by elemental analysis (EA) and FT-IR spectroscopy. Potential use of this network in enzyme immobilization was studied. Enzyme entrapped polymer networks (EEPN) were produced by immobilizing invertase and tyrosinase (PPO) in the AA/PVI network. Additionally, the maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were investigated for the immobilized invertase and enzymes. Also, temperature and pH optimization, operational stability and shelf life of the polymer network were examined.