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<p>This work detailed in this thesis has developed two new technologies for modifying polymer surfaces with variable chemistry and topography: 1. Surfadditive (surface-active-additive) approach for polymer surface chemistry modification during molding. This concept was demonstrated by the synthesis and application of two types of surfadditives. The first type of surfadditive is a block copolymer having the “head-neck-body” structure. The “head” and “neck” of the chain molecule provides functionality and enables the surfadditive to migrate to the surface, while the “body” of the molecule provides rooting to the bulk material. The second type of surfadditive is a magnetic nanoparticle having an iron core and PMMA/POSS block copolymer shell. Both surfadditives were successfully applied in the molding processes of PMMA samples for surface chemistry modification. Various factors affecting the migration processes were investigated; 2. A one step “cutting-edge” based on controlled chattering for surface topography construction (patterning). This technology was developed by using an oscillating diamond knife in ultramicrotomy and was operated at high cutting speed with controlled oscillation. One dimensional wavy patterns on PMMA and epoxy sample surfaces were successfully fabricated by this one-step method. The sizes of patterns were tunable form 30 nm to 3 µm through adjusting cutting speed and oscillation frequency. Besides, this technology was also able to fabricate nanowires structures with high aspect ratios (10,000) and adjustable sizes from a variety of materials.</p> / Doctor of Philosophy (PhD)

In this thesis, acrylic polymers (methyl methacrylate, MMA; N,N' -dimethylamino ethyl methacrylate, DMAEMA; oligo-ethylene glycol methacrylate, OEGMA; trifluoroethyl methacrylate, TFEMA) were grafted from various metal surfaces such as cold rolled steel (CRS), stainless steel (SS), aluminum (Al) and nickel (Ni) through surface-initiated atom transfer radical polymerization (s-ATRP). The purpose is to improve corrosion resistance and to introduce multi-functionality to metal surface. The metal substrates were precisely polished and were facile for characterization by ellipsometry. 3-((alpha)-Bromo-2-methyl) propylamide propyltriethoxysilane was synthesized and immobilized on the metal surfaces under a simple and workplace-friendly condition. Grafting density was estimated to be 0.58 chains/nm^2 for CRS-gPMMA, 0.55 chains/nm^2 for Ni-g-PMMA and 0.18 chains/nm^2 for SS-g-DMAEMA and 0.66 chains/nm^2 for SS-g-PDMAEMA. Two strategies, i.e., "adding free initiator" and "adding deactivator", were adopted for the control over polymer molecular weight and grafting density in the CRS-g-PMMA system. The polymer thicknesses up to 80 nm were obtained within 80 min using the "adding deactivator" strategy. Copper and iron catalyst systems were compared on different metal substrates. A severe deactivation of copper catalyst was observed on the metal substrates. Controlled polymerization with relatively low polydispersity was obtained using the iron catalyst. The metal surfaces at various stages of modification were characterized by X-ray photoelectron spectroscopy, ellipsometry, goniometry, and atomic force microscopy (AFM). Electrochemical experiments were also carried out to measure the polarization resistance and corrosion potential of CRS-g-PMMA substrates. This thesis work demonstrated that the surface-initiated ATRP is a versatile means for the surface modification of metals with well-defined and functionalized polymer brushes. / Thesis / Master of Applied Science (MASc)

Surface functionalised silica materials have been prepared, followed by the extensive testing of their ability to remove metal ions from aqueous solutions. Modifications include ligand attachment and polymer grafting from the silica surface whilst the metals tested range from first row transition metals right through to the lanthanides and actinides. Characterisation of the materials produced has been of paramount importance for the understanding of the modification process and this is also extensively discussed. Atom transfer radical polymerisation (ATRP) has been used as the primary polymerisation method. Following polymerisation of 2-hydroxyethyl methacrylate (HEMA), post functionalisation was attempted. However, this was found to cause severe cross-linking and all attempts to attach ligands to this failed. Nonetheless, this process was transferred to grafting from silica surfaces and a novel approach to the characterisation of this material was implemented. (3-aminopropyl) triethoxysilane (APTES) was reacted with multiple forms of silica, primarily ZEOprep silica (average particle size 71.48 πm) and fumed silica (0.007 μm). This produced an amine coated surface to which 2-bromoisobutyryl bromide (BIBB) was attached, providing the required surface for radical polymerisation to proceed with a selected monomer. Solid State Nuclear Magnetic Resonance (SSNMR) has been utilised as the major characterisation technique for each step, leading to significant understanding of how this occurs. Thermogravimetric Analysis (TGA) and elemental analysis has supported this method at each stage whilst also enabling one to calculate the moles of APTES present, per gram of APTES-functionalised silica. For the ZEOprep silica this was calculated to be at up to 1.51 x 10-3 mol g-1 and for the fumed silica 1.63 x 10-3 mol g-1. As well as testing the selective nature of these materials, solutions of individual ions and radionuclides were used to measure the effectiveness of the materials for a specific ion. Rd values for these metals ions including solutions of Co(II), Ni(II), Cu(II), Cd2+, Eu(III) and [UO2]2+ have reached values ranging from 7.49 x 104 mL g-1 to as high as 2.17 x 109 mL g-1. These values are regarded as outstanding by other groups that have reported similar results and these are discussed in the report. This range includes values that were observed when competing Na+ and Ca2+ ions were present at 0.5 % and 1 % (w/w). pH testing was also investigated with the materials using a solution of europium ions to determine the most effective range and this was found to fall between pH 4 and 5. X-ray Photoelectron Spectroscopy (XPS) has been utilised to help gain an understanding of the binding between Cu(II) ions and APTES, suggesting that copper ions bind with oxygen atoms closer to the silica surface as well as the nitrogen atoms at the end of the ligand. Meanwhile STEM (Scanning Transmission Electron Microscope) has been used to show how effectively the surface area of the material is used by imaging the europium ions over a sample of APTES-functionalised fumed silica. Ligands and polymers have been focussed on to build a catalogue of functional materials and this has been achieved in collaboration with PhosphonicS Ltd. The most significant finding from these selective investigations was that uranyl ions were found to be the most readily removed. Cu(II) and Eu(III) ions were also removed relatively effectively whilst Co(II), Ni(II), Zn2+ and Cd2+ proved the most challenging but certainly not impossible. [UO2]2+ concentrations were reduced from 17.1 ppm to 1.6 ppm after 4 weeks with use of the ligand SEA (2-aminoethyl sulfide ethyl silica), even with six other metal ions present at similar initial concentrations and a starting pH of 4.67 by adding just 50 mg of the material to a 45 mL solution.

Le confinement de polymères incompatibles au sein de particules induit une séparation de phase et conduit à la formation de morphologies particulières (cœur-écorce, hémisphérique…). Cette nanostructuration est à l’origine de propriétés de filmification particulières qui justifient l’utilisation des particules polymères composites dans le cadre d’applications comme la formulation de peintures ou de revêtements. Ce travail s’intéresse au développement d’approches permettant de préparer ces particules polymères composites en une seule étape et en milieu aqueux. La stratégie proposée repose sur le couplage « en simultané » de deux polymérisations distinctes: la polymérisation de cyclooléfines par métathèse (ROMP) et la polymérisation radicalaire par transfert d’atome (ATRP). Après avoir mis en évidence les difficultés liées au couplage de la ROMP et de l’ATRP en milieu dispersé aqueux, deux approches originales faisant intervenir respectivement des conditions de miniémulsion et de microémulsion sont proposées. Pour chacune d’elles, la présentation du principe de la synthèse et l’analyse de ses résultats précèdent l’étude morphologique des particules produites. / So as to broaden the scope of their applications in paints, coatings and impact-resistant plastics, many investigations have been dedicated to the preparation of nanostructured colloids over the past decades. Original morphologies including core-shell, hemispherical and complex occluded structures (raspberry-like, golf ball-like, octopus-like) can now be readily prepared. This work proposes a new straightforward one-pot, one-step, one-catalyst strategy to prepare polymer composite particles based on the simultaneous combination of two mechanistically distinct polymerizations in aqueous dispersed media. Norbornene (NB) and methyl methacrylate (MMA) were converted via Ring-Opening Metathesis Polymerization (ROMP) and Atom-Transfer Radical Polymerization (ATRP), respectively. Two original routes, designed to ensure simultaneous ROMP and ATRP, respectively under mini- and microemulsion conditions, are proposed. Both are successively reviewed on chemical and colloidal levels. Specific attention is paid to the morphologies of the prepared particles.