| The organic-inorganic hybrid nanoparticles and nanocapsules were elaborated via miniemulsion copolymenzation of styrene (St) andγ-methacryloxypropyltrimethoxysilane (MPS) in which the free radical copolymenzation of vinyl groups is accompanied with the hydrolysis and condensation of MPS. The hybrid materials embody the excellent properties of polymers and inorganic materials, and therefore the applications of this kind of materials are extended in more and more fields, such as coating, catalyst, biology, medicine and cosmetics. In this thesis, the kinetics, the reaction mechanism, the colloidal properties of latex particles, and the microstructure of hybrid copolymers in the miniemulsion copolymerization of MPS and St were investigated, as well as the formation mechanism and determining factors for the synthesis of polymeric or organic-inorganic hybrid nanocapsules via interfacial copolymerization in miniemulsion by using an oily template.Kinetic experiments were carried out to analyze the effects of the MPS weight content, the nature and amount of initiator, and the surfactant concentration on the copolymerization rate. At low conversions, an increase in the MPS concentration led to an increase in the copolymerization rate due to the higher MPS propagation rate coefficient and its higher water solubility, compared to St. The copolymerization rate and the St polymerization rates decreased at higher conversions presumably due to the formation of a silane-rich interface near the particle surface which decreased the rate at which oligomers could undergo entry. The kinetics of the miniemulsion polymerization reaction performed in the presence of 2, 2'-azobis(isobutyronitrile) (AIBN) supports this hypothesis. As the radicals were mainly produced in the oil phase, the overall kinetic process was no longer influenced by the presence of the silane monomer. In the case of potassium persulfate (KPS), the copolymerization rate was found to be nearly independent of the amount of initiator while it was strongly influenced by the surfactant concentration.Increasing the surfactant concentration led to an increase in the rate of hydrolysis indicating that hydrolysis was taking place at the particles/water interface. The rate of hydrolysis was moderate under neutral conditions but increased rapidly at high and low pH. The siloxane oligomers formed under basic or neutral conditions had an influence on the kinetics process which is presumably related to differences in oligomers architecture. Premature crosslinking could be avoided under neutral conditions and minimized in basic conditions even for a high initial MPS weight content.The properties of latex particles were investigated in terms of the suspension pH, the MPS weight content, the nature of initiator, and the sodium dodecyl sulfate (SDS) concentration. In contrast to neutral conditions, the initial miniemulsion with a smaller droplet size was obtained under basic and acidic conditions. As the polymerization proceeded, the particle size showed a much rapider increase under acidic and basic conditions than that of neutral conditions. Under neutral conditions, the latex particles in the system initiated by AIBN showed a better colloidal stability than that of the system initiated by KPS. The results of FTIR and DSC indicated that the incorporation of MPS in the polymer chains was mainly via free radical copolymerization.According to the thermodynamic analysis, the morphology of nanocapsules is not the favorite for the ternary system of polystyrene/octane/aqueous solution of SDS. However, polymeric nanocapsules with crosslinked shells could be elaborated by interfacial miniemulsion copolymerization of styrene, N-isopropylacrylamide (NIPAM), and divinylbenzene (DVB) through encapsulation of a hydrocarbon in one step. In this process, NIPAM and DVB played key roles in inducing the interfaces of the nanodroplets to be the loci of polymerization. FTIR and solid-state 13CNMR spectroscopic analyses have confirmed that NIPAM molecules were incorporated into the shell copolymers. An investigation of the influence of the amount of DVB on the formation of nanocapsules in the presence of NIPAM has further confirmed that the nanocapsules are formed by an interfacial miniemulsion polymerization mechanism. An increase in the monomer content of the oil phase is detrimental to the formation of nanocapsules.Although the morphology of nanocapsules was not the most favorable state for the ternary system of poly(MPS-co-PS)/Hexadecane (HD)/aqueous solution of SDS, the organic-inorganic hybrid nanocapsules were elaborated by interfacial copolymerization of St, MPS, NIPAM and DVB (optional) in miniemulsion under different pH conditions. It has been shown that the droplet size and droplet size distribution of the miniemulsion were extremely influenced by the water solubility of the oil phase, the monomer content, surfactant concentration and NIPAM amount. Smaller droplets with a relatively narrow size distribution could be prepared by introducing a higher amount of monomer, by using HD as template or by increasing the surfactant concentration.According to DLS analysis, most of the large droplets originally present in the octane and (to a lesser extent) n-Hexadecane (HD) miniemulsions disappeared during polymerization leading to nanocapsules with a relatively narrow size distribution. We indeed showed that micellar nucleation could be neglected in our systems with 5～10 mmol/L aqueous solution of SDS. Homogenous nucleation only appeared in the system with high monomer contents.The morphology of latex particles could be controlled by manipulating the hydrolysis and condensation degree of MPS via changing the pH value of suspension. The portion of nanocapsules could be improved by increasing or decreasing pH value from the neutral condition, increasing the MPS weight content under basic condition, and introducing a suitable amount of crosslinker and NIPAM. The size of nanocapsules could be tuned by changing the SDS concentrations and monomer weight content in oil phase.
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