Abecassis, Benjamin (2006) Probing gold nanoparticles nucleation and growth in situ. PhD thesis LIONS/CEA, LIONS/CEA, EP/X p.188.
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Abstract
In this thesis, we assess the formation mecanism of gold nanoparticles in situ in liquid media (homogeneous or in microemulsion) by small angle scattering techniques. The first part details several important concepts which are useful for an appropriate understanding of the rest of the thesis along with an overview of the literature on the subject. We then present results of time resolved synchrotron small angle X ray scattering and UV-visible experiment performed in situ during the formation of gold nanoparticles in organic solvent. We show that it is possible to follow the nucleation and growth of the particles in real time with a time resolution of a few hundreds milliseconds. We show that depending on the chemi!
cal nature of the ligand the nucleation and growth can be eith!
er simu ltaneous or separated in time. In the latter cas, the growth is limited by surface reaction of the monomer at the particule’s surface. We also show that when the produced nanoparticles have an average radius larger than 5 nm, they self-assemble into ordered super-lattice which exhibit a cubic face center cristallographic structure.
In a third part, by using a combination of complementary techniques we study water/oil/octylammoniumoctanoate microemulsions in the reverse micelles part of the phase diagram. The structure of these ''catanionic'' microemulsions are revealed as a function of the water content, the temperature and the surface charge. The different observed topologies (sphere, rodlike or connected wormlike) and the phase transitions are compared to a recent theory which takes into account the curvature energy of the surfactant film. Finally, we show that these microemulsions can be used efficiently to synthesise gold nanoparticles. We show that the template effect, often cited to explain the formation of nanoparticles in reverse
| Item Type: | PhD Thesis (PhD) |
|---|---|
| Thesis Supervisor: | Testard, Fabienne |
| Date: | November 2006 |
| Board of examiners: | Porte, Grégoire and Chaudret, Bruno and Sanchez, Clément and Barboux, Philippe |
| Ecole Doctorale: | ED 447 ECOLE DOCTORALE DE L'ECOLE POLYTECHNIQUE |
| Discipline: | LIONS/CEA |
| Collection (Fonds): | EP/X |
| Institution: | EP/X |
| Department: | LIONS/CEA |
| Subjects: | 6. Chemistry, Physical Chemistry and Chemical Engineering |
| Uncontrolled Keywords: | Nanoparticles, Gold, Small angle scattering, Microemulsion, Surfactant, Nanoparticules, Or, Diffusion aux petits angles, Microémulsions, Tensioactifs |
| ID Code: | 2411 |
|---|---|
| Deposited By: | Laurence Vidament |
| Deposited On: | 02 May 2007 |
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