Model rules for the nucleation and growth of the nuclei. Initially, a varying number of nuclei are randomly distributed on the colloid surface. They grow according to three different scenario.
Hybrid organic-inorganic nanoparticles with well-controlled morphology are currently of great research interest. Synthetic routes leading to robust aggregates made of nanoparticles of different chemical natures which are associated in a controlled manner, i.e. number of nanoparticles and geometrical arrangement, are especially investigated. Clusters of spheres could mimic the space-filling models of simple molecules and are called “colloidal molecules”. In the framework of the TOCOMO ANR project, the strategy is based on a seeded-growth emulsion polymerization process leading to biphasic particles, which are composed of spherical silica spheres (50-400 nm) surrounded by a varying number of polystyrene (PS) nodules.
In the TOCOMO project, it was demonstrated that the key parameters to control the pod number and geometrical arrangement are (i) the volume ratio between silica seeds and PS nodules, (ii) the size of silica seeds and (iii) the silane grafting density. A key feature is that the synthetic process is reproducible, fast and can yield grams of biphasic submicronic particles up to 90% purity. In this project, the main contributions of the LIONS were to develop a reliable synthesis route to produce highly monodisperse silica seeds. Indeed, the size and size monodispersity of the silica seeds play a major role in the early nucleation stage of the process,,.
We have also developed a model predicting efficiently the obtained morphologies as a function of the synthesis parameters. The number and size of pods along time was also followed in situ using Small Angle Neutrons Scattering at D22 (ILL reactor). An initial step of rapid coalescence of the numerous PS nodules nucleating at the surface of the silica beads is followed by the growth of pods at a constant number per silica bead.
This project was supported by the Agence Nationale pour la Recherche
(contract # ANR-07-BLAN-0271).
 Fouilloux S, Desert A, Taché O, Spalla O, Daillant J, Thill A. , Journal of Colloid and Interface Science, 346, 79-86 (2010)
 Fouilloux S, Taché O, Spalla O, Thill A, Langmuir, 27(20) 12304-12311
 Fouilloux S, Daillant J, Thill A,. Colloids and Surfaces A, 393, 122-127(2012)
 Thill A, Désert A , Fouilloux S, Taveau JC, Lambert O, Lansalot M, Bourgeat-Lami E, Spalla O, Belloni L, Ravaine S and Duguet E, , Langmuir, 28(31), 11575-11583 (2012)