Professor, University of Bordeaux, Centre de Recherche Paul Pascal/CNRS, France

Biography: Serge Ravaine obtained a PhD in Physical Chemistry in 1996. He was appointed Assistant Professor at Bordeaux University in 1997 and Full Professor in 2004. His research interests mainly concern the synthesis of colloidal particles (including patchy nanoparticles) and the fabrication of colloidal materials (including photonic colloidal crystals and optical metamaterials) by bottom-up approaches. He has supervised more than 20 PhD students and is co-author of more than 150 papers in international journals (h index: 36).

Speech Title: Novel patchy particles and their directional bonding
Aims: Compared to standard fabrication methods based on top-down approaches such as optical lithography, self-assembly offers the potential for easier fabrication and manipulation of nano- and microstructures, especially in three dimensions. In most cases, these building blocks may not naturally assemble into any desired structures. One emerging approach to confer particles predetermined "instructions" for assembly is to decorate the surface of the particles with "sticky patches" made, for example, of synthetic organic or biological molecules [1].

In this talk, we report on a new route to synthesize patchy particles with a controlled number of patches as well as on their use as building blocks for the elaboration of new structures with unusual morphology.

Methods: Our strategy is based on a seeded emulsion polymerization process leading to biphasic particles, which are composed of spherical silica spheres surrounded by a varying number of polystyrene nodules [2]. We succeeded in promoting the growth of the silica core of these biphasic particles. While growing, the silica surface conforms to the shape of the PS nodules. After the dissolution of the polystyrene nodules and functionalization of the dimples, homogeneous batches of particles with N well-located patches at their surface can be produced in large quantities.

Results: We will show that the assembly of the patchy particles offers the unique capability of creating new supraparticles. We will also show that we successfully derivatized them in unconventionally shaped particles, such as silica/gold multipod-like replicas [3], gold nanocages, etc.