Cette conférence sera prononcée par le professeur Matthew Moffitt du Département de chimie de l'University of Victoria. Elle sera donnée en anglais.
Résumé : Emerging strategies for assembling inorganic nanoparticles into ensembles with multiscale organization are establishing a new paradigm for the synthesis of devices and functional materials with applications ranging from drug-delivery to photonics. In our lab, we develop a combination of bottom-up and top-down approaches to generating hierarchical colloids of functional inorganic nanoparticles and polymers with structural control. In one general strategy, 'smart nanoparticles' are designed with surface characteristics that mimic molecular amphiphiles. We will discuss a recent example from our group in ionic block copolymer self-assembly that provides the inspiration and design strategy for nanoparticle building blocks with the essential chemical and conformational features of ionic block copolymer chains in aqueous media. Inorganic nanoparticles with surface-tethered mixed brushes of hydrophobic and chargeable hydrophilic chains are shown to self-assemble in polar solvent mixtures into unprecedented hierarchical superstructures analogous to known ionic block copolymer aggregates, but with complex organizations of nanoparticles in three dimensions. A second strategy focuses on directing self-assembly from the top-down using external force fields. Specifically, we have studied how tuneable shear-fields in microfluidic reactors can provide control over shape, size and polydispersity of colloidal aggregates of nanoparticles and block copolymers. By virtue of confined volumes and extremely high shear fields, the microfluidic environment provides a new 'processing handle' on molecular level self-assembly, allowing structure to be controlled using top-down parameters such as flow rate for a given set of chemical conditions.