Chiral nanoparticles: preparation and studies of their optical properties and self-assembly into functional nanocomposite materials

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Chirality is an inherent property of all objects, be they macroscopic, such as right and left hands, or microscopic, like molecules. Chirality is very important in chemistry since most natural molecules are chiral. Yet, chirality still remains largely underexplored at the nanoscale, and especially for nanoparticles. Understanding and controlling nanoparticle chirality is of fundamental importance and will immediately impact applications of chiral materials in catalysis and biosensors. The aspiration of the proposed research is to discover and study efficient routes of preparation of chiral nanoparticles. Attaining control over nanoparticle chirality and combining it with control over size, polydispersity and surface functionalities of nanoparticles will enable their applications as chiral building blocks for nanocomposite materials with tunable functional properties. Recently, gold nanoparticles featuring prominent chirality and colloidal stability have been produced in my laboratory. At the current stage of our research, the mechanisms of chiral nanoparticle formation are to be investigated in detail. Most nanoparticles display size-dependent optical properties ("quantum size" effect), so the combination of Raman and UV-Vis microspectroscopy will be used for sensitive in-situ monitoring of nanoparticle formation. We will also explore self-assembly of chiral nanoparticles and their incorporation into suitable matrices to produce novel composite materials with controlled chirality and nanoscale architecture. Such materials are promising in advanced optical applications, e.g. metamaterials.  Materials with controlled chirality, surface functionality and selective optical responses are a natural choice for biosensors. They can be tailored to detect a very small number of target molecules, since nanoparticle properties are much more sensitive to surface changes compared to bulk materials. Chiral nanoparticles are advantageous for enantioselective catalysis, where the current thrust is to efficiently synthesize molecules similar to natural compounds. Accordingly, our research will be directed to produce nanocomposite materials for catalysts and sensors.