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Seminar Bertrand DONNIO

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Ligand-Directed Self-Assembly of Nanoparticles

jeudi 21 décembre 2017, 10h, salle 907, sous-sol du bâtiment 10 C

contact: Joëlle RAULT-BERTHELOT (3 59 64) et Cyril PORIEL (3 59 77)

Abstract :

Ligand-Directed Self-Assembly Of Nanoparticles

E. Terazzi,† G. Nealon,† S. Buathong,† R. Gréget,† A. Graviluta,† T. Selvam,† C. Dominguez,† D. Jishkariani,‡ Katherine C. Elbert, ‡ B. T. Diroll,‡ M. Cargnello,‡ L. Malassis,‡ C. B. Murray,‡ J.L. Gallani,† B. Donnio†,*

U PENN-SOLVAY (USA)‡ & IPCMS (France)†

*Corresponding author: bdonnio@ipcms.unistra.fr

Self-assembly of nanoparticles (NPs) into periodic superlattices is of relevance for engineering materials with new, tunable and reconfigurable functions, and are therefore much sought after for the emergence of innovative applications. The collective physical properties of NPs (especially optical and magnetic) and their interactions with the environment (sound, EM waves) are strongly modified when organized into such superlattices, and are essentially controlled by the symmetry, the nature (single or multicomponent systems) and the interparticular separations. Various strategies for NPs self-assembly have been developed so far with more or less success. We are currently developing a bottom-up chemical route for the fabrication of NP superlattices, whose self-assembly is directed by the surface functionalization (ligand shell) of the NPs. Illustrated by some examples, we will show how the ligand shell affects both self-assemblies and certain other physical properties.
i) Dendritic ligands of several generations tethered to the surface of NPs allow the control of their assemblies into 2/3D superlattices, whereas the change in the dendritic generation allows for a precise and stepwise control of NP separation. This offers potential for optimizing collective responses for applications including optical and magnetic. Dual mixing of dendronized species further produces unprecedented binary superlattices, whose properties are intrinsically modulated at the nm-scale. Multifunctionality in dendrons is readily achieved and leads to unique and original patchy NPs, with modulable surface and self-assembly properties.
ii) Hydrophobic colloidal NPs are mainly synthesized and manipulated with commercially available ligands. These remain invaluable but surface functionalization is typically limited to a small number of molecules. We have recently proposed a robust method using polycatenar ligands for the direct synthesis of a wide variety of monodisperse NPs. Self-assembly into single and binary NP superlattices demonstrates the excellent monodispersity of the so-produced NPs. In addition, some NPs self-assemble into bcc lattices that deviate from conventional close-packed structures (fcc or hcp) formed by the same NPs coated with commercial ligands. These polycatenar ligands impose interparticle spacings and specific attractions, engineering self-assembly, which is tunable from hard sphere to soft sphere behaviour.
Polycatenar and dendritic molecules therefore offer versatile and modular platforms for the development of ligands with targeted properties, bringing organic functionality to inorganic NCs. This subsequently controls aspects such as solubility, wettability, interparticle spacings, self-assembly, liquid crystalline behaviour, biological and physical properties. It is expected that structural complexities and practical utilities be achieved through a thoughtful exploitation of organic chemistry and expanded to various inorganic systems.

Agenda

  • Thursday 21 December 10:00-11:00 -

    Seminar Bertrand DONNIO

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