【16th.July】Ligand-Directed Self-Assembly Of Nanoparticles
日期：2018-07-16
阅读：570
题目：Ligand-Directed Self-Assembly Of Nanoparticles
报告人：Bertrand Donnio，Research Director, 斯特拉斯堡大学与法国国家科研中心，
时间：7月16日 (周一), 下午2:00
地点： 化学楼五楼518会议室
邀请人：张绍东 特别研究员
摘要
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 smart and innovative applications. The collective optical and magnetic properties of such nanoparticles self-assemblies are strongly affected by their direct local environment and primarily depend on interparticle separations, symmetry of the periodic arrangements, and composition of the superlattices’ assemblies (single or multicomponent systems). Various strategies for NPs self-assembly have been considered so far. 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 representative 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 facilitate their assemblies into 2/3D superlattices, whereas the change in the dendritic generation allows for a precise and stepwise control of their separation. This offers potential for optimizing collective responses for applications including optical and magnetic. Dual mixing of dendronized hybrids further produces unprecedented AnBm binary superlattices of the Frank-Kasper type crystal phases, whose properties are intrinsically modulated at the nm-scale. Further, 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 direct method using polycatenar ligands for the synthesis of a wide variety of NPs. Self-assembly into single and binary NP superlattices demonstrates the excellent monodispersity of the so-produced NPs. These polycatenar ligands impose interparticle spacings and specific attractions, engineering self-assembly, which is tunable from hard sphere to soft sphere behavior.
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