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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Crystallization, Nucleation and Self Assembly II

CPP 28.4: Vortrag

Mittwoch, 13. März 2013, 16:00–16:15, H40

Nanoparticle Assembly in a modular Fluidic System — •Dominik Gerstner, Philip Born, and Tobias Kraus — Leibniz-Institut für Neue Materialien (INM), Campus D2.2, 66123 Saarbrücken

Nanoparticles are widely used in industrial and research applications. Agglomeration occurs in most use cases. We investigate structure formation during agglomeration to find which mechanisms govern the morphology of the agglomerates. For alkylthiol-stabilized gold nanoparticles with 6 nm core diameter, we found that the morphology depends crucially on the exact behavior of the ligand monolayer. Crystalline agglomerates only formed for a molten monolayer. Based on this study, we suggest that the particles’ microscopic packing is dominated by contact mechanics rather than colloidal interactions [1].

The ligands’ directing effect may be partially kinetic. We will discuss experiments to study agglomeration under defined mixing conditions and for different ligands efficiently. A modular fluidic system enables the preparation and direct observation of agglomerating nanoparticles in flow. Nanoparticle dispersion and agglomeration agent are merged in a micromixer. UV/Vis spectrometers or Light Scattering detectors subsequently provide characteristics of the growing agglomerates. The versatility of the setup allows rapid experimentation with a wide range of particles and conditions. Correlation of spectroscopic and real-space TEM data yields a detailed understanding of agglomerate morphologies. We use it to search for ligands that lead to agglomerates with predictable morphologies applicable in hybrid materials.

[1] T. Geyer et al. Phys. Rev. Lett. 109 (2012), 128302.