Electrolyte-Mediated Assembly of Like-Charged Colloids

Project: Research project

Project Details


Colloidal assembly in solutions and at interfaces is a crucial process for synthesizing a wide-range of materials from photonic, to magnetic, to biological. The assembly of charged colloids in aqueous environments is often induced by high salt concentrations. However, the mechanisms for attractions between like-charged colloids at high salt concentrations are not fully understood. Theory and simulations show that for highly charged particles and for multivalent counterions, attractions of Coulombic origin arise due to positional correlations between the counterions associated with the neighboring particles. However, recent simulations show that for high salt concentrations, depletion-like attractions can induce colloidal aggregation. These attractions arise due to colloidal particles’ excluded volume for the clusters of ions, which are formed in the supporting electrolyte at high salt concentrations. However, there is a dearth of systematic experimental investigations that connect the ionic distribution surrounding particles and the structure of salt solution to electrolyte-mediated assembly. The proposed research has two objectives. First, experimentally deduce via X-ray scattering and spectroscopy, the structure of electrolyte solutions and the distribution of ions surrounding charged nanoparticles (NPs) and charged interfaces as a function of NP/interface charge, salt concentrations and the valence of the counterions (specific aim 1). The second objective is to develop a systematic method for the electrolyte-mediated assembly of NPs into different lattice types (specific aim 2).
Effective start/end date8/15/17 → 2/14/22


  • Department of Energy (DE-SC0018093)


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