Sequential tasks performed by catalytic pumps for colloidal crystallization

TL;DR

This paper demonstrates how catalytic pumps can sequentially manipulate colloids through electric fields and fluid flows, enabling tasks like repulsion, attraction, and guided crystallization by controlling local proton concentrations.

Contribution

It introduces a method for sequential colloidal manipulation using catalytic pumps, highlighting the role of proton concentration in task switching.

Findings

Catalytic pumps can perform multiple colloidal tasks sequentially.

Task switching is controlled by local proton concentration changes.

The approach enables programmable colloidal assembly processes.

Abstract

Gold-platinum catalytic pumps immersed in a chemical fuel are used to manipulate silica colloids. The manipulation relies on the electric field and the fluid flow generated by the pump. Catalytic pumps perform various tasks, such as the repulsion of colloids, the attraction of colloids, and the guided crystallization of colloids. We demonstrate that catalytic pumps can execute these tasks sequentially over time. Switching from one task to the next is related to the local change of the proton concentration, which modifies the colloid zeta potential and consequently the electric force acting on the colloids.