Asymmetric rectified electric and concentration fields in multicomponent electrolytes with surface reactions

Area of Science:

• Colloid and Interface Science
• Electrochemical Systems
• Theoretical Physics

Background:

• Experimental colloidal assembly uses AC fields and electrochemistry in multicomponent electrolytes.
• Theoretical models have been limited to binary electrolytes and ignored electrochemical reactions.

Purpose of the Study:

• To theoretically investigate colloidal assembly in multicomponent electrolytes with electrochemical reactions.
• To analyze the impact of non-ideally blocking electrodes and surface reactions.

Main Methods:

• Regular perturbation analysis in the low-applied-potential regime.
• Solving Poisson-Nernst-Planck equations for electrical potential and ion concentrations.
• Utilizing numerical and analytical calculations.

Main Results:

• Electrochemical reactions alone generate asymmetric rectified electric fields (AREFs), independent of diffusivity contrast.
• AREFs from electrochemical reactions can be stronger than those from diffusivity differences.
• Asymmetric rectified concentration fields (ARCFs) emerge, supporting electrodiffusiophoresis.

Conclusions:

• Electrochemical reactions are a primary driver for AREFs and ARCFs in colloidal assembly.
• Ionic strength and charge density imbalances are crucial for AREF and ARCF formation.
• Findings advance understanding of colloidal assembly and electrolyte transport in electrochemical devices.