Dielectrophoresis of nanocolloids: a molecular dynamics study

TL;DR

This study uses molecular dynamics simulations to explore dielectrophoresis of nanocolloids, revealing how particle mobility varies with temperature and electric field, providing insights into nanoscale particle manipulation.

Contribution

First molecular dynamics simulation of nanocolloid dielectrophoresis, modeling particles with a macroion and microions in explicit solvent to analyze DEP behavior.

Findings

Particle drift velocities are proportional to DEP force.

DEP mobility exhibits time dependence, indicating changing friction.

Weak temperature dependence of DEP displacements observed.

Abstract

Dielectrophoresis (DEP), the motion of polarizable particles in non-uniform electric fields, has become an important tool for the transport, separation, and characterization of microparticles in biomedical and nanoelectronics research. In this article we present, to our knowledge, the first molecular dynamics simulations of DEP of nanometer-sized colloidal particles. We introduce a simplified model for polarizable nanoparticles, consisting of a large charged macroion and oppositely charged microions, in an explicit solvent. The model is then used to study DEP motion of the particle at different combinations of temperature and electric field strength. In accord with linear response theory, the particle drift velocities are shown to be proportional to the DEP force. Analysis of the colloid DEP mobility shows a clear time dependence, demonstrating the variation of friction under non-equilibrium. The time dependence of the mobility further results in an apparent weak variation of the DEP displacements with temperature.