Simulation and experimental validation of the interplay between dielectrophoretic and electroosmotic behavior of conductive and insulator particles for nanofabrication and lab-on-chip applications

In this article, we investigated the different roles of dielectrophoresis (DEP) and AC electroosmosis (ACEO) phenomena in manipulating conductive and insulator particles as future fabrication and deposition technique. A computational model was implemented using the finite element method (FEM) to better understand the interplay and velocities caused by these two electrokinetic phenomena. The simulation results showed that Carbon Nanotubes (CNTs) experience positive DEP (pDEP) up to frequencies of 1 GHz, while polystyrene (PS) particles only showed negative DEP (nDEP) regardless of the frequency. The velocity due to the ACEO was significant at the electrodes’ level at low frequencies, especially between 100 Hz and 10 kHz. The simulation results were validated experimentally, where CNTs and PS were dispersed in a medium and subjected to non-uniform electric fields. The behavior and patterns the particles formed on planner interdigitated electrodes (IDEs) match with their trajectories from the simulation. At a frequency of 1 MHz, CNTs were attracted to regions with strong electric fields, while PS particles were repelled to regions with low electric fields indicating strong pDEP and nDEP, respectively. A cloud of particles was observed at 5 kHz, indicating strong ACEO at low frequencies. This study provides a simplified and reliable technique that can be applied to manipulate different types of particles for future multilayer fabrication, thin film deposition, and lap-on-chip applications.