A Fundamental Study of Electrokinetic Instabilities to Manipulate and Self Assemble Nano- and Microparticles
Abstract
This is the final report for the US Army Research Office grant W911NF-16-1-0278, summarizing our results from May 2, 2016 through November 1, 2019. This research is based on our discovery that suspended 0.5 micro m diameter fluorescent polystyrene (PS) particles are attracted to, and accumulate near, the walls of a microchannel in combined Poiseuille and electroosmotic (EO) counterflow. This serendipitous observation is unexpected given that both the particle and channel surfaces are negatively charged. More surprising, these particles, after accumulating near the wall, assemble into periodic bands aligned with the flow (and electric field) direction above a minimum electric field magnitude |Emin| and, in most cases, a minimum shear rate ymin (Fig. 1). These bands, which we now know only exist within a few micro m of the (upper and lower) wall(s), are very elongated microstructures with cross sectional dimensions of micrometers and lengths of centimeters. Inspired by these discoveries, the objective of this research is to develop a fundamental understanding of how the dynamics and assembly of suspended colloidal particles with diameters of O(100 nm1 micro m) are impacted by the external electric fields and shear flow characteristic of Poiseuille and EO flows.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 02, 2020
- Accession Number
- AD1113929
Entities
People
- Minami Yoda
Organizations
- Georgia Tech Research Corporation