The Role Of Conductivity On Instabilities Of Ferrofluids In Microchannels

Zachary Johnson

School Name

Governor's School for Science and Math

Grade Level

12th Grade

Presentation Topic

Physics

Presentation Type

Mentored

Mentor

Mentor: Dr. Xuan; Department of Mechanical Engineering, Clemson University

Oral Presentation Award

2nd Place

Abstract

The process of creating instabilities with ferrofluids (water-based solutions that contain magnetic nanoparticles) via lab-on-a-chip devices has proved to be very efficient for mixing solutions on a microscopic scale. The compact size of these chips enables easy transport, and can lead to various cost-effective medical applications. Studies have already been carried out to create electrokinetic instabilities using ferrofluids and deionized (DI) water in a T-shaped microchannel. These instabilities occur at the interface of the channel and form finger-like structures as the fluids continue to flow because the solutions react differently to the applied electric field. This experiment shows that the levels of conductivity of the solutions are critical to maintaining the instabilities at low voltages, and therefore low temperatures. By increasing the concentration of the ferrofluid, thus giving it a higher level of conductivity than the DI water in the channel, lower threshold electric field-induced instabilities were created. The ability to form instabilities at low voltages allows for rapid microfluidic mixing without damaging the channel which may occur due to the joule-heating effect resulting from higher voltages. This experiment has led to further studies regarding the joule-heating effect on micro channels. Specifically, whether or not joule heating inhibits instabilities from forming, or if it forms thermal instabilities at higher temperatures.

Location

Owens 104

Start Date

4-16-2016 10:00 AM

COinS
 
Apr 16th, 10:00 AM

The Role Of Conductivity On Instabilities Of Ferrofluids In Microchannels

Owens 104

The process of creating instabilities with ferrofluids (water-based solutions that contain magnetic nanoparticles) via lab-on-a-chip devices has proved to be very efficient for mixing solutions on a microscopic scale. The compact size of these chips enables easy transport, and can lead to various cost-effective medical applications. Studies have already been carried out to create electrokinetic instabilities using ferrofluids and deionized (DI) water in a T-shaped microchannel. These instabilities occur at the interface of the channel and form finger-like structures as the fluids continue to flow because the solutions react differently to the applied electric field. This experiment shows that the levels of conductivity of the solutions are critical to maintaining the instabilities at low voltages, and therefore low temperatures. By increasing the concentration of the ferrofluid, thus giving it a higher level of conductivity than the DI water in the channel, lower threshold electric field-induced instabilities were created. The ability to form instabilities at low voltages allows for rapid microfluidic mixing without damaging the channel which may occur due to the joule-heating effect resulting from higher voltages. This experiment has led to further studies regarding the joule-heating effect on micro channels. Specifically, whether or not joule heating inhibits instabilities from forming, or if it forms thermal instabilities at higher temperatures.