|
Derek Halverson
Advisor: Gennady Friedman, Ph.D.
Abstract:
Colloidal systems are an area of increasing interest with biomedical to industrial applications. In the majority of these systems, especially at the research level, monodispersity is desired. However existing methods for creating a monodisperse system or fractionating a polydisperse system into a monodisperse one are often painfully slow, have trouble scaling up, or have troubles with specific systems. This work proposes and demonstrates a method of fractionating colloidal systems by controlling, which sizes of particles will flocculate (cluster together) by varying an external magnetic field. This is done by adding iron oxide nanoparticles (ferrofluid) to the continuous phase of the system, which allows the non-magnetic particles to be manipulated by the external field. The ferrofluid can later be removed by existing methods.
Additionally applications for these monodisperse systems, which inspired the above work to create a fast easy fractionation method, are demonstrated. These include: moving colloidal particles around on a surface for delivery to a specific region, trapping particles for study or for reactions, using concentrated clusters of emulsions droplets to protect regions on a surface from chemicals, and causing self assembled clusters to "swim" in bulk.
Tuesday, May 8th, 11:00 a.m.
Randell 238A
|
