From Microdroplets and Microfluidic Reactors to Functional Nanomaterials and Smart Surfaces
Yegân Erdem, University of California – Berkeley
Date: Wednesday, October 10, 2012
Place: EE 314 Seminar Room
Droplet-based microfluidic systems are promising for biological and chemical reactions as they provide rapid mixing times, precise concentrations and manipulation of samples as individual packages. These systems have several lab on a chip applications such as analysis of biological samples and synthesis of nanomaterials for sensor technology. Droplets can be either manipulated on surfaces by creating energy gradients or they can be transported inside microchannels by using a carrier fluid. In the first part of this talk, the manipulation of liquid droplets on surfaces by using texture ratchets will be discussed. In this technique, droplets can be moved selectively based on their volume and viscosity. The second part of this talk will focus on using droplet-based microfluidics to synthesize nanoparticles. These microfluidic reactors – or microreactors – show promise for the synthesis of nanoparticles with well controlled size, size distribution and shape. Compared to batch-wise synthesis techniques, microfluidic technology can provide precise control of the reaction conditions such as temperature, residence time and mixing ratio of reagents. Two different microreactors will be introduced. The first microreactor is made out of a polymer material and synthesizes magnetic iron-oxide nanoparticles by mixing two reagents at precise concentrations. The second microreactor is designed to produce monodisperse nanoparticles by utilizing thermally isolated heated and cooled regions for separating nucleation and growth processes. This reactor is made out of silicon and demonstrates the synthesis of TiO2 nanoparticles. At the end of this section, a method of assembling nanoparticles on a substrate will also be introduced. The third part of this talk will focus on the future directions of this research. Functionalizing nanomaterials by using microfluidic systems and creating smart surfaces with these functionalized nanomaterials for biosensing and energy harvesting applications will be discussed.