Subject: Reminder -K. Hess Seminar, Wed. 7/11, 9:00 AM, ARMS Rm 1109
From: "Stacey, Lisa A" <[email-masked]>
To: "[email-masked]'" <[email-masked]>, "[email-masked]'" <[email-masked]>
Date: Tue, 10 Jul 2012 14:19:13 -0400

MATERIALS SCIENCE AND ENGINEERING
SEMINAR

Generation of Colloidal Granules and Capsules from Double Emulsion Drops

by

Kathryn Hess
Ph.D. Final Exam
Advisor:  Prof. C. Martinez

ABSTRACT

Assemblies of colloidal particles are extensively used in ceramicprocessing, pharmaceuticals, inks and coatings.  In this project, the aim was to develop a new technique to fabricate monodispersed colloidal assemblies.  The use of microfluidic devices and emulsion processing allows for the fabrication of complex materials that can be used in a variety of applications.  A microfluidic device is used to create monodispersed water/oil/water (w/o/w) double emulsions with interior droplets of colloidal silica suspension ranging in size from tens to hundreds of microns.  By tailoring the osmotic pressure using glycerol as a solute in the continuous and inner phases of the emulsion, we can control the final volume size of the monodispersed silica colloidal crystals that form in the inner droplets of the double emulsion.  Modifying the ionic strength in the colloidal dispersion can be used to affect the particle-particle interactions and crystal formation of the final colloidal particle.

This w/o/w technique has been used with other systems of metal oxide colloids and cellulose nanocrystals.  Encapsulation of the colloidal suspension in a polymer shell for the generation of ceramic-polymer core-shell particles has also been developed. These core-shell particles have spawned new research in the field of locally resonant acoustic metamaterials.

Systems and chemistries for creating cellulose hydrogels within the double emulsions have also been researched.  Water in oil single emulsions and double emulsions have been used to create cellulose hydrogel spheres in the sub-100 micron diameter range.  Oil/water/oil double emulsions allow us to create stable cellulose capsules.  The addition of a second hydrogel polymer, such as acrylate or alginate, further strengthens the cellulose gel network and can also be processed into capsules and particles using the microfluidic device. This work could have promising applications in acoustic metamaterials, personal care products, pharmaceuticals, and agricultural applications, among others.

Date:   Wednesday, July 11, 2012

Time:        9:00 A.M.
Place:   ARMS 1109

Lisa Stacey
Secretary/Development Assistant
Purdue University
School of Materials Engineering
765/494-4100