Paper Number
PO71 

Session
Poster Session

Title
Active fractal gels of colloidal Janus spheres

Presentation Date and Time
October 8, 2014 (Wednesday) 6:05

Track / Room
Poster Session / Poster

Authors (Click on name to view author profile)

1. Szakasits, Megan E. (University of Michigan, Chemical Engineering)
2. Solomon, Michael J. (University of Michigan, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Megan E. Szakasits and Michael J. Solomon
Chemical Engineering, University of Michigan, Ann Arbor, MI

Speaker / Presenter 
Szakasits, Megan E.

Text of Abstract
We find that fractal gel networks of polystyrene colloids can be broken up by active motion of Janus colloids that have been incorporated into them. We synthesized Janus particles by electron beam deposition of platinum onto one micron carboxylate modified polystyrene particles. By adding the divalent salt magnesium chloride, an initially stable suspension of Janus colloids and polystyrene colloids, present in equal proportion, underwent aggregation to yield a fractal gel. The Janus colloids were activated by the addition of hydrogen peroxide. Changes in colloidal structure and dynamics were visualized by two channel confocal laser scanning microscopy (CLSM). By means of image analysis, we calculated the mean squared displacement (MSD) and radial distribution functions (RDF) of particles before and after addition of hydrogen peroxide. The MSD confirmed active motion of the synthesized Janus particles, and the RDF demonstrated how the addition of peroxide changed the gel structures by breaking the gel network up into clusters.