Paper Number
PO122 

Session
Poster Session

Title
Delivering active motion to colloidal gels for microdynamics and mechanical rheometry measurements

Presentation Date and Time
October 17, 2018 (Wednesday) 6:30

Track / Room
Poster Session / Woodway II/III

Authors (Click on name to view author profile)

  1. Saud, Keara T. (University of Michigan, Materials Science and Engineering)
  2. Szakasits, Megan E. (University of Michigan, Chemical Engineering)
  3. Solomon, Michael J. (University of Michigan, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Keara T. Saud1, Megan E. Szakasits2, and Michael J. Solomon2
1Materials Science and Engineering, University of Michigan, Ann Arbor, MI; 2Chemical Engineering, University of Michigan, Ann Arbor, MI 48105

Speaker / Presenter 
Saud, Keara T.

Text of Abstract
We explore the effects of embedded active colloids in fractal cluster colloidal gels. These gels are a model system whose structure, dynamics, and rheology are all well characterized. Broadly, colloidal gels are a space-spanning network of particles arrested in a liquid because of strong and short-ranged attractive interactions. Control of the mechanical properties of gels is potentially applicable to industrial applications of gels including, paints and coatings, pharmaceuticals, or agricultural formulations. One potential strategy to tune the mechanical properties of gels is to use active matter– a field of non-equilibrium and self-propelling motion - in the gel. Active matter uses local gradients induced by asymmetric reactions, electric fields, light or other external fields to generate unique motion, such as spinning, swarming, and clustering. Here we embed active particles into colloidal gels to probe the effects on gel dynamics and rheological properties. Because current methods for delivery of active motion present challenges for rheological experiments, we introduce two different approaches to overcome these challenges for active colloidal gel systems. Specifically, we use two different mechanisms to generate active motion - self-diffusiophoresis induced by hydrogen peroxide and induced-charge electrophoresis generated with AC electric fields. Using the techniques we developed, we were able to measure the viscoelastic moduli of active colloidal gels. We find the addition of active motion into colloidal gels enhances the dynamics of the gel network, which has implications for the mechanical properties of the gel.