Paper Number
GG16 

Session
Out of Equilibrium Systems: Gels and Glasses

Title
Accelerated gelation kinetics in binary colloidal gels of two different attraction strengths

Presentation Date and Time
October 22, 2019 (Tuesday) 10:15

Track / Room
Track 7 / Room 306C

Authors (Click on name to view author profile)

1. Cho, Jae Hyung (Massachusetts Institute of Technology, Mechanical Engineering)
2. Bischofberger, Irmgard (Massachusetts Institute of Technology, Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Jae Hyung Cho and Irmgard Bischofberger
Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA

Speaker / Presenter 
Cho, Jae Hyung

Text of Abstract
When two types of colloids of different attraction strengths are mixed, the resulting gel displays linear viscoelastic moduli and a relaxation time that fall in-between those of the gels formed by the two individual types. By using differential dynamic microscopy (DDM), however, we find that, at the microscale, the binary gels evolve in a way that is not intermediate between the kinetics of the individual systems; the characteristic time scale of thermal fluctuation in a mixed gel reaches its steady state more rapidly than in either individual system at the same total particle volume fraction. Employing the thermal sensitivity of our home-made polystyrene-poly(N-isopropylacrylamide) core-shell particles, we systematically study the dynamics of the binary gels at different mixing proportions, both during and after the network formation. We explore how the discrepancy could be resolved by unravelling the governing parameters of the dynamics that we capture in DDM.