Paper Number
PG7 

Session
Polyelectrolytes, Self-assembling Systems & Gels

Title
Tuning the structure and rheology of nanoemulsion colloidal gels through screening of electrostatic interactions and thermoresponsive polymer bridging

Presentation Date and Time
October 16, 2018 (Tuesday) 4:35

Track / Room
Track 3 / Bellaire

Authors (Click on name to view author profile)

  1. Cheng, Li-Chiun (Massachusetts Institute of Technology)
  2. Vehusheia, Signe Lin Kuei (ETH Zürich)
  3. Doyle, Patrick S. (Massachusetts Institute of Technology, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Li-Chiun Cheng1, Signe Lin Kuei Vehusheia2, and Patrick S. Doyle3
1Massachusetts Institute of Technology, Cambridge, MA 02139; 2ETH Zürich, Zurich, Switzerland; 3Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142

Speaker / Presenter 
Cheng, Li-Chiun

Text of Abstract
Self-assembly of colloidal gels is intimately related to the interparticle potential. Particle attraction triggered by thermally-responsive polymer bridging is a powerful method to externally modulate the interparticle potential in time and thus finely control the resulting arrested states. It is desirable to design systems which are responsive to multiple stimuli for refined material property control and advanced applications. In this work, we study the rheological properties and the microstructures of a model oil-in-water nanoemulsion system developed by our group where the aggregation of the droplets is controlled by the interplay of inter-droplet polymer bridging, depletion attraction, and electrostatic repulsion. The nanoemulsion system allows us to independently trigger the colloidal self-assembly by varying the ionic strength and/or the temperature. We carefully manipulate the interparticle potentials through depletion attraction, electrostatic repulsion and interdroplet bridging. We show how sequential application of external stimuli can be used to tune rheological properties and microstructures. We also provide a molecular understanding of the underlying mechanisms at play.