Paper Number
IR12                         My Program 

Session
Interfacial Rheology, Surfactants, Foams and Emulsions

Title
Characterizing yield stress mechanisms in particle laden interfaces

Presentation Date and Time
October 20, 2025 (Monday) 3:45

Track / Room
Track 5 / O’Keeffe + Milagro

Authors (Click on name to view author profile)

  1. Bhaskar, KC (Texas Tech University)
  2. Rogers, Simon A. (University of Illinois Urbana-Champaign, Chemical and Biomolecular Engineering)
  3. Christopher, Gordon F. (Texas Tech University)

Author and Affiliation Lines (in printed abstract book)
KC Bhaskar1, Simon A. Rogers2 and Gordon F. Christopher1
1Texas Tech University, Lubbock, TX 79410; 2Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801

Speaker / Presenter 
Bhaskar, KC

Keywords
colloids; emulsions; interfacial rheology

Text of Abstract
Particle Laden interfaces exhibit complex yielding behavior that has previously been identified but not sufficiently characterized. We use a unique combination of rheological and microstructural analysis to further investigate the yielding behavior of densely packed, particle-laden, air–water interfaces. Specifically, using a custom base with a double wall ring geometry, interfacial viscoelastic moduli were measured by extending the time resolved strain decomposition technique for bulk materials proposed by Donley et al [PNAS, 2020; 117:21945] and the microstructure was examined via tracking of interfacial particles.

Our results reveal that the G? overshoot originates from a peak in G?solid, followed by the growth of G?fluid, marking the transition from elastic energy storage to irreversible microstructural rearrangement, which has been similarly observed in bulk soft glass like materials. From particle tracking, we measure the accumulation of non-recoverable strain in the microstructure as well as the development of fractures in the interface. The accumulation of microstructural strain at the particle level is correlated to the rheometric strain, allowing us to identify the microstructural events that lead to the observed evolution of the decomposed G”.