Paper Number
MC7 

Session
Microfluidic and Confined Flows

Title
The role of molecular elasticity in sprayable yield-stress fluids

Presentation Date and Time
October 23, 2019 (Wednesday) 4:10

Track / Room
Track 4 / Room 305B

Authors (Click on name to view author profile)

1. Lin, Yu-Jiun (University of Delaware, Chemical and Biomolecular Engineering)
2. Horner, Jeffrey S. (University of Delaware, Chemical and Biomolecular Engineering)
3. Mourafetis, Christine (University of Delaware, Chemical and Biomolecular Engineering)
4. Illie, Brandon (Procter & Gamble)
5. Lynch, Matthew (Procter & Gamble, Corporate Functions)
6. Furst, Eric M. (University of Delaware, Chemical and Biomolecular Engineering)
7. Wagner, Norman J. (University of Delaware, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Yu-Jiun Lin¹, Jeffrey S. Horner¹, Christine Mourafetis¹, Brandon Illie², Matthew Lynch², Eric M. Furst¹, and Norman J. Wagner^1
1Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716; ²Corporate Functions, Procter & Gamble, Cincinnati, OH 45224

Speaker / Presenter 
Lin, Yu-Jiun

Text of Abstract
Consumer application attributes are often conflicting, such that molecular engineering can be necessary to yield a successful commercial product. A common example of conflicting attributes is the need for shelf and transportation stability in products comprised of suspensions of emulsions or colloids along with good shear stability, and controllable dissociation. These requirements necessitate rheological properties of a yield stress fluid with low elasticity at high shear rates. Nanostructured fluids where physical interactions provide both this desired yield-stress as well as strong shear-thinning and spayability are required. Rational design of complex fluids at the nanoscale enables formulation of such function-oriented, advanced materials and effective manufacturing processes. In this research, we study engineered, physically associating hydrogels using microfluidics, rheology, and small angle scattering technique to elucidate the role of nanoscale interactions and molecular elasticity in determining the relevant rheological properties. Mixed gums create self-healing and yield-stress structured fluids that are also sprayable. For contrast, a well-characterized, polyethylene oxide solution of varying Mw is similarly studied. An experimental platform composed of microfluidic hyperbolic contraction with pressure sensors probing both shear and extensional properties. Simultaneous microscopy enables flow velocimetry building a connection to the deformation history which can be incorporated into structure kinetic model to study contraction-stimulated alteration. Moreover, bulk rheology and neutron scattering complement the microfluidic flow behavior, providing important insights and connections between molecular structure, bulk properties, and the behavior under more complex flows.