Paper Number
PO29 

Session
Poster Session

Title
Role of substrate spreading and dimensionless volume on Dripping-onto-Substrate measurements of low viscosity solutions

Presentation Date and Time
October 12, 2022 (Wednesday) 6:30

Track / Room
Poster Session / Riverwalk A

Authors (Click on name to view author profile)

  1. Lauser, Kathleen T. (University of Minnesota, Chemical Engineering and Materials Science)
  2. Zhang, Diana Y. (University of Minnesota, Chemical Engineering and Materials Science)
  3. Rueter, Amy (University of Minnesota, Chemical Engineering and Materials Science)
  4. Robertson, Ben P. (University of Minnesota, Chemical Engineering and Materials Science)
  5. Luong, Romy (University of Minnesota, Chemical Engineering and Materials Science)
  6. Calabrese, Michelle A. (University of Minnesota, Chemical Engineering and Materials Science)

Author and Affiliation Lines (in printed abstract book)
Kathleen T. Lauser, Diana Y. Zhang, Amy Rueter, Ben P. Robertson, Romy Luong and Michelle A. Calabrese
Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455

Speaker / Presenter 
Lauser, Kathleen T.

Keywords
experimental methods; bio-fluids; polymer solutions; surfactants

Text of Abstract
Dripping onto substrate (DoS) extensional rheology measures the capillary-driven thinning of a liquid bridge to obtain extensional flow properties of a variety of fluids, such as polymer, micellar, and protein solutions. Compared to other capillary-driven flow techniques such as CaBER which applies a step stretch to the fluid, DoS can measure lower viscosity fluids and imposes less pre-deformation, which can affect fluid microstructure. However, while CaBER has a relatively well-understood operating space1, the analogous understanding of instrument parameters on DoS measurements is lacking, as the unstable liquid bridge is generated via substrate spreading. Here, we explore the effects of DoS parameters such as spreading on the substrate and volume of the liquid bridge on measurement reproducibility using model protein, poloxamer, and polysorbate fluids. Changing spreading on the substrate, which can be manipulated using untreated and hydrophilic coated slides, can change duration of thinning and emergence of elastic behavior. Additionally, using a series of experiments with different aspect ratios and slide types, we show the relative effects of substrate spreading and liquid bridge volumes on measurements, two parameters that are challenging to decouple. Understanding volume and spreading effects leads to more consistent DoS measurements and more accurate comparisons between DoS trials.

  1. Meseguer, J.; Slobozhanin, L. A.; Perales, J. M. Advances in Space Research 1995, 16 (7), 5–14.