Paper Number
TM20                         My Program 

Session
Techniques and Methods: Rheometry, Tribometry, Spectroscopy and Microscopy

Title
Fast, cheap, and predictably wrong: Quantitative limits of tilted vial protorheology

Presentation Date and Time
October 22, 2025 (Wednesday) 4:25

Track / Room
Track 7 / Sweeney Ballroom D

Authors (Click on name to view author profile)

  1. Tiwari, Ramdas (University of Illinois Urbana-Champaign, Mechanical Science and Engineering)
  2. Armstrong, Connor D. (University of Illinois Urbana-Champaign, Beckman Institute for Advanced Science and Technology)
  3. Hossain, Mohammad Tanver (University Of Illinois Urbana-champaign, Mechanical Science and Engineering)
  4. Zakoworotny, Michael (University of Illinois Urbana-Champaign, Beckman Institute for Advanced Science and Technology)
  5. Arretche, Ignacio (University of Illinois Urbana-Champaign, Beckman Institute for Advanced Science and Technology)
  6. Sottos, Nancy R. (University of Illinois Urbana-Champaign, Beckman Institute for Advanced Science and Technology)
  7. Geubelle, Phillipe (University of Illinois Urbana-Champaign, Beckman Institute for Advanced Science and Technology)
  8. Tawfick, Sameh H. (University Of Illinois Urbana-champaign, Mechanical Science and Engineering)
  9. Ewoldt, Randy H. (University Of Illinois Urbana-champaign, Mechanical Science and Engineering)

Author and Affiliation Lines (in printed abstract book)
Ramdas Tiwari1, Connor D. Armstrong2, Mohammad Tanver Hossain2, Michael Zakoworotny2, Ignacio Arretche2, Nancy R. Sottos2, Phillipe Geubelle2, Sameh H. Tawfick2 and Randy H. Ewoldt1
1Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801; 2Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL 61801

Speaker / Presenter 
Tiwari, Ramdas

Keywords
experimental methods; theoretical methods; applied rheology; future of rheology; industrial applications; methods; non-Newtonian fluids; polymer blends; polymer solutions; rheometry; sustainability; techniques

Text of Abstract
We assess physics-based viscosity inference equations for the tilted vial test and propose criteria for when and why they fail.

High-throughput characterization of the mechanical properties of materials accelerates material discovery in both industrial and academic contexts. To this end, the tilted-vial test was proposed as a quick and cost-effective method for inferring viscosity [1]. While images of inverted vials of material are abundantly used in literature to indicate fluidity (or lack thereof), they are rarely used for the quantitative inference of properties [2]. The proposed test involves tilting a vial of material by a set angle and observing the evolution of the liquid-air interface. Driven by gravity and opposed by viscous effects, the interface levels out. Hossain et al. proposed a scaling law relating the timescale of this ‘leveling flow’ to the viscosity of the fluid. Importantly, this scaling law assumes ideal conditions (Newtonian flow and negligible inertial and surface tension effects), which are not always valid [3]. In this work, we predict when these assumptions break down and propose mathematical expressions for such limits. Pairing these with practical conditions on observable deformation rates and the maximum imposable shear stress fixes an operational window which serves as a quick and intuitive way to judge the reliability of inferred data. We validate the proposed operational window by comparing inferred viscosities with rheometer measurements and analyze the error variation with the Reynolds and Bond numbers. Our results show that the tilted vial test can accurately measure viscosities over several orders of magnitude and inference fails in a predictable fashion, thereby making it a candidate method for quantitative high-throughput characterization.

[1] Hossain et al.; J Rheol, (2024) DOI: 10.1122/8.0000667
[2] Lessard et al.; JACS, (2024) DOI: 10.1021/jacs.4c01578
[3] Hossain et al.; Curr Opin Colloid Interface Sci, (2024) DOI: 10.1016/j.cocis.2024.101866