Paper Number
AR13
Session
Applied Rheology and Rheology Methods
Title
Volatile dripping-onto-substrate (vDoS) extensional rheometry of polymeric fluids
Presentation Date and Time
October 11, 2021 (Monday) 5:00
Track / Room
Track 2 / Ballroom 7
Authors
- Robertson, Benjamin P. (University of Minnesota, Chemical Engineering and Materials Science)
- Calabrese, Michelle A. (University of Minnesota, Chemical Engineering and Materials Science)
Author and Affiliation Lines
Benjamin P. Robertson and Michelle A. Calabrese
Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55414
Speaker / Presenter
Robertson, Benjamin P.
Keywords
experimental methods; polymer solutions; rheology methods
Text of Abstract
Extensional flows of volatile, low-viscosity polymeric fluids are important in applications from spraying and roll-coating processes to fuel injection. Traditional extensional rheometers like the capillary breakup extensional rheometer (CaBER) are severely limited in their capability to study these fluids, due to their rapid breakup on the order of the plate separation time, inertial effects from pre-deformation, and solvent evaporation.1 The recently-developed dripping-onto-substrate (DoS) rheometry2 technique allows for measurement of lower viscosity samples in a single drop, reducing the use of expensive sample components and minimizing pre-deformation. However, the small drop volume exacerbates evaporation effects when volatile solvents are used, limiting the efficacy of DoS for measuring polymeric fluids formed in organic solvents. To address these challenges, we developed an environmental control chamber to substantially reduce the rate of evaporation in volatile DoS (vDoS) extensional rheometry. Using this system, we measure the extension of dilute solutions of high molecular weight PEO in several solvents of varying volatility and quality. By comparing parameters extracted from vDoS, including extensional relaxation time, at varying rates of evaporation, we validate this promising rheometric technique for use in a wider range of systems of interest. [1]Rodd, L. et al. Appl Rheol, 15.1 (2005): 12-27. [2]Dinic, J. et al. ACS Macro Lett, 4 (2015): 804-808.