(283i) Investigating Droplet-Breakup Dynamics for Characterizing Low-Viscosity Elasticity of Dilute Polymer Solutions
AIChE Annual Meeting
Tuesday, November 15, 2016 - 10:30am to 10:45am
Similar to passive breakup of a droplet at a T-junction, a microfluidic device is presented that uses a cross-slot geometry to observe a two-phase droplet breakup process. For viscoelastic fluids, we report that a cylindrical filament forms between droplet segments, which decays exponentially in time. In optically tracking this decay, both transient extensional viscosity and relaxation times were evaluated. For validating and optimizing the device, a range of polyethylene oxide (PEO) and Newtonian solutions were tested. Comparisons of the evolution profiles due to the presence of elasticity were made. The resulting Trouton ratios versus Hencky strains were recorded and compared with the results from other emerging extensional techniques. Experiments were performed to observe the growth of instability, the dynamics of filament thinning, and the presence of any bead formation in the droplet breakup event. These results reveal a complex interplay between viscous, elastic, capillary, and inertial contributions in the extensional devices used.