2025/11/25 by Coen I. Verschuur, Alexandros T. Oratis, Verschuur, Coen I. +6 · 1 voice
Engineering · Materials Science · #Fluid Dynamics and Heat Transfer #Fluid Dynamics and Mixing #Innovative Microfluidic and Catalytic Techniques Innovation #Polymer Foaming and Composites #Ultrasound and Cavitation Phenomena
paper · doi:10.1103/5sp3-k5l2
openalex publication_date 2026/06/01 · openalex created_date 2026/06/02 · openalex updated_date 2026/07/14
The pinch-off of bubbles in viscoelastic liquids is a fundamental process that has received little attention compared to viscoelastic drop pinch-off. While these processes exhibit qualitative similarities, the dynamics of the pinch-off process are significantly different. When a drop of a dilute polymer solution pinches off, a thread is known to develop that prevents breakup due the diverging polymer stresses. Conversely, our experiments reveal that this thread is absent for bubble pinch-off in dilute polymer solutions. We show that a thread becomes apparent only for high polymer concentrations, where the pinch-off dynamics become very sensitive to the size of the needle from which the bubble detaches. The experiments are complemented by numerical simulations and analytical modeling using the Oldroyd-B model, which capture the dilute regime. The model shows that polymer stresses are still singular during bubble pinch-off, but the divergence is much weaker as compared to drop pinch-off. This explains why, in contrast to droplets, viscoelastic bubble-threads do not appear for dilute suspensions but require large polymer concentrations