Varma, SC and Rajput, AS and Kumar, A (2022) Rheocoalescence: Relaxation Time through Coalescence of Droplets. In: Macromolecules, 55 (14). pp. 6031-6039.
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Abstract
The dynamics of the pendant drop coalescing with a sessile drop to form a single daughter droplet is known to form a bridge. The bridge evolution begins with a point contact between the two drops leading to a liquid neck of size comparable to the diameter of the drops. To probe this phenomenon in polymeric fluids, we quantify the neck radius growth during coalescence using high-speed imaging. In this study, we unveil the existence of three regimes on the basis of concentration ratio c/c*, namely, inertioelastic c/c∗ < ce/c*, viscoelastic ce/c∗ < c/c∗ < 20, and elasticity dominated regimes c/c∗ > 20. Our results suggest that the neck radius growth with time (t) obeys a power-law behavior tb, such that the coefficient b has a steady value in inertioelastic and viscoelastic regimes, with a monotonic decrease in elasticity dominated regime. On the basis of this dependence of b on concentration ratios, we propose a new measurement technique, rheocoalescence, which possibly can predict the relaxation time of these fluids in the elasticity dominated regime. We also show a deviation from universality proposed in the literature for the elasticity dominated regime.
| Item Type: | Journal Article |
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| Publication: | Macromolecules |
| Publisher: | American Chemical Society |
| Additional Information: | The copyright for this article belongs to the Author. |
| Keywords: | Coalescence; Drops; Elasticity; Flocculation; Ostwald ripening; Point contacts; Viscoelasticity, Concentration ratio; Daughter droplets; High speed imaging; Monotonic decrease; Pendant drop; Polymeric fluid; Power law behaviour; Radius growth; Sessile drops; Viscoelastics, Relaxation time |
| Department/Centre: | Division of Mechanical Sciences > Mechanical Engineering |
| Date Deposited: | 16 Sep 2022 05:10 |
| Last Modified: | 16 Sep 2022 05:10 |
| URI: | https://eprints.iisc.ac.in/id/eprint/76530 |
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