Capillary-driven migration of droplets on conical fibers
A droplet placed on a hydrophilic conical fiber tends to move toward the end of larger radii due to capillary action. Experimental investigations are performed to explore the dynamics of droplets with varying viscosities and volumes on different fibers at the microscale. Droplets are found to accele...
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Main Authors | , , , , |
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Format | Journal Article |
Language | English |
Published |
03.09.2024
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Subjects | |
Online Access | Get full text |
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Summary: | A droplet placed on a hydrophilic conical fiber tends to move toward the end
of larger radii due to capillary action. Experimental investigations are
performed to explore the dynamics of droplets with varying viscosities and
volumes on different fibers at the microscale. Droplets are found to accelerate
initially and subsequently decelerate during migration. A dynamic model is
developed to capture dynamics of the droplet migration, addressing the
limitations of previous equilibrium-based scaling laws. Both experimental
results and theoretical predictions indicate that droplets on more divergent
fibers experience a longer acceleration phase. Additionally, gravitational
effects are pronounced on fibers with small cone angles, exerting a substantial
influence on droplet migration even below the capillary scale. Moreover,
droplets move more slowly on dry fibers compared to those prewetted with the
same liquid, primarily attributed to the increased friction. The experiments
reveal the formation of a residual liquid film after droplet migration on dry
fibers, leading to considerable volume loss in the droplets. To encompass the
intricacies of migration on dry fibers, the model is refined to incorporate a
higher friction coefficient and variable droplet volumes, providing a more
comprehensive depiction of the underlying physics. |
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DOI: | 10.48550/arxiv.2409.01822 |