Suppression of coffee ring: (Particle) size matters

Bansal, Lalit and Seth, Pranjal and Murugappan, Bhubesh and Basu, Saptarshi (2018) Suppression of coffee ring: (Particle) size matters. In: APPLIED PHYSICS LETTERS, 112 (21).

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Abstract

Coffee ring patterns in drying sessile droplets are undesirable in various practical applications. Here, we experimentally demonstrate that on hydrophobic substrates, the coffee ring can be suppressed just by increasing the particle diameter. Particles with larger size flocculate within the evaporation timescale, leading to a significant gravimetric settling (for Pe > 1) triggering a uniform deposit. Interestingly, the transition to a uniform deposit is found to be independent of the internal flow field and substrate properties. Flocculation of particles also alters the particle packing at the nanoscale resulting in order to disorder transitions. In this letter, we exhibit a physical exposition on how particle size affects morphodynamics of the droplet drying at macro-nano length scales. Published by AIP Publishing.

Item Type:	Journal Article
Publication:	APPLIED PHYSICS LETTERS
Publisher:	AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Additional Information:	Copy right of this article belong to AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	13 Jun 2018 15:26
Last Modified:	13 Jun 2018 15:26
URI:	http://eprints.iisc.ac.in/id/eprint/60001

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