Evaporation Dynamics of Mixed-Nanocolloidal Sessile Droplets

Pathak, Binita and Hatte, Sandeep and Basu, Saptarshi (2017) Evaporation Dynamics of Mixed-Nanocolloidal Sessile Droplets. In: LANGMUIR, 33 (49). pp. 14123-14129.

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Abstract

Evaporation dynamics of a particle-laden droplet has been a topic of interest in recent times owing to its widespread applications, ranging from surface patterning to drug delivery systems. The interplay of evaporation-induced internal flow dynamics, contact line dynamics, and nanoparticle self-assembly govern the morphologies of the residual structures. Finetuning of these residual structures is thus possible by controlling the governing parameters. A nanoparticle-laden sessile droplet placed on a hydrophobic substrate undergoes buckling phenomenon that results in a domelike structure with cavity on the surface. In the present work, it is shown that the addition of sodium dodecyl sulfate (SDS) surfactant in minute concentrations (0.005-0.02 wt %) can affect the contact line dynamics and subsequent buckling dynamics of a nanoparticle-laden droplet evaporating on a hydrophobic substrate. With increase in the initial SDS concentration, the morphologies of the residual structures show transition from a buckled dome structure to a flat flowerlike shape. Moreover, a critical SDS concentration (>0.0075 wt % in 20 wt % silica) is identified for the complete suppression of buckling instabilities. Last, the effects of droplet spreading on the surface crack dynamics are discussed.

Item Type:	Journal Article
Publication:	LANGMUIR
Publisher:	10.1021/acs.langmuir.7b03578
Additional Information:	Copy right for this article belongs to the Copyright © 2017 American Chemical Society
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	13 Jan 2018 07:14
Last Modified:	13 Jan 2018 07:14
URI:	http://eprints.iisc.ac.in/id/eprint/58577

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