Hierarchical liquid marbles formed using floating hydrophobic powder and levitating water droplets

Pritam Kumar Roy; Bernard P Binks; Shraga Shoval; Leonid A Dombrovsky; Edward Bormashenko

doi:10.1016/j.jcis.2022.06.168

Hierarchical liquid marbles formed using floating hydrophobic powder and levitating water droplets

J Colloid Interface Sci. 2022 Nov 15:626:466-474. doi: 10.1016/j.jcis.2022.06.168. Epub 2022 Jul 1.

Authors

Pritam Kumar Roy¹, Bernard P Binks², Shraga Shoval³, Leonid A Dombrovsky⁴, Edward Bormashenko⁵

Affiliations

¹ Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel.
² Department of Chemistry, University of Hull, Hull HU6 7RX, UK.
³ Department of Industrial Engineering and Management, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel.
⁴ Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel; Heat Transfer Laboratory, Joint Institute for High Temperatures, 111116 Moscow, Russia; Microhydrodynamic Technologies Laboratory, X-BIO Institute, University of Tyumen, 625003 Tyumen, Russia.
⁵ Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel. Electronic address: edward@ariel.ac.il.

PMID: 35803145
DOI: 10.1016/j.jcis.2022.06.168

Abstract

Hypothesis: Liquid marbles i.e. droplets coated by hydrophobic particles may be formed not only on the solid substrates but also on the floating layers of hydrophobic powders such as fluorinated fumed silica or polytetrafluoroethylene.

Experiments: Formation and growth of liquid marbles on fluorinated fumed silica or polytetrafluoroethylene powder floating on a heated water-vapor interface is reported. Marbles emerge from condensation of water droplets levitating above the powder layer.

Findings: The kinetics of the growth of droplets is reported. Growth of droplets results from three main mechanisms: water condensation, absorption of small droplets and merging of droplets with neighboring ones. Growing droplets are coated with the hydrophobic powder, eventually giving rise to the formation of stable liquid marbles. Formation of hierarchical liquid marbles is reported. Growth of liquid marbles emerging from water condensation follows the linear temporal dependence. A phenomenological model of the liquid marble growth is suggested.

Keywords: Condensation; Fluorinated fumed silica; Levitation; Liquid marbles; Water droplets.