Polarity Dependent Electrowetting for Directional Transport of Water through Patterned Superhydrophobic Laser Induced Graphene Fibers

Sujit Deshmukh, Debosmita Banerjee, Juan Sebastian Marin Quintero, Sam J. Fishlock, James McLaughlin, Prashant R. Waghmare, Susanta Sinha Roy

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
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Abstract

The possibilities of the precise control of wetting properties of a series of laser-induced graphene (LIG) films consisting of microscale air pockets on top of nano-scale surface roughness using electrowetting are demonstrated. By application of a marginal DC bias (∼2 V), water can efficiently wet as well as can be pumped through the superhydrophobic LIG substrates. Interestingly, the electrowetting phenomenon is strongly dependent on the applied voltage polarity and it causes an abrupt wetting transition from superhydrophobic (contact angle ∼152°) Cassie state to superhydrophilic (contact angle ∼7°) Wenzel state on the LIG films. By analyzing the voltage polarity dependent electrowetting results with an equivalent electrical circuit model at the solid-liquid interface, and considering the hierarchical dual surface roughness (micro-nano scale), the transition between the “slippy” Cassie state and the “sticky” Wenzel states is explained. Furthermore, we demonstrate that the unique structural characteristics of the custom-designed micropatterned LIGs, with precisely tailored surface energy by simple post-annealing treatment, enable easy preparation of superhydrophobic LIG films. The approach to prepare stable superhydrophobic LIG with voltage polarity dependent wetting mode transition is used here to controllably transport of water through 3D porous LIG surfaces.

Original languageEnglish
Pages (from-to)605-614
Number of pages10
JournalCarbon
Volume182
Early online date16 Jun 2021
DOIs
Publication statusPublished - 1 Sep 2021

Bibliographical note

Funding Information:
As a part of the University of Alberta’s Future Energy Systems research initiative, this research was made possible in part thanks to funding from the Canada First Research Excellence Fund (Project # T06P06 ). Also SD and PRW thank the Natural Science and Engineering Research Council ( NSERC ) for the financial support in the form of Grant No. RGPIN-2015-06542.

Publisher Copyright:
© 2021 Elsevier Ltd

Keywords

  • Electrowetting
  • Laser-induced graphene
  • Micropatterned
  • Superhydrophobic
  • Superhydrophilic
  • Water transport

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