Chemical gradients on graphene to drive droplet motion

ACS Nano. 2013 Jun 25;7(6):4746-55. doi: 10.1021/nn304267b. Epub 2013 May 16.

Abstract

This work demonstrates the production of a well-controlled, chemical gradient on the surface of graphene. By inducing a gradient of oxygen functional groups, drops of water and dimethyl-methylphosphonate (a nerve agent simulant) are "pulled" in the direction of increasing oxygen content, while fluorine gradients "push" the droplet motion in the direction of decreasing fluorine content. The direction of motion is broadly attributed to increasing/decreasing hydrophilicity, which is correlated to high/low adhesion and binding energy. Such tunability in surface chemistry provides additional capabilities in device design for applications ranging from microfluidics to chemical sensing.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Fluorine / chemistry
  • Graphite / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Motion*
  • Organophosphorus Compounds / chemistry
  • Oxygen / chemistry
  • Surface Properties
  • Water / chemistry

Substances

  • Organophosphorus Compounds
  • Water
  • dimethyl methylphosphonate
  • Fluorine
  • Graphite
  • Oxygen