Single-step electropolymerization patterning of a polypyrrole nanowire by ultra-short pulses via an AFM cantilever

Nanotechnology. 2011 Jun 3;22(22):225303. doi: 10.1088/0957-4484/22/22/225303. Epub 2011 Apr 4.

Abstract

Conducting polymers (CPs) have attracted a great deal of attention due to their unique properties; these properties are useful in implementing various functional devices, such as memory, and chemical and biological sensors. In particular, the nanopatterning of CPs is a key technology that will accelerate the adoption of CPs in fabricating nanoscaled multifunctional devices. This paper presents an innovative technique for forming polypyrrole nanowire (PPy-NW) patterns, without any additional pretreatment on the gold surface, using atomic force microscopy (AFM) and ultra-short pulse voltage. Applying the ultra-short pulse voltage to the AFM tip has the following advantage: since the electrochemical current is extremely localized around the tip, the successful formation of CP nanowires results. This is because the pulse width is much shorter than the resistor-capacitor (RC) time constant of the equivalent electrochemical circuit of our experimental set-up. This paper provides systematic results regarding the dimensional variation of the PPy-NW patterns produced by varying the electrical conditions of the ultra-short pulse, such as the pulse amplitude, width, and frequency. The results show that use of an ultra-short pulse is essential in fabricating PPy-NW patterns. Additionally, an ultra-short pulse offers excellent pattern controllability for both width (353 nm ∼ 3.37 µm) and height (2.0 ∼ 88.3 nm).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electrochemical Techniques / methods*
  • Gold / chemistry
  • Microscopy, Atomic Force / methods*
  • Nanowires / chemistry*
  • Nanowires / ultrastructure
  • Polymerization
  • Polymers / chemistry*
  • Pyrroles / chemistry*

Substances

  • Polymers
  • Pyrroles
  • polypyrrole
  • Gold