Characterization of polydopamine thin films deposited at short times by autoxidation of dopamine

Langmuir. 2013 Jul 9;29(27):8619-28. doi: 10.1021/la400587j. Epub 2013 Jun 27.

Abstract

Current interest in melanin films derived from the autoxidation of dopamine stems from their use as a universal adhesion layer. Here we report chemical and physical characterization of polydopamine films deposited on gold surfaces from stirred basic solutions at times ranging from 2 to 60 min, with a focus on times ≤10 min. Data from Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and electrochemical methods suggest the presence of starting (dopamine) and intermediate (C=N-containing tautomers of quinone and indole) species in the polydopamine films at all deposition times. A uniform overlayer analysis of the XPS data indicates that film thickness increased linearly at short deposition times of ≤10 min. At deposition times ≥10 min, the films appeared largely continuous with surface roughness ≈ ≤ 2 nm, as determined by atomic force microscopy (AFM). Pinhole-free films, as determined by anionic redox probe measurements, required deposition times of 60 min or greater.

Publication types

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

MeSH terms

  • Dopamine / chemistry*
  • Electrochemical Techniques
  • Gold / chemistry
  • Indoles / chemistry*
  • Microscopy, Atomic Force
  • Molecular Structure
  • Oxidation-Reduction
  • Polymers / chemistry*
  • Spectrophotometry
  • Spectroscopy, Fourier Transform Infrared
  • Surface Properties
  • Time Factors
  • X-Rays

Substances

  • Indoles
  • Polymers
  • polydopamine
  • Gold
  • Dopamine