Wydział Chemii

Bartosz Mądry

Maria Grzeszczuk

Klaus Wandelt

Marek Nowicki

2017

Journal of Electroanalytical Chemistry

786

154-163

10.1016/j.jelechem.2017.01.017

Naukowa

Angielski

Artykuł

The early stages of electrodeposition of polypyrrole (PPy) on an Au(111) surface are studied using in-situ scanning tunneling microscopy under the electrochemical control of the process. Shape, size, nucleation density and dimensionality of the early growth of the polymer phase was of interest. Electropolymerization took place in aqueous electrolytes containing multicharged anions. The diameter of the smallest detected surface particulates was of the order of a few Å in Na₃AlF₆ solution and a few tens of Å in pyrrole - H₂SO₄ solution. In H₂SO₄ solution, the very early stages of the electropolymerization lead to flat islands with a height of about 2.0 Å and a diameter of several tens of Ångstrom on Au(111) terraces, which indicates the dominance of two-dimensional polypyrrole structures. The surface population of these islands observed in sulphuric acid increases with the number, range, and decreasing potential scan rate of voltage cycles. At later stages and higher coverages the STM images show a further growth of overlapping PPy globules, which change from two- to three-dimensional structures. In aqueous Na₃AlF₆ solution, the STM images showed lifting of the Au(111) surface reconstruction, which may be due to the chemisorption of OH⁻. The early polypyrrole deposition in aqueous sodium hexafluoroaluminate, visible with nano-scale horizontal resolution, results predominantly in a 2D growth of the polymer globules having about 2.0 Å in height on the onset of the polymer deposition.

polypyrrole, Multicharged counter-anions, In-situ scanning tunneling microscopy, Cyclic voltammetry

http://dx.doi.org/10.1016/j.jelechem.2017.01.017

http://www.elsevier.com