Morphological characterization and analytical application of poly(3,4-ethylenedioxythiophene)–Prussian blue composite films electrodeposited in situ on platinum electrode chips

Electrochemical in situ preparation and morphological characterization of inorganic redox material-organic conducting polymer coatings as thin films on platinum electrodes are presented. Composite inorganic–organic coatings consist of Prussian blue (PB) and [poly(3,4-ethylenedioxythiophene)] (PEDOT), and PEDOT organic polymers doped with ferricyanide (PEDOT–FeCN). The PEDOT coating deposited from an aqueous solution containing the 3,4-ethylenedioxythiophene monomer and LiClO4 as supporting electrolyte was used as a “reference” material (PEDOT–ClO4). The composite coatings were prepared by electrochemical methods on platinum electrode chips, which consist of a 150 nm Pt layer deposited on 100-oriented standard 3″ silicon wafers. Electrochemical behavior of the composite inorganic–organic coatings is based mainly on inorganic component redox reactions. Different surface properties of the composite materials were studied. Thus, the roughness of the deposited films was measured by both atomic force microscopy (AFM) and profilometry, leading to roughness values ranging from 3 nm to 217 nm for PEDOT–ClO4, and PEDOT–FeCN and PEDOT–PB coatings, respectively. AFM and Scanning Electron Microscopy pictures were also produced to characterize the film morphologies, and revealed a granular pattern of the deposited inorganic component inside the organic polymer matrix. Moreover, the adhesion properties of the composites were studied by AFM and proved to be very different from one material to the other depending on the film structure. The electrochemical responses of these composite coatings to H2O2 reduction were also investigated using chronoamperometry. A linear response over a concentration range from 1 × 10− 4 to 1 × 10− 5 M and a detection limit of 10 μM were obtained.