AFM and SEM Characterization of Chemically Modified Electrodes Based on 5-[(azulen-1-yl) methylene]-2-thioxothiazolidin-4-one

Abstract

Preparation and microscopy characterization of polymer modified glassy carbon electrodes based on (5-[(azulen-1-yl) methylene]-2-thioxothiazolidin-4-one (L) were reported. Atomic Force Microscopy was used to investigate the morphological and mechanical properties of the deposited polyL films onto glassy carbon. The topography images of the analyzed samples exhibited the presence of some columnar shape features onto the layer surfaces. The surface roughness of the layers deposited at constant charge calculated from topography images, increased with the more positive applied potential for controlled potential electrolysis. At different charges, the roughness parameter showed the same behavior for the layers obtained applying a constant potential without having a noticeable influence on the adhesion properties on the substrate. Analysis using scanning electron microscopy shows a relatively uniform surface arrangement of the polymer and the presence of some clusters which are disturbing the planarity. PolyL chemically modified electrodes have been used for heavy metal ions detection with best results for lead.

Surface Characterization of New Azulene-Based CMEs for Sensing

“…The electrochemical experiments were performed using PGSTAT 12 AUTOLAB potentiostat (Utrecht, The Netherlands) connected to a three-electrode cell [19][20][21][22][23]. Bare or modified glassy carbon (GC) disks (3 mm diameter, Metrohm, Herisau, Switzerland) were used as working electrodes.…”

“…CMEs were tested for electrochemical detection of HMs ions in 0.1 M buffer acetate (pH 5.5) solution as supporting electrolyte, following the procedure detailed in [19][20][21][22][23].…”

“…The binding of thiadiazole to an azulene residue is an unexploited subject in the literature and creates the premise for recognition of HMs using CMEs based on T. The electropolymerization of similar azulenes [20] can occur by π-steaking [21]. Only few surface studies related to azulene-based CMEs are reported [22,23]. SEM investigation of polymerized polyazulene films can be found in the literature for polyazulene films used as supercapacitors [24], ion-to-electron transducer materials in solid-contact ion-selective electrodes [25], copolymers based on azulene and 3-thiophene acetic acid [26].…”

Polyazulene-Based Materials for Heavy Metal Ion Detection. 3. (E)-5-((6-t-Butyl-4,8-dimethylazulen-1-yl) diazenyl)-1H-tetrazole-Based Modified Electrodes

“…SEM measurements were performed at different magnifications on L-CMEs prepared at different potentials and at the same polymerization charge [13,16]. The influence of the potential on the morphology of the films prepared at three significant potentials (+0.5, +0.8 and +1.3 V) is presented in Figure 7.…”

“…Previous studies performed in our team have highlighted the possibility of using azulene derivatives to obtain modified electrodes for HM dosing [13]. The complexing units were based on pyridine [14], tetrazoles [13,15], thiadiazoles [16], etc. Among the most recent results [13], there are tetrazoles that have quite low detection limits (less than 5 × 10 −8 mM).…”