Nucleation and Growth Mechanism of Electropolymerization of Methylene Blue: The Effect of Preparation Potential on Poly(methylene blue) Structure

Abstract

Nucleation and growth mechanism of electropolymerization of methylene blue (MB) in a basic medium and the effect of preparation potential on poly(MB) film structure were investigated by using cyclic voltammetry, potentiostatic current-time transient, scanning tunneling microscopy (STM), atomic force microscopy (AFM), and UV-vis. absorption spectroscopy techniques. Electropolymerization of MB has been achieved by potentiodynamic (cyclic voltammetry) and potentiostatic (constant potential) techniques. The potentiostatic current-time transients fitted with a theoretical model and morphological studies indicate that nucleation and growth mechanism of poly(MB) starts with a progressive layer-by-layer nucleation and growth besides random adsorption. Nucleation and growth of poly(MB) follows a process between progressive layer-by-layer and 3-D instantaneous mechanism resulting in highly-oriented poly(MB) nanofibers with increasing poly(MB) film thickness. Cyclic voltammetry and morphological studies exhibit that poly(MB) film structure changes depending on the preparation potential. Poly(MB) films prepared at the potential values of 900 and 950 mV show a well-ordered, smooth surface but at the potential values higher than 1000 mV, rough polymer surface arises as overoxidation takes place. UV-vis. absorption spectra of poly(MB) film and MB monomer show three peaks. The peak at 410 nm for poly(MB) shows 100 nm blue shift when compared to the MB monomer and is attributed to poly(MB) formation on the electrode.

Hybrid Organic Electrodes: The Rational Design and Synthesis of High-Energy Redox-Active Pendant Functionalized Polypyrroles for Electrochemical Energy Storage

“…34 However, the deposition of poly-3b, on the electrode surface, likely depends on the growth/generation of nucleation sites on the electrode surface since the electropolymerization process was less stable and involved multiply charged cation radicals of 3b. [35][36][37] During the polymerization process, as 3b gradually becomes more oxidized, the increasing repulsion between the electrode surface and +3 monomers could prevent all but a small fraction of the monomers from achieving the +3 state in the vicinity of the electrode surface. (Recall that that electropolymerization process takes place at applied potentials that are well positive of the point of zero charge for GCE, so the electrode surface is net positive).…”

Poly(methylene blue)-modified electrode for indirect electrochemical sensing of OH radicals and radical scavengers

“…Blank experiments were also performed. PMB films were dipped in aqueous solutions of iron (ii) The electropolymerization of the MB (Figure 1) reaches higher growth rates in basic solutions (Karyakin et al 1999, Kaplan et al 2010, Brett et al 1999, Marinho et al 2012, Liu and Mu 1999. Taking this into account, the electrochemical polymerization of MB for 30 cycles in pH 9.2 is shown in Figure 2.…”

“…The polymer film was used for a biomaterial due to its bioelectrochemical activity. The main advantage of electropolymerization of methylene blue (MB) relies on the long-term stability of the resulting polymer, which is synthesized from an inexpensive monomer in aqueous solution (Kaplan et al 2010). However, so far PMB was never used for sensing radicals and radical scavengers.…”

Surface‐Confined Electropolymerization of Methylene Blue on Gold Electrodes

“…Wang et al obtained a well-ordered monolayer of MB on Au(111) electrodes by electrodeposition from acidic MB solution, indicating that control of the electrochemical potential of the substrate allows controlling of moleculesubstrate interaction [27]. MB polymer thin films have also been prepared using neutral or basic MB monomer solution [7,[28][29][30][31][32][33][34][35][36][37]. However, the electropolymerization of SAMs of MB has not been studied until now.…”

“…We previously studied the nucleation and growth mechanism of electropolymerization of MB and the optimization of preparation potential to obtain a well-ordered structures of poly(MB) on gold substrates [37]. In this study, our aim is to obtain a highly-oriented ultra-thin films of poly(MB) by using surface-confined electropolymerization process with the contribution of the previous optimized conditions.…”