Hydrogen bubble‐assisted syntheses of polypyrrole micro/nanostructures using electrochemistry: structural and physical property characterization

Abstract

Polypyrrole (PPy) in the family of p-conjugated polymers is a potential candidate for microscopic actuators, electrochromic devices, batteries, and drug delivery systems. We report the controlled syntheses of PPy micro/nanocontainers through electrochemical generation of H 2 bubbles from a surfactant cum electrolyte b-NSA (b-naphthalene sulfonic acid) stabilized on the working electrode, followed by electrochemical polymerization of monomer (pyrrole) around the wall of the micelles serving as template. It is noticed that the density, shape, caliber, and thickness of self-assembled PPy micro/nanocontainers can be regulated by electrochemical potential window for H 2 bubbles and number of cyclic voltammetric scans for the electropolymerization of pyrrole. Sodium chlorate and perchlorate are used to synthesize conventional PPy films. By changing the dopant structure, one can control the microscopic structure and physical properties, which are analyzed using multiple microscopic techniques and X-ray diffraction (XRD), infrared, vis Raman and X-ray photoelectron spectroscopic analytical tools. In light of this information, an exhaustive description of the material is attained. Experimental results show that the films consist of spherical/globular surface morphology and cup-/bowl-like structures, which becomes lantern-like with increasing cyclic voltammetry scans. The bowl diameter and caliber and room temperature conductivities range 0.05-60 µm, 5-50 µm and 2 × 10 −2 -20 S cm −1 , respectively. Raman spectroscopy (RS) helps to identify the oxidized PPy; polaron and bipolaron states and thus a detailed molecular structure. The results also showed that the relative conjugation length increases with decreasing size of the morphological feature. Moreover, these studies enhanced the understanding of bubble nucleation at the solid-electrolyte interface.

Synthesis and characterization of polypyrrole doped with anionic spherical polyelectrolyte brushes

“…The peak at 1578 cm -1 (1581 cm -1 for PPy) attributable to C=C stretching is considered to be an overlap of two oxidized structures. Therefore, compared with the PPy, PPy/ASPB nanocomposite has an increased portion of bipolarons (1255 cm -1 ) relative to polarons in the Raman spectrum, leading to the high conductivity [27].…”

Effects of Pyrrole Polymerizing Oxidant on the Properties of Pyrolysed Carbon-Supported Cobalt-Polypyrrole as Electrocatalysts for Oxygen Reduction Reaction

“…4 shows the Raman spectra of the Co-PPy-TsOH/C catalysts prepared from diverse pyrrole polymerizing oxidants along with that of BP2000 carbon powder, PPy and PPy-TsOH/C from APS, PPy-TsOH/C-APS+Co(Ac) 2 (PPy-TsOH/C-APS impregnated cobalt ion on the surface) for comparison. As in the previous work, 15 the characteristic peaks generally observed in the wavenumber rang from about 900 to 1150 cm −1 for PPy and 1370 cm −1 for antisymmetric in-ring C-N stretching 18,19 disappeared in all the Co-PPy-TsOH/C catalysts, while only two peaks representing the disorder-induced band (D band) and the graphite band (G band) for carbon can be found, indicating that the structure of PPy has been destroyed by decomposition and the nitrogen in PPy has inserted into the carbon layers during the high temperature pyrolysis. Fig.…”

Facile template-free electrochemical preparation of poly[N-(2-cyanoethyl)pyrrole] nanowires

“…Furthermore, while PPy exhibits bands due to the bipolaron and polaron species at 940 and 980 cm -1 respectively, only the latter is distinguishable in the PPyEtCN spectrum. The ratio of the intensity of the ν(C = C) band to that of the skeletal band at 1503 cm -1 gives a measurement of the relative amounts of conjugation in the two polymers [21]. The ratios were determined to be approximately 2.7 and 2 for the PPy and PPyEtCN systems respectively, indicating the lower degree of conjugation in the PPyEtCN film.…”