Electrodeposition of Polypyrrole/Carboxymethyl Cellulose on Platinum and Indium Tin Oxide

Abstract

ABSTRACT:The paper presents information on the synthesis and properties of a composite material consisting of an electronically conducting polymer and a polyanion. This kind of materials are of current interest. Polypyrrole-carboxymethyl cellulose composite have been studied on two different substrates: platinum and indium tin oxide. Electrochemical, SEM, and U.V-visible techniques have been used. The mechanism in both electrodes seem to be the same, but the morphology was quite different with the same electrodeposition conditions. Dendritycal growth on indium tin oxide in special conditions has been observed.KEY WORDS Polypyrrole I Electropolymerization I Carboxymethylcellulose I Polymer Morphology I Conductivity IIn the last few years conducting polymers, particularly in the form of thin films on electrodes surfaces have received considerable attention. A number of publications have demonstrated the possibilities of using these polymer films. Some examples are: as electrochemical sensors/ -3 electronic devices, 4 • 5 rechargeable batteries, 6 photoelectrochemical cells 7 and controlled drug release.8·9Several studies have reported on the early stages of deposition of polypyrrole films onto metal, indium oxide or vitreous carbon electrodes. 10 -12 In all cases, the cyclic voltammograms show nucleation loops, such a behavior is good evidence that the formation of a conducting polymer layer occurs by a mechanism involving nucleation of centres of the new phase followed by a three dimensional growth.This kind of mechanism has been proposed when polypyrrole was electrodeposited from a solution containing small anions such as Cl04 . 13 This and other polymers can be obtained when multy-charged anions called polyanions are used. The interaction between the positively charged polyheterocycle and the charge compensating polyanion forces intimate mixing of the two polymers. The mechanism in the last case has been less studied.On the other hand, the degree of molecular ordering of a conductive polymer is determined by a combination of different factors. Among these are: The steric/ electronic nature of the monomer unit and the method and conditions of polymer preparation. Another very important factor is the nature of the incorporated dopant anion. For example, significant morphological differences should exist in a given or polyanion as opposed to a small inorganic dopant.The most important purpose of this work is to assess the role of carboximethyl cellulose in morphology. Different papers in the thermoplastic field have been published with wood cellulose, these first works showed problems with the hidrophilic incompatibilities of absorption of water in the cellulose fiber and hydrophobic of the thermoplastic matrix. These results gave composites with poor technological properties. In the last few years new perspectives in this field have emerged using biodegradable composites. In this way the chemical and electrochemical production of composites such as polypyrrole/carboximethyl cellulose could yield a chemically mod...

Electrochemical Capacitance of Nanocomposite Polypyrrole/Cellulose Films

“…An oxidation loop was observed in each case, which is common during electropolymerization of ECPs. 42,43 The presence of the oxidation loop indicates growth of the polymer on the electrode surface by a nucleation and growth mechanism, 37,42 in which ECP deposition on the reverse sweep occurred preferentially on the preexisting polymer surface. 43 CVs recorded in 0.5 M PY in a 0.29 wt % aqueous CNXL suspension (Figure 1B) were very similar to those obtained in KCl.…”

“…36 Molecular carboxymethyl cellulose has also been co-electrodeposited into PPY nanocomposites. 37 The major advantage of CNXLs is that, using simple chemistry, a high density of negative charge can easily be introduced to the CNXL surface. We anticipate that this may allow us to incorporate the CNXLs into the ECP structure as the counteranions during electrodeposition, as has been achieved previously using CNTs.…”

Recent Advances in the Application of Natural Fiber Based Composites

“…This showed photoelectric behavior, where the conductivity of the polymer increased when supported with cellulose membrane, although the complete mechanism of this behavior was not entirely understood. [73,74] To demonstrate the applicability of cellulose as a smart electro-active material, a bending actuator was processed, fabricated and tested using cellulose paper by Kim et al [75] The concept of electroactive papers is demonstrated in Figure 3, which shows the cellulose electroactive paper as a bending actuator. Gold electrodes were deposited on both sides of the cellophane by means of physical vapor deposition.…”

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“…Few research efforts on carboxymethylcellulose (CMC), a bio-degradable polymer, have been reported as the insulating polymer for preparing polypyrrolecarboxymethylcellulose (PPY-CMC) composite film [12][13] . All these attempts have been focused on the cyclic voltammetry and morphological studies of PPY-CMC composite film [12][13] only, but no research reports are available on their conductivity or mechanical properties.…”

“…All these attempts have been focused on the cyclic voltammetry and morphological studies of PPY-CMC composite film [12][13] only, but no research reports are available on their conductivity or mechanical properties.…”