Reversible electrochemical reactions in conducting polymers: A molecular approach to artificial muscles
✍ Scribed by T. F. Otero; H. Grande; J. Rodríguez
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 455 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0894-3230
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✦ Synopsis
Electrical currents trigger oxidation or reduction reactions in conducting polymers. Changes in volume associated with these redox processes can be transformed into macroscopic movements of more than 180" by the construction of a bilayer: polypyrrole-flexible and inactive polymer (artificial muscle). The effects of the applied potential, the nature of the solvent and the electrolyte concentration on the angular movement of the free end of the bilayer were analysed. The movement accelerates with increasing anodic (or cathodic, when the movement is reversed) overpotentials, with increasing electrolyte concentration or by using more polar solvents, leading to the conclusion that the movement is linked to electrochemically driven exchange of hydrated counterions between the solution and the conducting polymer. Geometrical considerations give a simple equation for both the microscopic and macroscopic changes of volume associated to the penetration of counterions during oxidation, which is able to explain the experimental behaviour.