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Exchanged Cations and Water during Reactions in Polypyrrole Macroions from Artificial Muscles
Author(s) -
Valero Laura,
Otero Toribio F.,
Martínez José G.
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201300878
Subject(s) - chemistry , electrolyte , aqueous solution , solvation , polypyrrole , redox , bilayer , ion , chloride , solvation shell , analytical chemistry (journal) , protonation , inorganic chemistry , electrochemistry , electrode , organic chemistry , membrane , biochemistry
Abstract The movement of the bilayer (polypyrrole–dodecylbenzenesulfonate/tape) during artificial muscle bending under flow of current square waves was studied in aqueous solutions of chloride salts. During current flow, polypyrrole redox reactions result in variations in the volumes of the films and macroscopic bending: swelling by reduction with expulsion of cations and shrinking by oxidation with the insertion of cations. The described angles follow a linear function, different in each of the studied salts, of the consumed charge: they are faradaic polymeric muscles. The linearity indicates that cations are the only exchanged ions in the studied potential range. By flow of the same specific charge in every electrolyte, different angles were described by the muscle. The charge and the angle allow the number and volume of both the exchanged cations and the water molecules (related to a reference) between the film to be determined, in addition to the electrolyte per unit of charge during the driving reaction. The attained apparent solvation numbers for the exchanged cations were: 0.8, 0.7, 0.6, 0.5, 0.5, 0.4, 0.25, and 0.0 for Na + , Mg 2+ , La 3+ , Li + , Ca 2+ , K + , Rb + , and Cs + , respectively.