Shear moduli of anion and cation exchanging polypyrrole films

Electrochemical and viscoelastic evolution of dodecyl sulfate-doped polypyrrole films during electrochemical cycling

“…The viscoelastic properties of CPEs have been extensively investigated through the electroacoustic impedance method [31][32][33], by which the storage (G´) and loss moduli (G") of the polymer film can be determined. As the film ages, the viscoelastic changes may occur inside the film due to polymer chain rearrangements and species transfer through film/electrolyte interface [32].…”

Ion and solvent transfers accompanying redox switching of polypyrrole films immersed in divalent anion solutions

“…Films doped with different sulfonate anions under cyclic voltammetric conditions were characterized by means of XRD and AFM [24] and found to have different redox activity. Acoustic impedance was used to determine mechanical properties (in the form of storage and loss shear moduli, G and G ) for PPy films grown from lithium perchlorate and sodium ptoluenesulfonate solutions; oxidized (doped) films were stiffer [31]. Recently, the temperature dependence of the complex shear modulus of PPy exposed to different electrolytes was determined over the range 15-50 • C: both G and G decrease for anion-exchanging films but both are constant for cation exchanging films [32].…”

Temperature dependence of the complex shear modulus of cation and anion exchanging poly(pyrrole) films

“…All this should introduce additional stress in the film. Indeed, we have demonstrated that such films have very large shear moduli, up to 10 9 -10 10 dyn/cm 2 upon deposition [2]. Subsequent cycling leads to a decrease by 1-2 orders of magnitude to values of 10 8 dyn/cm 2 if the film remains a cation exchanger.…”

“…It was shown that mechanical elastic shear moduli G 0 and G 00 for such films are relatively small, ca. 10 6 dyn/cm 2 [2]. When polymerised in the presence of large surfactant anions, particularly aromatic, such as tosylate (Tos), dodecylbenzenesulfonate (DBS), poly(styrenesulfonate) (PSS), PPy becomes a cation exchanger.…”

“…So far, among the studied polymers were: poly(3-methylthiophene) [6], regioregular poly(3-hexylthiophene) [7,8] and poly(3-decylthiophene) [9], poly(3,4-ethylenedioxy thiophene) [10,11], poly(pyrrole) [2], and poly(vinylferrocene) [12] and self-assembled polyelectrolytes [3,4,13,14]. In a typical experiment, the polymer is deposited on a thin (ca.…”