Actuation mechanism of solid state polypyrrole actuator according to dopant size.

To investigate the effect of dopant size, especially that of anion size, on the actuation behaviour of polypyrrole (PPy) actuator, the authors prepared PPy actuators with three types of dopants: sodium perchlorate (NaClO₄ with small anion), para-toluene sulfonate (pTS with medium anion) and dodecyl benzene sulfonate (DBS with bulky anion). The largest displacements of 12·95, 8·36 and 9·62 mm were obtained in PPy actuators with NaClO₄, pTS and DBS respectively. This result was caused by the cation and anion size of dopant used in this study. [ABSTRACT FROM AUTHOR]