Asymmetric Bilayer Artificial Muscles Based on Polypyrrole

The characteristics of the asymmetric artificial muscles, PPy-ClO4/tape, PPy-DBS/tape and PPy-ClO4/PPy-DBS worked in 0.5 M NaClO4 aqueous solutions were discussed by the dynamo-voltammetric responses, coulo-dynamic Evolution responses and the bending angle per unit of consumed charge and the cooperative dynamic effects of PPy-ClO4/PPy-DBS artificial muscles is clarified. In the PPy-ClO4/PPy-DBS asymmetric bilayer artificial muscles, the PPy-ClO4 layer shrinks and PPy-DBS layer swells during reduction and the PPy-ClO4 layer swells and PPy-DBS layer shrinks during oxidation. The artificial muscle originates cooperative dynamic bending actuation of the constituent layers (swelling/shrinking or shrinking/swelling) and achieves the larger bending amplitude than those of the PPy-ClO4/tape and the PPy-DBS/tape. The bending angle per unit of consumed charge on the PPy-ClO4/tape and PPy-DBS/tape is 3.240 and 2.85, respectively, and the cooperative dynamic effect on PPy-ClO4/PPy-DBS is 8.257. In case of NaCl having same level bending angle per unit of consumed charge on PPy-DBS/tape, 2.396, the cooperative dynamic effect on PPy-ClO4/PPy-DBS is just 3.868. Because the bending angle per unit of consumed charge on PPy-ClO4/tape is very low, 0.101. Actually, the cooperative dynamic effect on PPy-ClO4/PPy-DBS in Na2CO3 is 5.184 and is larger than that in NaCl even the bending angle per unit of consumed charge on PPy-DBS is lower than that on NaCl. The expansion and contraction of the PPy-ClO4 film dominates the reaction-driven bending motion and those of the PPy-DBS have a minor influence on the bending actuation.