Modified Equation for Predicting the Radius of Assembled Superstructures Made of Nanowires Including Polypyrrole Segment of All Length Scales

Gold-polypyrrole segment nanowires prepared using anodized aluminum oxide templates can be assembled into a curved superstructure that shows stimuli-induced contraction and expansion. The radius of the superstructures can be predicted using the simple equation suggested by J. K. Lim et al. (Nano Lett. 8, 4441 (2008)). The suggested equation, however, is valid only within the limiting condition in that the length of the polypyrrole segment is comparable to, or much longer than the gold segment. In this study, the original equation was modified to a new equation that is valid for all length scales of polypyrrole segments. The radius of the superstructures calculated using the modified equation was compared with the result calculated by the original equation, and the validity of the modified equation is discussed.