Lee Alexander S, Peteu Serban F, Ly James V, Requicha Aristides A G, Thompson Mark E, Zhou Chongwu
Laboratory for Molecular Robotics, University of Southern California, Los Angeles, CA 90089, USA. Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA.
Nanotechnology. 2008 Apr 23;19(16):165501. doi: 10.1088/0957-4484/19/16/165501. Epub 2008 Mar 18.
Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.
纳米级致动器是未来纳米机电系统（NEMS）和纳米机器人的关键组件，有望成为纳米技术领域的一个主要发展方向。本文首次证明，直径小于100纳米的单个聚吡咯（PPy）纳米线具有致动行为，因此有可能用于构建纳米级致动器。聚吡咯是一种电活性聚合物，可根据其氧化态改变体积。基于聚吡咯的宏观和微观致动器已得到证实，但纳米级的同类产品至今尚未实现。本文所报道的研究对聚吡咯纳米线在纳米尺度下是否仍表现出有用的体积变化这一基本问题给出了肯定回答。通过使用径迹蚀刻聚碳酸酯膜作为模板进行化学聚合，制备出了直径为50纳米、长度约为6微米的纳米线。利用电化学原子力显微镜（AFM）研究了它们作为氧化态函数的致动响应。基于AFM悬臂的位移，对最小致动力进行了估算。
