Template-based synthesis of nanotube and nanowire ferrofluids and their magnetoviscosity

在DFG优先计划SPP 1165“纳米线和纳米管”项目的这一拟议延续中，Nielsch小组将扩展原子层沉积（ALD）制备路线，以涵盖表现出超顺磁性行为的多层磁性纳米管。将遵循两种生长策略以获得超顺磁性状态-纳米层压材料的形成和三元氧化物的分解-Krill组将优化沉积后退火程序以定制所需的最终微观结构。此外，Nielsch小组将开发一种大规模生产铁磁纳米棒的新方法，该方法基于从单一浴中将磁性和磁性层交替电化学沉积到纳米多孔基质中。选择性地溶解基质和磁性间隔物片段将释放大量完整的铁磁纳米棒（每批高达1013-14），其纵横比可以通过调节磁性层厚度在0.3和20之间变化。Krill小组将测量纳米管、纳米线和混合（纳米管+纳米球）铁磁流体的磁粘滞性，并与乌尔姆的Kaiser小组一起，使用电子断层扫描和能量过滤透射电子显微镜阐明磁性成分的微观结构。

In this proposed continuation of a project from DFG Priority Program SPP 1165 “Nanowires and Nanotubes,” the Nielsch group will extend the atomic layer deposition (ALD) preparation route to encompass multilayered magnetic nanotubes manifesting superparamagnetic behavior. Two growth strategies will be followed to obtain the superparamagnetic state - formation of nanolaminates and decomposition of a ternary oxide - and the Krill group will optimize post-deposition annealing procedures to tailor the desired final microstructure. In addition, a new approach to the mass production of ferromagnetic nanorods will be developed by the Nielsch group based on alternating electrochemical deposition of magnetic and nonmagnetic layers into a nanoporous matrix from a single bath. Selective dissolution of the matrix and the nonmagnetic spacer segments will release huge quantities of intact ferromagnetic nanorods (up to 1013-14 per batch), the aspect ratio of which can be varied between 0.3 and 20 by adjusting the magnetic layer thickness. The Krill group will measure the magnetoviscosity of nanotube, nanowire and hybrid (nanotube+nanosphere) ferrofluids, and, together with the Kaiser group in Ulm, elucidate the microstructure of the magnetic constituents using electron tomography and energy-filtered transmission electron microscopy.