Magnetoviscosity of nanorod ferrofluids synthesized by virus templating

本论文拟进行一项为期两年的研究计划，通过病毒模板辅助合成铁磁性纳米线和纳米管，制备新型纳米棒铁磁流体。如果我们目前对磁流体中磁场诱导的粘度增强的理解是正确的，那么棒状铁磁纳米颗粒应该能够显著提高稳定性，以对抗困扰传统磁流体的剪切变稀，这表明纳米棒磁流体将非常适合用于自适应阻尼系统或任何其他受益于通过液体传递力的应用。本项目的主要目标是（1）从植物或酵母培养物中制备大量高度稳定、无致病性的烟草花叶病毒（TMV）;（2）将TMV作为生物模板用于生长具有可控纵横比的铁磁纳米线和纳米管;（3）将纳米棒悬浮在合适的载体流体中并表征所得铁磁流体的磁特性;（4）将铁磁纳米线和纳米管悬浮在合适的载体流体中并表征所得铁磁流体的磁性。（4）测量纳米棒铁磁流体的频率依赖性复数粘度，并将其与常规铁磁流体的频率依赖性复数粘度进行比较;以及（5）测试作为悬浮铁磁颗粒的纵横比的函数的粘度增强的理论模型的预测。

A two-year research project is proposed to prepare novel nanorod ferrofluids by virustemplate- assisted synthesis of ferromagnetic nanowires and nanotubes. If our current understanding of the magnetic-field-induced viscosity enhancement in ferrofluids is correct, then rod-shaped ferromagnetic nanoparticles should impart a dramatically improved stability against the shear thinning that plagues conventional ferrofluids, suggesting that nanorod ferrofluids would be ideal for usage in adaptive damping systems or in any other application benefiting from force transfer via liquids. The primary goals of this project are (1) to prepare large amounts of the highly stable, non-pathogenic tobacco mosaic virus (TMV) from plants or yeast cultures; (2) to employ TMV as a biotemplate for the growth of ferromagnetic nanowires and nanotubes of controlled aspect ratio; (3) to suspend the nanorods in a suitable carrier fluid and characterize the magnetic properties of the resulting ferrofluid; (4) to measure the frequency-dependent complex viscosity of nanorod ferrofluids and compare it to that of conventional ferrofluids; and (5) to test the predictions of theoretical models for the viscosity enhancement as a function of the aspect ratio of suspended ferromagnetic particles.