纳米技术和纳米材料近年来获得了飞速发展，他们将在航空航天、医学、功能材料、电子等领域获得广泛的作用。电纺丝技术是一种制造连续纳米或亚微米纤维的简便和廉价的技术，被认为是制造连续、任意长纳米纤维的唯一理想的方法。因此，电纺丝技术引起了越来越多的关注。本文主要介绍了在制造任意长、单方向排列纳米纤维上的研究成果。使用正、负喷头对喷的新方法，有效解决了不能在大面积上连续收集高度有序排列纳米纤维的问题。 建立了电喷雾和电纺丝实验平台，研究了电喷雾的喷射模式和稳定的锥-射流模式的获得和控制，在此基础上实现了电纺丝的稳定锥-射流模式喷射，并获得了连续的、直径均匀的聚乙烯醇（PVA）纳米纤维。此外，还讨论了电压、喷射距离、聚合物溶液浓度等参数对电纺纳米纤维的影响。 设计了新的喷射装置，使用两个分别接正、负电的喷头正对放置来进行喷射，喷出的带不同电荷的纤维在空中吸引、碰撞，成为整体呈电中性的稳定纤维束，然后被高速旋转的圆筒收集。使用这种方法实现了有序纳米纤维的连续收集。使用不同材料的聚合物溶液，研究了收集速度对收集效果的影响。提出极限收集速度的概念，并研究了影响极限收集速度的因素。证明了对于浓度合适的聚乙烯醇和聚乙烯吡咯烷酮（PVP）溶液，可以在极限收集速度下收集到高度有序排列的纳米纤维。此外，还研究了影响收集过程的其它参数。 分析了对喷电纺法的收集机理，指出正、负喷头同时喷射产生的“电中和”效果以及收集系统不再作为电极使用，是这种方法相比于传统方法的进步之处，并保证了有序纳米纤维的长时间稳定收集。 设计实验来拓展对喷电纺法的应用，证明了这种方法可以被改造来制造聚合物纳米纤维线，多方向有序排列的层级纳米纤维结构以及聚合物纳米纤维和纳米颗粒的复合结构等。
Nanotechnology and nanomaterial have a very rapid development recent years, and they will be used for many applications, such as spacecraft, medicine, functional material, electronic and optical devices etc. Electrospinning is a very simple and inexpensive technique to manufacture sub-micro and nanofiber, it also considered as the only one method which can be developed for mass production of one-by-one continuous nanofibers from various polymers. Therefore, electrospinning attracts more and more interest. The results of manufacture infinite length, well-aligned polymer nanofibers are introduced in this thesis. A new two-needle electrospinning design is developed to produce continuous well-aligned polymer nanofibers over a large area.An experiment system is established to study the mechanism of electrospray and electrospinning. The spray modes are investigated to comprehend the establishment and control of the stable spray in cone-jet mode. The as-spun system is controlled to be working on stable, cone-jet mode, and continuous PVA nanofibers with a uniform diameter are produced. The influence of parameters, including work voltage, distance between the needle and collector etc, on the manufacture of nanofibers is discussed. A new electrospinning system is designed, two oppositely placed needles are used, and they are connected to positive and negative voltages, respectively. The spun fibers with opposite charges attract each other, stick together and form a yarn, which is neutral as a whole. The stable yarn can be wound on a rapidly rotating collector. Aligned nanofibers are continuously collected using this technique.Different polymer solutions are used to study the influence of colleting velocity on the fibers alignment. A maximal take-up velocity is found, and the parameters influence it is investigated. It is proven that for PVA solution and PVP solution with a suitable concentration, nanofibers collected on the maximal take-up velocity have very well alignment. The process parameters are also studied.An analysis of the mechanism of the fibers alignment is given, and it indicate that the mass production of well-aligned polymer nanofibers for a long time attribute to the electrical neutralization of the two-needle electrospining system and the separation of the collector from the electrical system.Experiments are designed to extend the two-needle electrospinning system for other applications. It is proven that this technique can be developed to manufacture well-aligned nanofibers yarn, layer-by-layer stacked films making up of well-aligned nanofibers, and composite of polymer nanofibers and nanoparticles.
