这篇论文主要是利用力控电纺丝方法的近场特点，纤维沉积到基板上时依然是液体，利用基板运动速度产生的纤维拉力和沉积在基板表面张力之间的竞争关系，实现点大小、间距的可控直写。并通过实验得到电纺丝直写的3个不同阶段。 力控电纺丝的基本思想是通过宏观的运动来控制微纳米纤维的定位和形貌，能够极大地提高电纺丝直写的可控性，并且由于机械拉力的存在，可以有效地降低电压，这有利于在聚合物上直接沉积结构，避免了被击穿。 Tunable bead-on-string microstructures fabricated by mechano-electrospinning, JOURNAL OF PHYSICS D: APPLIED PHYSICS，2012 论文地址： http://iopscience.iop.org/0022-3727/45/40/405301 直接下载： JAPD-出版.pdf 【摘要】This paper presents mechano-electrospinning process to fabricate bead-on-string microstructures in a continuously tunable manner. The thin jet is pulled onto the substrate by the stable electric field force and tunable mechanical drawing force, then bead-on-string structures are generated by means of the force exerted on the jet at the contact point in the horizontal direction changes from capillary force, resisted viscosity force to friction force. When the mechanical drawing force in horizontal direction overtakes the surface tension, bead-on-string structures become continuous line structures by adjusting the substrate velocity. In stable formation process of the bead-on-string, one period can be divided into three stages from the point of view of jet behaviors: being anchored, being stretched, and skipping. The bead-size and the bead-gap are all continuously tunable through mechano-electrospinning process. The fabrication mechanisms of bead-on-string microstructure are uncovered through theoretical analysis and experimental characterization. When the critical velocity achieves, the combination of drawing force and electric field force leads the bead-on-string microstructures to continuous lines. It is a flexible and high-controllable method to fabricate bead-on-string microstructures.
这种点阵制备方法是非常偶然情况下发现的，原来只是利用机-电纺丝工艺直写纤维网格，然后就将直写的纤维网格放到显微镜下观测，由于不小心呼吸时的水汽凝结在纤维网格所沉积的Si衬底上，然后纤维就形成了比较规则的点阵列。后来才有了这篇论文的工作。所以实验过程中遇到的失败或者偶尔现象往往都是非常值得研究的课题。 论文：Controllable self-organization of colloid microarrays based on finite length effects of electrospun ribbons,Soft Matter, 2012,8, 8302-8311 论文地址： http://pubs.rsc.org/en/Content/ArticleLanding/2012/SM/c2sm25535a 。 直接下载： SoftMatter出版.pdf 这部分工作主要是利用机-电纺丝工艺直写出特定的纤维网格，由于网格交点具有锚固作用，可以控制每一段纤维的长度，通过表面张力和Plateau–Rayleigh 不稳定性实现点阵的自组装。本方法可以控制点阵的密度、点的大小、点的间距等。实验结果与已有的理论值吻合的非常好。本方式适合于大规模的点阵制备。 摘要：This paper presents a mechanoelectrospinning (MES)-assisted surface-tension driven self-organization to provide a possible route towards inexpensive generation of large-scale ordered microarrays in a controllable manner. To control the self-organization driven by surface tension and Plateau–Rayleigh instability, finite length effects are utilized to manipulate the self-organizing processes and adjust the competition between nucleation and free surface instability. We introduce fine ribbon-lattices to determine the boundary conditions of ribbons to make use of the finite length effects. The ribbon-lattices are electrodeposited precisely by MES, borrowing ideas from the “Chinese kite”, by involving the mechanical drawing force and the electric field force. Then the samples are transferred to a moisture-rich environment in which the ribbons absorb water vapour and become liquid lines. Surface instability emerges and leads the liquid lines to controllable self-organization. We uncover the controllable area to manipulate the self-organization behavior. A uniform or hierarchical microarray with a specific position, gap and droplet-size can be generated in a continuously tunable manner. This bottom-up method provides a digital approach for the fabrication of large-scale ordered microarrays and micropatterns. （1）下图是本工艺的原理图——先止血纤维阵列，再移到湿润环境，然后进行自组装，最后进行干燥，形成点阵。 （2）下图是工艺参数对点阵大小的控制规律 （3）下图是线段长度与点间距的关系。
好久没有来此发博文了，主要是不知道能写什么，一直好像是嘴尖皮厚腹中空。不过觉得科学网这个交流平台非常不错，时不时的有些朋友通过这里能够联系到我，我也想着以后能够慢慢的逐渐将我的自留地都种上蔬菜和水果。 后面慢慢与大家分享一些自己一些研究结果，与大家一起讨论，也希望大家能够多给一些建议。 论文：Continuously tunable and oriented nanofiber direct-written by mechano-electrospinning 是在近场电纺丝基础上改进的一种方法，突出平台运动对电纺纤维的控制。利用运动平台的运动控制纤维直线度、直径，通过电极间距控制沉积“纤维”的形貌，如纤维和丝带。这样就可以利用平台的运动实现微结构的直写。这种电纺丝工艺注重的是运动平台对纤维的可控性，类似于风筝，通过类似于人的跑位和运动速度实现纤维定位和作用力的控制。 摘要：A mechano-electrospinning method is presented to direct-write oriented nanofiber with high deposition accuracy in continuously tunable manner. This method is able to use a large nozzle to deposit high-resolution fiber-arrays by near-field localization. Due to the existence of mechanical drawing force, a higher resolution pattern can be direct-written by a lower voltage, which just keeps the Taylor cone stable. Then the fiber is stretched through a moving substrate, by which the deposited fiber can be continuously tuned from 400 nm to 200 nm in a linear relationship. The effects of the speed on the diameter and morphology of fibers are studied, and the analysis of the mechanism of the fiber alignment is given. The positionability and controllability make mechano-electrospinning much different from the traditional electrospinning, which only collects the fibers in the form of nonwoven fabric. In addition, the fibers fabricated by this method can directly deposit over a large flat area in the form of arrays and complex patterns with high precision. 下图是运动平台不同速度下的对纤维的拉伸作用，类似于中国的风筝。 下图是通过基板速度和电极间距控制纤维的直径和形貌
本课题组从改善静电纺丝过程中点－面非均匀电场分布的角度出发，设计了二维金属针尖阵列收集装置，分别得到了垂直交叉阵列纳米纤维和定向排列纳米纤维图案。 C. Pan, Y.-H. Han, L. Dong, et al., J. Macromol. Sci., Part B: Phys. 2008, 47, 735-742.
标签: 静电纺丝
