A Fundamental Study of Charge Effects on Melt Electrowritten Polymer Fibers
A Fundamental Study of Charge Effects on Melt Electrowritten Polymer Fibers
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DOI：
10.1016/j.matdes.2019.107857
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发表时间：
2019-09-15
影响因子：
8.4
通讯作者：
Chang, Robert C.
中科院分区：
文献类型：
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作者：
Ding, Houzhu;Cao, Kai;Chang, Robert C.
熔体电写(MEW)是一种基于电流体动力学(EHD)的添加剂制造范例，用于印刷微米级纤维。虽然已经描述了EHD打印过程中的电荷传输模型，但MEW过程中的过程中电荷动态出现了重大挑战，这限制了可实现的打印分辨率。本文提出了一种分析电荷动力学对微印结构分辨率影响的方法。首先，用振荡刀具路径印刷的纤维显示出两种不同的对准图案，组成纤维要么沿着刀具路径连续重叠，要么分叉成单独的纤维，分别在导电和非导电衬底上没有明显重叠，这表明存在纤维间电荷现象。接下来，在两种类型的衬底上印刷一组直纤维，以研究规定的纤维间距(设定S-f)与测量的S-f之间的关系。排斥力(测量S-f和gt；集合S-f)和吸引力(测量S-f和lt；集合S-f)都被观察到。此外，还提出了基于线-点电荷相互作用的数学模型来解释纤维的吸引-排斥现象。最后，用定制的法拉第杯进行的剩余电荷测量表明，导电和非导电衬底上的印刷支架分别为剩余电荷带负电荷和正电荷。(C)2019年提交人。爱思唯尔有限公司出版。
Melt electrowriting (MEW) is an electrohydrodynamics (EHD)-based additive manufacturing paradigm for printing microscale fibers. Although models for charge transport during EHD printing have been described, significant challenges arise from the in-process charge dynamics in MEW process, which limits the achievable print resolution. This paper advances a methodology to analyze the effects of charge dynamics on the MEW-printed structure resolution. First, fibers printed with an oscillating toolpath exhibit two distinct alignment patterns with constituent fibers either successively overlapping along the toolpath or diverging into individual fibers without apparent overlap on conductive and non-conductive substrates, respectively, pointing to the existence of inter-fiber charge phenomena. Next, a set of straight fibers are printed on two types of substrates to investigate the relationship between the prescribed inter-fiber distance (set S-f) and measured S-f. Both repulsion (measured S-f > set S-f) and attraction (measured S-f < set S-f) are observed. Moreover, a mathematical model based on line-point charge interactions is advanced to explain the fiber attraction-repulsion phenomenon. Finally, residual charge measurements with a customized Faraday Cup reveal that printed scaffolds on conductive and non-conductive substrates are negatively and positively charged for residual charge, respectively. (C) 2019 The Authors. Published by Elsevier Ltd.