Melt electrowriting (MEW) is an aspiring 3D printing technology with an unprecedented resolution among fiber-based printing technologies. It offers the ability to direct-write predefined designs utilizing a jet of molten polymer to fabricate constructs composed of fibers with diameters of only a few micrometers. These dimensions enable unique construct properties. Poly(ɛ-caprolactone) (PCL), a semicrystalline polymer mainly used for biomedical and life science applications, is the most prominent material for MEW and exhibits excellent printing properties. Despite the wealth of melt electrowritten constructs that have been fabricated by MEW, a detailed investigation, especially regarding fiber analysis on a macro- and microlevel is still lacking. Hence, this study systematically examines the influence of process parameters such as spinneret diameter, feeding pressure, and collector velocity on the diameter and particularly the topography of PCL fibers and sheds light on how these parameters affect the mechanical properties and crystallinity. A correlation between the mechanical properties, crystallite size, and roughness of the deposited fiber, depending on the collector velocity and applied feeding pressure, is revealed. These findings are used to print constructs composed of fibers with different microtopography without affecting the fiber diameter and thus the macroscopic assembly of the printed constructs.

中文翻译：

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控制熔融电写聚（ε-己内酯）纤维的形貌和结晶度

熔体电写 (MEW) 是一种有抱负的 3D 打印技术，在基于纤维的打印技术中具有前所未有的分辨率。它提供了利用熔融聚合物射流直接编写预定义设计的能力，以制造由直径仅为几微米的纤维组成的结构。这些维度使独特的构造属性成为可能。聚（ε-己内酯）（PCL）是一种主要用于生物医学和生命科学应用的半结晶聚合物，是 MEW 最突出的材料，具有出色的印刷性能。尽管 MEW 制造了丰富的熔体电写结构，但仍然缺乏详细的调查，特别是关于宏观和微观水平的纤维分析。因此，这项研究系统地检查了喷丝头直径、进料压力和收集器速度等工艺参数对直径的影响，特别是 PCL 纤维的形貌，并阐明了这些参数如何影响机械性能和结晶度。揭示了沉积纤维的机械性能、微晶尺寸和粗糙度之间的相关性，这取决于收集器速度和施加的进料压力。这些发现用于打印由具有不同微形貌的纤维组成的结构，而不影响纤维直径，从而影响打印结构的宏观组装。和收集器速度对直径，特别是 PCL 纤维的形貌，并阐明这些参数如何影响机械性能和结晶度。揭示了沉积纤维的机械性能、微晶尺寸和粗糙度之间的相关性，这取决于收集器速度和施加的进料压力。这些发现用于打印由具有不同微形貌的纤维组成的结构，而不影响纤维直径，从而影响打印结构的宏观组装。和收集器速度对直径，特别是 PCL 纤维的形貌，并阐明这些参数如何影响机械性能和结晶度。揭示了沉积纤维的机械性能、微晶尺寸和粗糙度之间的相关性，这取决于收集器速度和施加的进料压力。这些发现用于打印由具有不同微形貌的纤维组成的结构，而不影响纤维直径，从而影响打印结构的宏观组装。