Morina Edona, Dotter Marius, Döpke Christoph, Kola Ilda, Spahiu Tatjana, Ehrmann Andrea
Department of Textile and Fashion, Polytechnic University of Tirana, 1019 Tirana, Albania.
Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences and Arts, 33619 Bielefeld, Germany.
Nanomaterials (Basel). 2023 Sep 6;13(18):2507. doi: 10.3390/nano13182507.
Nanofiber mats can be electrospun by different techniques, usually subdivided into needle-based and needleless. The latter allow for producing large-area nanofiber mats, e.g., with a width of 50 cm and lengths of several meters, if electrospinning proceeds for several hours, depending on the required thickness. Even spinning smaller samples, however, raises the question of homogeneity, especially if defined mechanical properties or a defined thickness is required, e.g., for filtration purposes. Very often, only the inner parts of such electrospun nanofiber mats are used to avoid too high variation of the nanofiber mat thickness. For this study, we used wire-based electrospinning to prepare nanofiber mats with slightly varying spinning parameters. We report investigations of the thickness and mass per unit area, measured on different positions of needleless electrospun nanofiber mats. Martindale abrasion tests on different positions are added as a measure of the mechanical properties. All nanofiber mats show unexpectedly strong variations of thickness, mass per unit area, and porosity, as calculated from the apparent density of the membranes. The thickness especially varied by nearly one order of magnitude within one sample, while the apparent density, as the most uniform parameter, still showed variations by more than a factor of two within one sample. This shows that even for apparently highly homogeneous areas of such nanofiber mats, variations cannot be neglected for all potential applications.
纳米纤维垫可以通过不同的技术进行电纺，通常分为基于针头和无针头两种。如果电纺持续数小时，后者能够制备大面积的纳米纤维垫，例如宽度为50厘米、长度为几米的垫子，这取决于所需的厚度。然而，即使是纺制较小的样品，也会出现均匀性问题，特别是当需要确定的机械性能或确定的厚度时，例如用于过滤目的。通常，为了避免纳米纤维垫厚度变化过大，仅使用这种电纺纳米纤维垫的内部部分。在本研究中，我们使用基于金属丝的电纺技术，通过略微改变纺丝参数来制备纳米纤维垫。我们报告了对无针头电纺纳米纤维垫不同位置的厚度和单位面积质量的研究。此外，还对不同位置进行了马丁代尔耐磨试验，以衡量其机械性能。所有纳米纤维垫的厚度、单位面积质量和孔隙率均呈现出意外的强烈变化，孔隙率是根据膜的表观密度计算得出的。特别是在一个样品中，厚度变化近一个数量级，而作为最均匀参数的表观密度，在一个样品中仍显示出超过两倍的变化。这表明，即使对于这种纳米纤维垫表面上高度均匀的区域，对于所有潜在应用而言，其变化也不能被忽视。
