Microscale Templating of Materials across Electrospray Deposition Regimes
Microscale Templating of Materials across Electrospray Deposition Regimes
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DOI：
10.3390/coatings13030599
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发表时间：
2023-03-01
期刊：
影响因子：
3.4
通讯作者：
Singer, Jonathan P.
中科院分区：
文献类型：
--
作者：
Grzenda, Michael J.;Atzampou, Maria;Singer, Jonathan P.
电喷雾沉积（ESD）使用强电场从溶液和分散体中产生一代又一代的单分散液滴，这些液滴被驱动到接地的基材上。当输送软材料时，生长薄膜的行为取决于薄膜耗散电荷的能力，这与介电材料的迁移率密切相关。因此，电喷雾存在三种状态：电润湿状态、带电熔体状态和自限状态。在自我限制的情况下，最近的研究表明，这些喷雾剂的靶向性允许无电晕的3D涂层。虽然在微米尺度上的静电放电模式已经研究了几十年，最典型的是通过使用绝缘口罩，但没有对这种现象进行跨喷涂制度的比较研究。在这里，我们使用了由光栅组成的测试模式，其特征尺寸（30-240 μ m）和间距（1/3x-9x）不等，以比较不同区域的材料。使用轮廓仪扫描喷涂图案，提取密度、平均高度和特异性。从这些结果可以看出，与电润湿和带电熔体喷雾相比，在自限制状态下沉积的材料在小特征上表现出最高的均匀性和特异性。因此，自限制电喷雾沉积最适合于修改预制电极图案。
Electrospray deposition (ESD) uses strong electric fields to produce generations of monodisperse droplets from solutions and dispersions that are driven toward grounded substrates. When soft materials are delivered, the behavior of the growing film depends on the film's ability to dissipate charge, which is strongly tied to its mobility for dielectric materials. Accordingly, there exist three regimes of electrospray: electrowetting, charged melt, and self-limiting. In the self-limiting regime, it has been recently shown that the targeted nature of these sprays allows for corona-free 3D coating. While ESD patterning on the micron-scale has been studied for decades, most typically through the use of insulating masks, there has been no comparative study of this phenomenon across spray regimes. Here, we used test-patterns composed of gratings that range in both feature size (30-240 mu m) and spacing (1/3x-9x) to compare materials across regimes. The sprayed patterns were scanned using a profilometer, and the density, average height, and specificity were extracted. From these results, it was demonstrated that material deposited in the self-limiting regime showed the highest uniformity and specificity on small features as compared to electrowetting and charged melt sprays. Self-limiting electrospray deposition is, therefore, the best suited for modification of prefabricated electrode patterns.