Effects of Surface Energy Reducing Agents on Adhesion Force in Liquid Bridge Microstereolithography
Effects of Surface Energy Reducing Agents on Adhesion Force in Liquid Bridge Microstereolithography
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DOI：
10.1016/j.addma.2020.101522
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发表时间：
2020-12
影响因子：
11
通讯作者：
A. Alamdari;Jeongwoo Lee;Myoeum Kim;Md. Omar Faruk Emon;A. Dhinojwala;Jae-Won Choi
中科院分区：
文献类型：
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作者：
A. Alamdari;Jeongwoo Lee;Myoeum Kim;Md. Omar Faruk Emon;A. Dhinojwala;Jae-Won Choi
投影微立体光刻（MSL）是一种用于制造三维（3D）微结构的逐层制造工艺。在这个过程中，每一层光反应性液体树脂通过调制的紫外线（UV）光通过数字光调制器件（DMD）进行交联。尽管MSL的能力，有一些缺点，如不兼容的高粘度材料，长的制造时间，大的材料消耗，和氧气抑制。为了解决这些问题，液桥微立体光刻（LBMSL）已被提出作为一种无缸工艺，其涉及使用由两个基板之间的毛细管桥支撑的液体树脂。LBMSL工艺中最重要的制造步骤之一是将固化层从上透明基板上分离，而不会在3D打印过程中对结构造成任何损坏。本文研究了使用小分子添加剂，表面能降低剂（SERA），倾向于向透明基板迁移，并减少在这个界面上的粘附力。这已经通过一系列附着力测量和材料表征方法得到了证明。使用接触角测量和X射线光电子能谱（XPS）研究了SERA分子的迁移。此外，拉伸测量显示，由于在配方中添加SERA，对树脂的机械性能没有不利影响。已经制造了多个3D微结构来说明添加SERA以减少LBMSL中树脂对透明基板的粘附的优点。
Projection microstereolithography (MSL) is a layer-by-layer manufacturing process used to fabricate three-dimensional (3D) microstructures. In this process, each layer of a photoreactive liquid resin is crosslinked by modulated ultraviolet (UV) light through a digital micromirror device (DMD). Despite the capabilities of MSL, there are some drawbacks such as incompatibility with highly viscous materials, long manufacturing time, large material consumption, and oxygen inhibition. To address these issues, liquid bridge microstereolithography (LBMSL) has been proposed as a vat-free process, which involves using a liquid resin supported by a capillary bridge between two substrates. One of the most important manufacturing steps in the LBMSL process is to detach the cured layers from the upper transparent substrate, without causing any damage to the structure during the 3D printing process. This paper has investigated the use of a small molecule additive, a surface energy reducing agent (SERA) that tends to migrate toward the transparent substrate and reduces adhesion at this interface. This has been proven through a series of adhesion force measurements and material characterization methods. The migration of SERA molecules has been studied using contact angle measurements and x-ray photoelectron spectroscopy (XPS). In addition, tensile measurements reveal that there are no detrimental effects on the mechanical properties of the resin due to adding SERA in the formulation. Multiple 3D microstructures have been fabricated to illustrate the advantage of adding SERA to reduce the adhesion of the resin to the transparent substrate in LBMSL.