Tsao Chia-Wen, Wu Zheng-Kun
Department of Mechanical Engineering, National Central University, Taoyuan City 32001, Taiwan.
Polymers (Basel). 2020 Nov 2;12(11):2574. doi: 10.3390/polym12112574.
Polymer-based micromolding has been proposed as an alternative to SU-8 micromolding for microfluidic chip fabrication. However, surface defects such as milling marks may result in rough microchannels and micromolds, limiting microfluidic device performance. Therefore, we use chemical and mechanical methods for polishing polymer microchannels and micromolds. In addition, we evaluated their performance in terms of removing the machining (milling) marks on polymer microchannel and micromold surfaces. For chemical polishing, we use solvent evaporation to polish the sample surfaces. For mechanical polishing, wool felt polishing bits with an abrasive agent were employed to polish the sample surfaces. Chemical polishing reduced surface roughness from 0.38 μm (0 min, after milling) to 0.13 μm after 6 min of evaporation time. Mechanical polishing reduced surface roughness from 0.38 to 0.165 μm (optimal pressing length: 0.3 mm). As polishing causes abrasion, we evaluated sample geometry loss after polishing. Mechanically and chemically polished micromolds had optimal micromold distortion percentages of 1.01% ± 0.76% and 1.10% ± 0.80%, respectively. Compared to chemical polishing, mechanical polishing could better maintain the geometric integrity since it is locally polished by computer numerical control (CNC) miller. Using these surface polishing methods with optimized parameters, polymer micromolds and microchannels can be rapidly produced for polydimethylsiloxane (PDMS) casting and thermoplastic hot embossing. In addition, low-quantity (15 times) polymer microchannel replication is demonstrated in this paper.
基于聚合物的微成型已被提议作为用于微流控芯片制造的SU-8微成型的替代方法。然而，诸如铣削痕迹等表面缺陷可能会导致微通道和微模具粗糙，从而限制微流控设备的性能。因此，我们使用化学和机械方法对聚合物微通道和微模具进行抛光。此外，我们评估了它们在去除聚合物微通道和微模具表面加工（铣削）痕迹方面的性能。对于化学抛光，我们使用溶剂蒸发来抛光样品表面。对于机械抛光，使用带有研磨剂的羊毛毡抛光钻头来抛光样品表面。化学抛光使表面粗糙度从0.38μm（铣削后0分钟）在蒸发6分钟后降至0.13μm。机械抛光使表面粗糙度从0.38降至0.165μm（最佳压制长度：0.3mm）。由于抛光会造成磨损，我们评估了抛光后样品几何形状的损失。机械抛光和化学抛光的微模具的最佳微模具变形百分比分别为1.01%±0.76%和1.10%±0.80%。与化学抛光相比，机械抛光可以更好地保持几何完整性，因为它是通过计算机数控（CNC）铣床进行局部抛光的。使用这些具有优化参数的表面抛光方法，可以快速生产用于聚二甲基硅氧烷（PDMS）浇铸和热塑性热压印的聚合物微模具和微通道。此外，本文还展示了低数量（15次）的聚合物微通道复制。
