A plethora of polymers are excellent candidates that can be utilized to build various terahertz (THz) based systems for sensing and microfluidics. SU-8 is a versatile epoxy-based polymer with excellent properties, such as biocompatibility and good mechanical properties. Nevertheless, the impact of curing parameters on the THz absorption characteristics of SU-8 remains uncertain. This study explores the impact of various curing conditions on the THz absorption properties of SU-8. The aim is to establish a correlation between THz absorption and the polymer's cross-linking characteristics. Therefore, three key curing parameters have been examined: time, temperature, and ultraviolet (UV) exposure dose. The SU-8 samples that are cured under different conditions are examined using THz Time-Domain Spectroscopy (THz-TDS) to estimate the THz absorption coefficient. Next, the swelling experiment is conducted to evaluate the polymer cross-linking of the cured samples. The results show that curing conditions and, thus, cross-linking routines significantly influence THz wave propagation and attenuation within SU-8 samples. The findings recommended using an optimal curing dose for SU-8 spanning 1240 mJ/cm2 to 1860 mJ/cm2 which results in a relatively lower absorption coefficient while still maintaining a higher state of cross-linking. This research establishes a crucial link between SU-8 processing and its THz response. It can lay the foundation for tailored SU-8 polymer with optimized THz transmission for novel and customized biosensing and microfluidic devices.

中文翻译：

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SU-8固化参数对太赫兹吸收特性的影响


许多聚合物都是极好的候选者，可用于构建各种基于太赫兹 (THz) 的传感和微流体系统。 SU-8 是一种多功能环氧基聚合物，具有优异的性能，例如生物相容性和良好的机械性能。然而，固化参数对 SU-8 太赫兹吸收特性的影响仍不确定。本研究探讨了不同固化条件对 SU-8 太赫兹吸收性能的影响。目的是建立太赫兹吸收与聚合物交联特性之间的相关性。因此，我们检查了三个关键的固化参数：时间、温度和紫外线 (UV) 暴露剂量。使用太赫兹时域光谱 (THz-TDS) 检查在不同条件下固化的 SU-8 样品，以估计太赫兹吸收系数。接下来，进行溶胀实验以评估固化样品的聚合物交联。结果表明，固化条件以及交联程序显着影响 SU-8 样品内的太赫兹波传播和衰减。研究结果建议对 SU-8 使用 1240 mJ/cm2 至 1860 mJ/cm2 的最佳固化剂量，这会导致相对较低的吸收系数，同时仍保持较高的交联状态。这项研究在 SU-8 处理与其太赫兹响应之间建立了至关重要的联系。它可以为定制的 SU-8 聚合物奠定基础，该聚合物具有优化的太赫兹传输，适用于新型和定制的生物传感和微流体设备。