Polymer mechanics and characterization is an active area of research where a keen effort is directed towards gaining a predictive and correlative relationship between the applied loads and the specific conformational motions of the macromolecule chains. Therefore, the objective of this research is to introduce the preliminary results based on a novel technique to in situ probe the mechanical properties of polymers using non-invasive, non-destructive, and non-contact terahertz spectroscopy. A dielectric elastomer actuator (DEA) structure is used as the loading mechanism to avoid obscuring the beam path of transmission terahertz time-domain spectroscopy. In DEAs, the applied voltage results in mechanical stresses under the active electrode area with far-reaching stretching in the passive area. Finite element analysis is used to model and simulate the DEA to quantify the induced stresses at the observation site over a voltage range spanning from 0 V to 3000 V. Additionally, a novel analysis technique is introduced based on the Hilbert-Huang transform to exploit the time-domain signals of the ultrathin elastomeric film and to defy the limits set forth by the current state-of-the-art analysis techniques. The computational result shows a nonlinear relationship between the effective stresses and the applied voltage. Analysis of the terahertz time-domain signals shows a shift in the delay times and a decrease in signal peak amplitudes, whereas these characteristics are implicitly related to the change in the index of refraction. In all, the results evidentially signify the interrelationship between the conformational changes and applied mechanical stress.

中文翻译：

---

聚合物中应力引起的构象变化的物理证据

聚合物力学和表征是一个活跃的研究领域，致力于获得所施加载荷与大分子链的特定构象运动之间的预测和相关关系。因此，本研究的目的是介绍基于新技术的初步结果，该技术使用非侵入性、非破坏性和非接触式太赫兹光谱原位探测聚合物的机械性能。介电弹性体致动器 (DEA) 结构用作加载机制，以避免遮挡透射太赫兹时域光谱的光束路径。在 DEA 中，施加的电压会在有源电极区域下产生机械应力，并在无源区域产生深远的拉伸。有限元分析用于对 DEA 进行建模和模拟，以量化观测地点在 0 V 到 3000 V 电压范围内的感应应力。此外，还引入了一种基于 Hilbert-Huang 变换的新型分析技术，以利用超薄弹性薄膜的时域信号，并突破当前最先进的分析技术所规定的限制。计算结果显示了有效应力和施加电压之间的非线性关系。对太赫兹时域信号的分析显示延迟时间发生变化，信号峰值幅度减小，而这些特性与折射率的变化隐含相关。在所有，