Song Kyu, Cho Nak-Kyun, Park Keun, Kim Chung-Soo
Department of Manufacturing Systems and Design Engineering, Seoul National University of Science and Technology (SeoulTech), Seoul 01811, Korea.
Department of Mechanical Systems Design Engineering, Seoul National University of Science and Technology (SeoulTech), Seoul 01811, Korea.
Polymers (Basel). 2022 Jun 12;14(12):2373. doi: 10.3390/polym14122373.
Polydimethylsiloxane (PDMS) is widely utilised as a substrate for wearable (stretchable) electronics where high fatigue resistance is required. Cyclic loadings cause the rearrangement of the basic molecular structure of polymer chains, which leads to changes in the mechanical properties of the PDMS structure. Accordingly, it is necessary to investigate reliable mechanical properties of PDMS considering both monotonic and cyclic loading conditions. This study aims to present the mechanical properties of PDMS films against both monotonic and cyclic loading. The effects of certain parameters, such as film thickness and magnitude of tensile strain, on mechanical properties are also investigated. The test results show that PDMS films have a constant monotonic elastic modulus regardless of the influence of thickness and tensile loading, whereas a cyclic elastic modulus changes depending on experimental parameters. Several material parameters, such as neo-Hookean, Mooney-Rivlin, the third-order Ogden model, and Yeoh, are defined to mimic the stress-strain behaviours of the PDMS films. Among them, it is confirmed that the third-order Ogden model is best suited for simulating the PDMS films over the entire tensile test range. This research makes contributions not only to understanding the mechanical behaviour of the PDMS films between the monotonic and the cycle loadings, but also through providing trustworthy hyperelastic material coefficients that enable the evaluation of the structural integrity of the PDMS films using the finite element technique.
聚二甲基硅氧烷（PDMS）被广泛用作需要高抗疲劳性的可穿戴（可拉伸）电子产品的基底。循环加载会导致聚合物链基本分子结构的重排，从而导致PDMS结构的力学性能发生变化。因此，有必要在考虑单调和循环加载条件的情况下研究PDMS可靠的力学性能。本研究旨在呈现PDMS薄膜在单调和循环加载下的力学性能。还研究了某些参数，如薄膜厚度和拉伸应变大小对力学性能的影响。测试结果表明，无论厚度和拉伸载荷的影响如何，PDMS薄膜都具有恒定的单调弹性模量，而循环弹性模量则根据实验参数而变化。定义了几个材料参数，如neo-Hookean模型、Mooney-Rivlin模型、三阶Ogden模型和Yeoh模型，以模拟PDMS薄膜的应力-应变行为。其中，已证实三阶Ogden模型最适合在整个拉伸试验范围内模拟PDMS薄膜。本研究不仅有助于理解PDMS薄膜在单调和循环加载之间的力学行为，还通过提供可靠的超弹性材料系数，使得能够使用有限元技术评估PDMS薄膜的结构完整性。
