Peeling of thin films has been widely used in adhesion measurement, film transfer and bio-inspired design. Most previous studies focused on the peeling of thin films from rigid substrates, but soft substrates are common in practical applications. Herein, we propose a two-dimensional model based on the bilinear cohesive law to characterize the 90-degree peeling of elastic thin films from elastic soft substrates, and obtain theoretical solutions expressed in terms of the Chebyshev series. The theoretical solutions match well with the finite element method results, including the load-displacement curves and the bulging deformation of soft substrates. We find that with decreasing substrate modulus, the maximum peeling force (Pmax) decreases but the steady-state peeling force remains unchanged. With the present solutions, the interfacial strength and fracture energy can be extracted simultaneously from the 90-degree peeling experiments of thin film/soft substrate systems, and then the experimentally measured Pmax for different film thicknesses can be well predicted. Furthermore, we obtain a new power scaling law of Pmax, where the scaling exponent depends on substrate elasticity. These results can help us measure the interfacial properties of thin film/soft substrate systems via peel tests, and regulate their peeling behaviors by interface design.

中文翻译：

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弹性薄膜从弹性软基材上 90 度剥离：理论解和实验验证


薄膜的剥离已广泛用于粘附力测量、薄膜转移和仿生设计。以前的大多数研究都集中在薄膜从刚性衬底上剥离，但软衬底在实际应用中很常见。在此，我们提出了一个基于双线性内聚律的二维模型来表征弹性薄膜从弹性软衬底上 90 度剥离，并获得以切比雪夫级数表示的理论解。理论解与有限元方法的结果非常吻合，包括载荷-位移曲线和软基板的膨胀变形。我们发现，随着基板模量的降低，最大剥离力 （Pmax） 降低，但稳态剥离力保持不变。利用目前的解决方案，可以从薄膜/软衬底系统的 90 度剥离实验中同时提取界面强度和断裂能，然后可以很好地预测不同薄膜厚度的实验测量 Pmax。此外，我们获得了一个新的 Pmax 功率缩放定律，其中缩放指数取决于衬底弹性。这些结果可以帮助我们通过剥离测试测量薄膜/软基底系统的界面特性，并通过界面设计调节它们的剥离行为。