Spontaneous buckling-driven periodic delamination of thin films on soft substrates under large compression

Through a combination of experiments, theoretical modeling, and finite element simulation, we explore the mechanics governing the formation and evolution of periodic buckle-delamination on both micro- and macro-scale by bonding a thin film to an extremely pre-strained soft elastomeric substrate over 400%. We find that upon the large substrate pre-strain release, the deformation in the film follows a three-stage deformation regime, i.e. onset of localized blisters (Stage I), growth through delamination crack propagation to form periodic sinusoidal blisters (Stage II), and transition to post-buckled jig-saw-like blisters under fixed-end compression after crack arrest (Stage III). Related energy-based mechanics models on predicting the evolution and geometry of periodic blisters under moderate and large compression are developed and validated through both experiments and finite element simulation. Finally, we discuss the potential applications of harnessing spontaneous buckle-delamination for interfacial toughness measurement through the metrology of blisters, as well as design of extremely stretchable electronics by achieving an extremely lower value of maximum tensile strain in the buckle-delaminated film. (C) 2018 Elsevier Ltd. All rights reserved.

通过实验、理论建模和有限元模拟相结合的方法，我们研究了在微观和宏观尺度上，将薄膜粘结到预应变超过400%的极软弹性基底上时，周期性屈曲 - 分层形成和演化的力学机制。我们发现，在基底大的预应变释放时，薄膜的变形遵循一个三阶段变形模式，即局部鼓泡的起始（第一阶段），通过分层裂纹扩展生长形成周期性正弦鼓泡（第二阶段），以及在裂纹停止后在固定端压缩下转变为后屈曲的拼图状鼓泡（第三阶段）。我们建立了基于能量的相关力学模型，用于预测在中等和大压缩下周期性鼓泡的演化和几何形状，并通过实验和有限元模拟进行了验证。最后，我们讨论了利用自发屈曲 - 分层通过鼓泡的度量来测量界面韧性的潜在应用，以及通过在屈曲 - 分层薄膜中实现极低的最大拉伸应变值来设计极具拉伸性的电子器件。（C）2018爱思唯尔有限公司。保留所有权利。