Effect of prestrains on swelling-induced buckling patterns in gel films with a square lattice of holes
Effect of prestrains on swelling-induced buckling patterns in gel films with a square lattice of holes
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DOI：
10.1016/j.ijsolstr.2015.01.015
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发表时间：
2015-04
影响因子：
3.6
通讯作者：
D. Okumura;Takahiro Inagaki;N. Ohno
中科院分区：
文献类型：
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作者：
D. Okumura;Takahiro Inagaki;N. Ohno
我们研究了预应变对具有正方形孔洞的聚合物薄膜中膨胀诱导的屈曲模式的影响。为了重现Zhang等人(2008)进行的实验，聚二甲基硅氧烷(PDMS)薄膜在晶格方向的面内单轴拉伸中预应变，然后用甲苯膨胀。有限元分析采用聚合物凝胶平衡的非均匀场理论，并借助于人工阻尼。在广义平面应变假设下，分析了由2×2和10×10个单胞组成的周期单元。对10×10单胞的分析表明，随着预应变ε=0、0.2、0.4和0.6的增加，所产生的屈曲图案演变为钻石板形(ε=0)、轻微变形的钻石板形(ε=0.2)、圆和线的二元图案(ε=0.4)和单调的椭圆图案(ε=0.6)。这些预测与实验非常吻合。2×2晶胞表明，这些不同的花样在向钻石板状花样转变的过程中以过渡态的形式不断出现，单轴拉伸的预应变延迟了花样转变的开始，平衡膨胀中断了花样转变的进程。参数研究表明，对预应变的模式依赖源于固有的溶胀特征，是所选聚合物和溶剂的特定组合的结果。
We investigate the effect of prestrains on swelling-induced buckling patterns in polymeric films with a square lattice of holes. To reproduce experiments conducted by Zhang et al.(2008), poly (dimethylsiloxane)(PDMS) films are pre-strained in in-plane uniaxial tension in a lattice direction, and subsequently swelled by toluene. Finite element analysis is performed using an inhomogeneous field theory of polymeric gels in equilibrium, and with the aid of artificial damping. Periodic units consisting of 2× 2 and 10× 10 unit cells are analyzed under a generalized plane strain assumption. Analysis of the 10× 10 unit cell shows that the resulting buckling pattern depends on the increase in prestrain of ε= 0, 0.2, 0.4 and 0.6, evolving as a diamond plate pattern (ε= 0), a slightly distorted diamond plate pattern (ε= 0.2), a binary pattern of circles and lines (ε= 0.4), and a monotonous pattern of ellipses (ε= 0.6). These predictions are in very good agreement with experiments. The 2× 2 unit cell reveals that these different patterns appear continuously as transitional states during transformation into diamond plate patterns; prestrains in uniaxial tension delay the onset of the pattern transformation and equilibrium swelling interrupts the progress of the transformation. Parametric studies demonstrate that the pattern dependence on prestrains originates from intrinsic swelling features, and is a consequence of a particular combination of the selected polymer and solvent.