Apparent fracture/adhesion energy of interfaces with periodic cohesive interactions
Apparent fracture/adhesion energy of interfaces with periodic cohesive interactions
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DOI：
10.1098/rspa.2007.0240
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发表时间：
2008-03-08
影响因子：
3.5
通讯作者：
Huajian Gao
中科院分区：
文献类型：
--
作者：
Chen, Bin;Xinghua Shi;Huajian Gao
具有周期性内聚相互作用的界面的表观断裂/粘附能对于理解周期性粘附斑块（例如微米和纳米结构表面之间）的粘附具有普遍意义。这类问题有两个重要的长度尺度：一个对应于内聚相互作用的周期，另一个是沿界面的裂纹尖端附近的内聚区的大小。通过理论考虑和数值模拟，我们表明，表观断裂/粘附能取决于内聚相互作用周期与内聚区尺寸之间的比率：如果前者远小于后者，则它等于界面的平均内聚能，但如果相反，则成为局部内聚能的峰值。这一预测已通过对通过周期性离散粘附补片粘附在基材上的薄膜/条带的剥离进行的数值模拟得到证实。我们的分析还为最近的分子动力学模拟提供了解释，该模拟表明粘附在石墨片上的单链 DNA (ssDNA) 的表观粘附能等于 ssDNA 与基底之间范德华相互作用能的峰值，而不是平均值。
The apparent fracture/adhesion energy of an interface with periodic cohesive interactions is of general interest to understanding adhesion via periodic adhesion patches (e.g. between micro- and nanostructured surfaces). There are two important length scales for this class of problems: one corresponds to the period of cohesive interaction and the other is the size of the cohesive zone near the tip of a crack along the interface. By theoretical considerations and numerical simulations, we show that the apparent fracture/adhesion energy depends on the ratio between the period of cohesive interaction and the cohesive zone size: it is equal to the average cohesive energy of the interface if the former is much smaller than the latter but becomes the peak value of the local cohesive energy when the opposite is true. This prediction has been confirmed by numerical simulations on the peeling of a thin-film/strip adhering on a substrate via periodic discrete adhesion patches. Our analysis also provides explanations for a recent molecular dynamics simulation which showed that the apparent adhesion energy of a single-stranded DNA (ssDNA) adhering on a graphite sheet is equal to the peak, rather than the average, value of the van der Waals interaction energy between the ssDNA and the substrate.