Yang Bin, Sharp James S, Smith Mike I
School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD UK.
Sci Rep. 2016 Aug 25;6:32296. doi: 10.1038/srep32296.
Films formed through the drying of nanoparticle suspensions release the build-up of strain through a variety of different mechanisms including shear banding, crack formation and delamination. Here we show that important connections exist between these different phenomena: delamination depends on the dynamics of crack hopping, which in turn is influenced by the presence of shear bands. We also show that delamination does not occur uniformly across the film. As cracks hop they locally initiate the delamination of the film which warps with a timescale much longer than that associated with the hopping of cracks. The motion of a small region of the delamination front, where the shear component of interfacial crack propagation is believed to be enhanced, results in the deposition of a complex zig-zag pattern on the supporting substrate.
通过纳米颗粒悬浮液干燥形成的薄膜会通过多种不同机制释放应变积累，这些机制包括剪切带形成、裂纹形成和分层。在此我们表明，这些不同现象之间存在重要联系：分层取决于裂纹跳跃的动力学，而裂纹跳跃又受剪切带的存在影响。我们还表明，分层并非在整个薄膜上均匀发生。当裂纹跳跃时，它们会局部引发薄膜的分层，薄膜会以比裂纹跳跃相关时间尺度长得多的时间尺度发生翘曲。在分层前沿的一个小区域的运动，据信在该区域界面裂纹扩展的剪切分量会增强，这会在支撑基板上沉积出复杂的之字形图案。
