摘要
Perfect Archimedes spiral cracks at micrometer scales are found in a colloid film of several hundred nanometers in thickness coated on a glass substrate.To explain the formation of this kind of spiral crack,the relation between the geometrical properties of the Archimedes spiral and the growth kinematics of the spiral cracks are analyzed.Meanwhile,the initiation and propagation of the spiral cracks are speculated upon logically from the specific material system based on sufficient evidence.In addition,we introduce a new cracking phenomenon and provide an insight into the new mechanism for crack propagation in soft material nano films coated on stiff substrates.
基金
Supported by the National Basic Research Program of China under Grant Nos 2010CB631005,2011CBG0C105
the National Natural Science Foundation of China under Grant Nos 11172151,11232008,11072152,11272175
the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20090002110048.Tsinghua University Initiative Scientific Research Program。
