Dependence of doubly curved regions on drying method in the fabrication of long-side rolled-up III-V microtubes

Through improving fabrication process, short-side rolling phenomenon has been eliminated, and well-aligned long-side rolled-up III-V microtube arrays have been achieved. Finite element method (FEM) has been exploited to simulate the evolution of strain energy in the entire self-rolling process, showing that the difference of strain-released regions is the major factor that determines the rolling direction. Meanwhile, the doubly curved regions have been observed around the openings of air-dried microtubes but do not exist on the microtubes dried in critical point dryer, which demonstrates this structural deformation results not from the release of residual strain energy but from the surface tension. (C) 2013 AIP Publishing LLC.