Scalable self-assembly process for the fabrication of sub-millimetre three-dimensional cylindrical tubes

The analysis, simulation and experimental fabrication of three-dimensional (3D) cylindrical tubes formed from 2D aluminium/silicon dioxide (Al/SiO2) substrates are presented. The photolithographically fabricated planar Al/SiO2 substrates bend under residual mechanical stress after release, self-assembling into 3D cylindrical tubes. They present an analytical model that allows them to reliably predict the resulting radius of curvature of bi-layer Al/SiO2 tubes with uniform cross-sections, and provides an approximate solution for SiO2 substrates with patterned Al cross-sections. Finite element analysis simulations and measurements of fabricated tubes show agreement with the model. In addition, they show through a series of batch experiments that the self-assembly process is repeatable with proper design of the substrates.