An analytical model for shear-enhanced adhesiveless transfer printing

Transfer printing is an important technique for assembling micro/nanomaterials on unusual substrates, with promising applications in the fabrication of stretchable and flexible electronics designed for use in areas such as biomedicine. The process involves retrieval of structures (e.g., micro-devices) from their growth (donor) substrate via an elastomeric stamp (i.e., an element with posts on its surface), and then delivers them onto a different (receiver) substrate. An analytical mechanics model is developed to identify the key parameters for a shear-enhanced mode for transfer printing. The results predict that the pull-off force decreases linearly with increasing shear strain in the post, or with shear displacement across the stamp. This prediction agrees well with the experiments.