Strain-Engineered Adhesion and Reversible Transfer Printing of Water Droplets and Nanoparticles.

Transfer printing has been playing a crucial role in the fabrication of various functional devices. In spite of the extensive progress in technology, challenges are remaining, in the aspects of accuracy, efficiency, and adaptivity. Here, we propose a reversible transfer printing technique of tailoring adhesion by selectively stretching the surfaces. Through molecular dynamics simulations, we demonstrate the transfer of nanoscale substances such as water droplets, colloids, and nanoparticles between two graphene surfaces with strains switched on and off. We reveal the mechanism of the dynamic behaviors by analyzing the energies and driving forces of the substances during the process of transfer. The work not only advances the fundamental understanding of adhesion but also can inspire applications in the design of next-generation electronic and biomedical devices.