Reversible adhesion stamp can vary its adhesion strength by 1,000 times. Researchers were also successful at printing layers of electronics, that may lead to the development of complex devices in the future. Four pyramids on the stamp press firmly against the surface of an electronic device, the soft tips expand and thus increase the surface-to-surface contact. The stamp can pick up the device and then by returning to its original pyramid shape (removing the adhesive force) the electronic device can be easily transferred to another surface.
Microstructured elastomeric surfaces with reversible adhesion and examples of their use in deterministic assembly by transfer printing
Reversible control of adhesion is an important feature of many desired, existing, and potential systems, including climbing robots, medical tapes, and stamps for transfer printing. We present experimental and theoretical studies of pressure modulated adhesion between flat, stiff objects and elastomeric surfaces with sharp features of surface relief in optimized geometries. Here, the strength of nonspecific adhesion can be switched by more than three orders of magnitude, from strong to weak, in a reversible fashion. Implementing these concepts in advanced stamps for transfer printing enables versatile modes for deterministic assembly of solid materials in micro/nanostructured forms. Demonstrations in printed two- and three-dimensional collections of silicon platelets and membranes illustrate some capabilities. An unusual type of transistor that incorporates a printed gate electrode, an air gap dielectric, and an aligned array of single walled carbon nanotubes provides a device example.