Mechanical Mapping of Nanoblisters Confined by Two-Dimensional Materials Reveals Complex Ridge Patterns.

Understanding the mechanics of blisters confined by two-dimensional (2D) materials is of great importance for either fundamental studies or for their practical applications. In this work, we investigate the mechanical properties of nanoscale 2D material blisters using contact-resonance atomic force microscopy (CR-AFM). From the measurement results at the blister centers, the blisters' internal pressures are characterized, which are shown to be inversely proportional to the blisters' sizes. Our measurements agree considerably well with values predicted by theoretical mechanic analyses of the blisters. In addition, high-resolution mechanical mapping with CR-AFM reveals fine, complex ridge patterns of the blisters' confining membranes, which can hardly be distinguished from their topographies. The pattern complexity of a blister system is shown to increase with an increase in its bendability.