Nanostructure collapse by elasto-capillary instability.

The nanostructure can collapse due to elasto-capillary interactions. On the basis of free energy analysis for three cases, the contact between double beams can be induced by equilibrium contact or instability. In the former mechanism, the beam contact can be achieved by a gradual increase of deformation with increasing the liquid volume. In the latter mechanism, a sudden rise of deformation occurs due to the divergence of the Laplace pressure as the liquid volume exceeds a critical value. For the case of free-fixed beams, the collapse phase diagram is obtained in the structure aspect ratio-liquid volume plane. The collapse by equilibrium contact occurs for a large aspect ratio but that by instability happens for a small aspect ratio. For the case of fixed-fixed beams, the collapse can occur at the midpoint of two beams by instability.