Evaporation induced two-dimensional buckling within liquid droplet

Evaporation of a liquid droplet containing a thin layer of surfactants atop could generate two-dimensional buckling on surfaces. Herringbone features were produced via embedded nanoparticle beds. We assign transient surface tension as the driving force for such a phenomenon. Considering the surfactant layer as a thin elastic film, a continuum model is employed to calculate the mechanical properties of the layer. Particularly, we estimated an elastic modulus of 4 GPa for the surfactant layer, indicating rather strong mechanical properties of these small molecules when they are close packed to form supramolecules via noncovalent binding.