Resumen de Inflating/deflating drops
A water drop on a superhydrophobic surface features a different value of the contact angle (i.e., the angle between the surface of the drop and the supporting surface, where they meet) depending on its dynamical status. The drop is inflated (a) or deflated (b) by means of a needle [detail in (d)] connected to a syringe. In the inflating phase (a), the contact angle (known as the “advancing angle”) is greater than that of the deflating phase (b), known as the “receding angle.” The difference is also evident in the contact between the drop surface and the needle. The images are taken (c) by a Nikon D850 camera equipped with a micro lens (focal length f = 105 mm). The supporting surface (c) is made superhydrophobic with finely ground “magic sand.”
