  Boiling is the out-of-equilibrium transition which occurs when a liquid is
heated above its vaporization temperature. At the nanoscale, boiling may be
triggered by irradiated nanoparticles immersed in water or nanocomposite
surfaces and often results in micro-explosions. It is generally believed that
nanoscale boiling occurs homogeneously when the local fluid temperature exceeds
its spinodal temperature, around 573 K for water. Here, we employ molecular
dynamics simulations to show that nanoscale boiling is an heterogenous
phenomenon occuring when water temperature exceeds a wetting dependent onset
temperature. This temperature can be 100 K below spinodal temperature if the
solid surface is weakly wetting water. In addition, we show that boiling is a
slow process controlled by the solid-liquid interfacial thermal conductance,
which turns out to decrease significantly prior to phase change yielding long
nucleation times. We illustrate the generality of this conclusion by
considering both a spherical metallic nanoparticle immersed in water and a
solid surface with nanoscale wetting heterogeneities. These results pave the
way to control boiling using nanoscale patterned surfaces.
