NUCLEATION OF SPHERICAL SHELL-LIKE INTERFACES BY 2ND GRADIENT THEORY - NUMERICAL SIMULATIONS

The theory of second gradient fluids (which are able to exert shear st resses also in equilibrium conditions) allows us: (i) to describe both the thermodynamical and the mechanical behavior of systems in which a n interface is present: (ii) to express the surface tension and the ra dius of microscopic bubbles in terms of a functional of the chemical p otential; (iii) to predict the existence of a (minimal) nucleation rad ius for bubbles. Moreover the above theory supplies a 3D-continuum mod el which is endowed with sufficient structure to allow, using the proc edure developed by dell'Isola & Kosinski, construction of a 2D-shell-l ike continuum representing a consistent approximate 2D-model for the i nterface between phases. In this paper we use numerical simulations in the framework of second gradient theory to obtain explicit relationsh ips for the surface quantities typical of 2D-models. In particular, fo r some of the most general two-parameter equations of state, it is pos sible to obtain the curves describing the relationship between surface tension, the thickness, the surface mass density and the radius of th e spherical interfaces between fluid phases of the same substance. The se results allow us to predict the (minimal) nucleation radii for this class of equations of state.