  A continuum-space bead-spring model is used to study the phase behavior of
binary blends of homopolymers and the structure of the interface between the
two immiscible phases. The structure of the interface is investigated as a
function of immiscibility, chain length, and system size. Capillary waves are
observed and their measurement allows us to determine the surface tension
$\gamma$. We propose a more universal method of measuring the interfacial width
in terms of second moments of the different contributions to the first
derivative of the interfacial profile. Predictions of this method are directly
verified. The effect of chain length on the surface tension is also studied.
