  In the present communication we report the monolayer characteristics of
pyrene mixed with stearic acid (SA) at the air-water interface. The monolayer
properties are investigated by recording and analyzing the surface
pressure-area per molecule isotherm (pi-A) of the pyrene-SA mixed films. It is
observed that the pyrene and SA are miscible in the mixed monolayer. This
miscibility/nonideality leads to phase separation between the constituent
components (pyrene and SA). BAM image of the mixed monolayer confirms the
miscibility or nonideal mixing at the mixed monolayer.
