  A first order phase transition from nuclear matter to antikaon condensed
matter may proceed through thermal nucleation of a critical droplet of antikaon
condensed matter during the early evolution of proto neutron stars (PNS).
Droplets of new phase having radii larger than a critical radius would survive
and grow, if the latent heat is transported from the droplet surface to the
metastable phase. We investigate the effect of shear viscosity on the thermal
nucleation time of the droplets of antikaon condensed matter. In this
connection we particularly study the contribution of neutrinos in the shear
viscosity and nucleation in PNS.
