Viscoelastic interface motion in semidilute polymer solutions

We study interface motion in phase separated semidilute polymer solutions near the critical point. We derive the non-Markovian equation for motion of an interface taking into account the viscoelastic effects due to the transient polymer network and the hydrodynamic interaction between interfaces. This equation indicates that the velocity of an interface is affected by the history of the past velocity when the characteristic length scale of domains is shorter than d ₀ ^-1ε _ve ², where d ₀ is the capillary length and ε _ve is the viscoelastic length. We also study growth of a droplet in metastable polymer solutions. The growth is much decelerated when the radius of a droplet is smaller than d ₀ ^-1ε _ve ².