Dynamics of mixing between partially miscible polymers

We have measured the time dependence of interface formation between two polymers, below their critical temperature for phase separation, using the ²H{(}³$He${,}⁴$He${)}¹$H nuclear reaction as a direct profiling technique. We find that the width of the interface initially increases with time as ${t}^{{{α}}}$, where the exponent {α}=0.34±{}0.06 is significantly lower than its value of 0.5 for free diffusion.