2D Coarsening in Phase-Separated Polymer Solutions: Dependence on Distance from Criticality

Polymer solutions of various compositions have been phase separated in two dimensions in order to monitor the growth rate of the domain size $d$ associated with coarsening in restricted dimensions. For off-critical solutions, $d$ grows approximately as $t^{1/3}$, consistent with theory. For near-critical solutions, $d$ grows approximately as $t^{1/3}$ at early times, followed by a crossover to a rate that is consistent with the $t^{2/3}$ growth rate reported in some numerical studies. The early-time coarsening of critical solutions is dominated by critical wetting and a highly bimodal size distribution, making measurements of $d$ difficult to obtain.