Large-scale microsegregation in polyacrylamide gels (spinodal gels)

Abstract

Exceptionally large pore sizes have recently been reported for polyacrylamide gels grown in the presence of polyethylene glycol. We present small angle static light scattering measurements performed during the evolution of this peculiar gelation process. We give evidence that the large pores are generated by a microsegregation process caused by the competition between gelation and a phase separation of the polymers solution. The separation occurs via spinodal decomposition, and the size of the pores is determined by the stage at which the decomposition is stopped by the gelation process.