Manifestation of spinodal decomposition in oscillatory shear measurements

The linear dynamic moduli of a P alpha MSAN/PMMA blend have been measured d uring spinodal decomposition and the subsequent coarsening of the co-contin uous morphology. The feasibility of probing this morphology development by rheological measurements has been investigated. During phase separation, th e storage modulus shows a power law behaviour at low frequency and its valu e decreases as time proceeds. However, effects of the dynamic measurement o n the morphology development have been observed, even for strain amplitudes as low as 0.01. This effect of oscillatory shear on the coarsening of a co -continuous structure is consistent with the predictions of the Doi-Ohta th eory.