Manifestation of spinodal decomposition in oscillatory shear measurements

The linear dynamic moduli of a PαMSAN/PMMA blend have been measured during spinodal decomposition and the subsequent coarsening of the co‐continuous morphology. The feasibility of probing this morphology development by rheological measurements has been investigated. During phase separation, the storage modulus shows a power law behaviour at low frequency and its value decreases as time proceeds. However, effects of the dynamic measurement on 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 theory.