Effects of Viscosity-Controlled Interfacial Mobility on the Coalescence of Immiscible Polymer Blends

The consequences of the interfacial mobility on the coalescence process in immiscible polymer blends was studied. Blends of PIB and PDMS with 10 vol.% PIB were subjected to shear-flow step-down experiments under controlled conditions. The blend was initially sheared at high shear rate to obtain a fine dispersion (small drop size). The shear rate was then stepped down and the coalescence process was monitored by performing repeated SAOS experiments. In the limit of high and low viscosity ratios, the experimental results were in excellent agreement with theory predictions for IMI and FMI conditions. In the intermediate range of viscosity ratio, corresponding to PMI conditions, a smooth transition between the limiting IMI and FMI states was found