There exist unavoidable drawbacks in the common methods to explore the phase behavior of multi-component polymer systems. Instead

the dynamic rheology research in this field has unique advantages over those methods. This methodology is theoretically based on the fact that

for the multi-component polymer systems exhibiting critical phase behavior (LCST

UCST) or micro-phase separation

their dynamic rheological response under the small strain confition is very sensitive to the formation and evolution of the morphology and structure during the phase separation process

and the presence of the heterogeneous structure leads to the different viscoelastic relaxation behavior from the corresponding homogeneous counterparts in the long time relaxation region. That is

it deviates from the classical linear viscoelastic theoretical models by the enhanced elasticity

much longer relaxation time and breakdown of time-temperature superposition principle (TTS) . The advances in studies on the phase behavior of multi-component polymer systems by such dynamic rheology methods as Hah plot

Cole-Cole plot

breakdown of TTS and

G′~ T

plot were reviewed in this paper.