Effect of Halloysite Nanotubes on the Rheological and Phase Separation Behaviors in a Poly(ethylene oxide)/Ionic Liquid Mixture.

A series ternary composites of poly(ethylene oxide)/ionic liquid 30/70 (P30) with uniformly dispersed halloysite nanotubes (HNTs) are investigated in the homogeneous and two‐phase regions. For P30/HNTs composites, a relatively lower percolation threshold about 3 wt% of HNTs loading is observed in the single‐phase region of P30. Beyond the percolation threshold, the steady shear flow exhibits two shear‐thinning regions due to the coupled relaxation of HNTs network and polymer entanglement. In the two‐phase region of P30, the mobility of ionic liquids (ILs) can be impeded accounting for the filler network forming. Not only the phase recovery during cyclic heating–cooling treatment near the phase boundary is accelerated, but also the phase separation kinetics is significantly retarded owing to HNTs dispersed in the PEO‐rich phase impeding the escaping of ILs from PEO phase. The lower storage modulus G′ for P30/HNTs‐4wt% compared to P30/HNTs‐3wt% in a two‐phase region is connected with the competition between the filler contribution and additional elasticity induced by phase separation. [ABSTRACT FROM AUTHOR]