The presence of an ionic liquid in the plasticized polylactide (PLA) contributes to enhancement of dielectric permittivity due to its electrical conductivity. Phase separation, induced by thermal annealing and mechanical stretching, respectively, can further enhance dielectric permittivity. It offers opportunities to monitor phase separation in the ionic liquid plasticized PLA by dielectric spectroscopy. Phase separation is increased with the extent of crystallization in the PLA matrix upon thermal annealing, so does dielectric permittivity. Formation of mesophase and crystals is strain dependent during mechanical stretching of the plasticized PLA. Correspondingly, dielectric permittivity and phase separation also show a dependence on the strain. (C) 2016 Elsevier Ltd. All rights reserved.