Polymer migration to the film surface during the melt processing of polymer blends is an important phenomenon, but has been limited in study. In this work, melt extruded cast films of conductive poly (ether-block-amide) (PEBA) with low-density polyethylene (LDPE) and polystyrene (PS) are prepared and the critical roles of phase continuity, interfacial tension and viscosity on PEBA surface migration are studied. When blended with high viscosity LDPEs, PEBA tends to migrate to the film surface, but significant surface enrichment only occurs at high PEBA continuities (typically > 50%). A possible surface migration mechanism based on the draining of PEBA through the connected networks is proposed and the migration process is facilitated by high interfacial tension. In compatibilized LDPE/PEBA and in PS/PEBA, the surface migration of PEBA is fully suppressed even at high continuity levels due to the low interfacial tension between the components. The surface resistivities of the binary blends are critically determined by the continuity of PEBA with a limited influence from surface enrichment. It appears that the continuity threshold to influence surface resistivity is lower than that for surface migration. A ternary LDPE/PS/PEBA blend with double percolation can simultaneously reduce the film surface resistivity and control PEBA surface migration by confining PEBA within a continuous low interfacial tension PS phase. (C) 2017 Elsevier Ltd. All rights reserved.