Assembling Conductive PEBA Copolymer at the Continuous Interface in Ternary Polymer Systems: Morphology and Resistivity

Two ternary blend systems of low-density polyethylene/poly­(ether-block-amide)/polyethylene terephthalate (LDPE/PEBA/PET) and LDPE/PEBA/polyvinylidene fluoride (PVDF) are prepared by melt blending to thermodynamically assemble the ionically conductive PEBA copolymer at the continuous interface. The LDPE/PEBA/PET blend demonstrates weak partial wetting and a novel morphology transition to complete wetting was observed as the PEBA composition increases from 3% to about 10%. The phenomena can be explained by a mechanism based on the competition between dewetting and coalescence of the PEBA phase at the interface. In the completely wet LDPE/PEBA/PVDF system, a minimum concentration is required to form intact PEBA layers with a thickness of ∼100 nm. Assembling PEBA at the interface of the ternary systems results in the formation of conductive pathways of very low percolation thresholds and thus leads to a significant reduction in the resistivity for both ternary systems as compared to binary blends with PEBA. A particularly sharp drop in resistivity is observed for the complete wetting morphology of LDPE/PEBA/PVDF.