Effects of surface morphology on space charge formation in low density polyethylene

The effects of a modified surface morphology on space charge formation in low-density polyethylene (LDPE) were investigated with pulsed electro-acoustics. The change in morphology resulting from LDPE crystallization on atomically flat substrates was imaged by atomic force microscopy. An extensive lamellar morphology was observed, which contrasts with the crystal structure formed between PET films. The regular arrangement was confirmed with wide-angle X-ray diffraction. Space charge accumulation was characterized in samples with different surface morphologies. Charge injection occurs in both films, but is much larger in the LDPE-mica films than in the LDPE-PET films, and the difference increases over time. A suppression of current density in the LDPE-mica films was coincident with space charge formation.