372 / 2019-03-14 16:24:21

Depth Profile and Transport of Positive and Negative Charge in Surface (2-D) and Bulk (3-D) Nanocomposite Films

LDPE nanocomposites, MgO nanoparticles, Space charge, Charge transport, Charge stability, Acoustic probing of electric-field profiles, Piezoelectrically generated Pressure Steps (PPSs)

In the present study, the charge distribution and the
charge transport across the thickness of 2- and 3-dimensional
polymer nanodielectrics was investigated. Chemically surfacetreated
polypropylene (PP) films and low-density polyethylene
nanocomposite films with 3 wt % of magnesium oxide
(LDPE/MgO) served as examples of 2-D and 3-D nanodielectrics,
respectively. Surface charges were deposited onto the nonmetallized
surfaces of the one-side metallized polymer films
and found to broaden and to thus enter the bulk of the films
upon thermal stimulation at suitable elevated temperatures. The
resulting space-charge profiles in the thickness direction were
probed by means of Piezoelectrically-generated Pressure Steps
(PPSs). It was observed that the chemical surface treatment of
PP which led to the formation of nano-structures or the use
of bulk nanoparticles from LDPE/MgO nanocomposites enhance
charge trapping on or in the respective polymer films and also
reduce charge transport inside the respective samples.