4] NPs can introduce extra dissipation due to polarization processes which may involve space charge polarization, dipole polarization, and interfacial polarization
at microwave band.
The two mechanisms are likely to be involved when blood is subject to field and temperature; aggregation and interfacial polarization
In the frequency range from dozens of megahertz to several gigahertz, three main polarization phenomena contribute to the dielectric dispersive behavior of oil bearing reservoirs: the electronic polarization (rock's inherent permittivity), the molecular polarization (brine water molecules) and the interfacial polarization
which is also called Maxwell-Wagner polarization.
At higher frequencies the electron exchange between ferrous and ferric ions cannot follow the alternating field, which causes a decrease in the contribution of interfacial polarization
in dielectric constant, and as a result, we see a decrease in the dielectric constant and dielectric loss factor.
This kind of polarization is called the Maxwell-Wagner or interfacial polarization
Moreover, the contribution of Maxwell-Wagner interfacial polarization
due to heterogerfiety present in the system progressively increases as the measurement frequency is decreased (ref.
The loss factor due to Maxwell-Wagner or interfacial polarization
is gives by Eq.
An additional polarization contribution from the interfaces was proposed in these multicomponent systems even though the origin of the interfacial polarization
is still unclear (probably due to the different conductivity between two components and the resulting charge accumulation at interface) [35, 37], The results demonstrate the promise of blend approaches for tailoring and enhancing the dielectric properties of ferroelectric polymers.
As interfacial polarization
takes place at large scale (mesoscopic scale), it has usually been observed at low frequencies, due to its large relaxation time with respect to electric field frequency at high frequencies.
Higher permittivity values at low frequency can be explained by invoking interfacial polarization
mechanism, akin to that reported for the other composite system in the literature (14-18).
Moreover, the smaller size Al particles/LLDPE composite shows a stronger interfacial polarization
effect, compared to the larger size particles filled one.
The Maxwell-Wagner-Sillars (MWS) interfacial polarization
effect was seen in the dielectric permittivity curve for the two-phase semicrystalline polymer, which was absent for its amorphous counterpart (7).