Abstract
In this paper, the Maxwell–Wagner effect and the charge characteristics of the heterogeneous interface at the action of higher electric field and elevated temperature are investigated by means of electret technology. A composite membrane with a double-layer structure of a polypropylene (PP) film and a fluorinated ethylene propylene copolymer (FEP) film was made. After being polarized under electric field and elevated temperature, the component PP and FEP films of the composite membranes were separated. The charge density of the PP and FEP films was measured to analyze the characteristics of interfacial charge in the composite membrane. Experimental results directly prove that the charge characteristics at the interface of the composite membranes are consistent with the result calculated by the Maxwell–Wagner effect. The polarity of the interfacial charge can be switched by changing the polarity of the polarizing voltage. The characteristics of the accumulated interfacial charge are strongly dependent on the conductivity, which is affected by the temperature and the polarizing electric field. A new phenomenon, that is, the measured charge density is much higher than that calculated by the Maxwell–Wagner effect, is found. The reason is ascribed to the electret effect from the FEP and PP films. This research provides a new insight into the charge characteristics at the heterogeneous interface.
Highlights
The measured charge density reflects the overall electret properties of the films, rather than just the interface charge features. This illustrates that the electret effect is dominant for the charge characteristics of the composite membrane composed of different dielectric materials
The results presented here further prove that the electret effect is dominant for the characteristics of interfacial charges in the composite membrane composed of different dielectric materials
The experimental results show that the charge characteristics at the interface of the PP–fluorinated ethylene propylene copolymer (FEP) composite membrane are in accordance with the theoretical analysis according to the Maxwell–Wagner effect
Summary
A heterogeneous interface composed of different dielectric materials is a common structure in electronic devices and energy systems, such as organic field effect transistors (OFETs), solar cells, high-performance supercapacitors, and high-voltage transmission cable systems. The study on the dynamic characteristics of charges at interfaces is critical for improving the performance of such devices. For example, the carrier transit time and charging time of OFETs are determined by the charge accumulating effect. The charge transfer mechanism at the interface of photoelectric materials is related to its photoelectric conversion efficiency. The charging efficiency of supercapacitors is limited by the charge transfer performance at their interfaces. In cable systems, the present charges at the dielectric interfaces result in enhancement of the local electric field, which in turn leads to degradation of the dielectrics and eventually electrical breakdown.. A heterogeneous interface composed of different dielectric materials is a common structure in electronic devices and energy systems, such as organic field effect transistors (OFETs), solar cells, high-performance supercapacitors, and high-voltage transmission cable systems.. Charges will accumulate at heterogeneous interfaces of dielectric materials with different permittivities and conductivities. The PEA technology does not directly reveal the dynamic characteristics of charges at heterogeneous interfaces under high electric field and elevated temperature. The polarity of the measured charge at dielectric interfaces agrees with the Maxwell–Wagner effect; the amount of charge accumulated at the interfaces is often quite different from what is expected by the Maxwell–Wagner effect.. After polarization under high electric field and elevated temperature, the double-layer structures were peeled off and separated into PP and FEP films. The charge density of the PP and FEP films was measured to characterize the formation of interfacial charges at the heterogeneous interface of the composite membrane
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
