Study on Micro Interfacial Charge Motion of Polyethylene Nanocomposite Based on Electrostatic Force Microscope.

Bai Han,Chuqi Yin,Jiaxin Chang,Penghao Lv,Wei Song,Xuan Wang,Zhi Sun

doi:10.3390/polym11122035

Abstract

The interface area of nano-dielectric is generally considered to play an important role in improving dielectric properties, especially in suppressing space charge. In order to study the role of interface area on a microscopic scale, the natural charge and injected charge movement and diffusion on the surface of pure LDPE and SiO2/LDPE nanocomposite were observed and studied by gradual discharge under electrostatic force microscope (EFM). It was detected that the charge in SiO2/LDPE nanocomposite moved towards the interface area and was captured, which indicates that the charge was trapped in the interface area and formed a barrier to the further injection of charge and improving the dielectric performance as a result. Moreover, pulsed electro-acoustic (PEA) short-circuited test after charge injection was carried out, and the change of total charge was calculated. The trend of charge decay in the EFM test is also generally consistent with that in PEA short-circuit test and can be used to verify one another. The results revealed the law of charge movement and verified the interface area can inhibit space charge injection in nano-dielectric at the microscale, which provides an experimental reference for relevant theoretical research.

Highlights

High voltage direct current (HVDC) transmission system has the advantages of large transmission capacity, small loss, good stability, and low cost
Most of the researchers believed that the improvement of space charge injection of nano-dielectrics under high electric field mainly depended on the action of interface area formed between nanoparticles and polymer matrix [9,10]
The interface area can provide more traps and trap level in nano-dielectrics to capture charge, which cannot be moved under high electric field, which will form a blocking electric field and reject the charge further injection, and prevent the distortion of the local electric field [11]. This conclusion is generally accepted by many studies, there is a lack of research on the microscopic physical phenomena of the interface, especially the charge injection distribution and movement around the interface area

Summary

Introduction

High voltage direct current (HVDC) transmission system has the advantages of large transmission capacity, small loss, good stability, and low cost. Most of the researchers believed that the improvement of space charge injection of nano-dielectrics under high electric field mainly depended on the action of interface area formed between nanoparticles and polymer matrix [9,10]. The interface area can provide more traps and trap level in nano-dielectrics to capture charge, which cannot be moved under high electric field, which will form a blocking electric field and reject the charge further injection, and prevent the distortion of the local electric field [11] This conclusion is generally accepted by many studies, there is a lack of research on the microscopic physical phenomena of the interface, especially the charge injection distribution and movement around the interface area. The consistency of EFM and PEA results can prove the reliability of EFM micro-area experimental results

Materials

Space Charge Measurement

Results and Discussion

Morphology phase of of LDPE

Conclusions