Abstract
With the increasing threats arising from the electromagnetic environment, polymeric composites which could exhibit nonlinear conductive characteristics are highly required in the protection of electronic devices against overvoltage. In this research, ZnO nanoparticles are coated onto graphene nanoplatelets (GNPs)-carbon nanotubes (CNTs) hybrid, and then it is embedded in epoxy resin (ER) matrix via solution blending. Based on the characterization results, CNTs are well dispersed across the GNPs which prevent the restacking of GNPs and CNTs. At the same time, ZnO nanoparticles are well-bonded to the surfaces of GNPs-CNTs hybrid. During repeated conductive characteristic measurements, GNPs-CNTs-ZnO/ER composite is able to demonstrate distinctly reversible nonlinear conductive behavior, with high nonlinear coefficients. Especially, the filler content in GNPs-CNTs-ZnO/ER composite is only 12.5% of that in GNPs-ZnO/ER composite reported in our previous work. Moreover, it is shown that the nonlinear coefficients and switching threshold voltage can be modified by controlling the weight ratios of GNPs, CNTs, and ZnO. Finally, the samples with 1:1 weight ratio of GO to MWCNTs (A-6.67 and A-10) exhibit the best reversible nonlinear conductive behavior.
Highlights
Materials with distinct and stable nonlinear conductive characteristics are a class of materials that could be operated as an insulator under normal conditions, and could be converted to a conductor when the applied voltage reach the critical threshold [1,2,3]
The conductive mechanism of the nonlinear conductive behavior of the graphene nanoplatelets (GNPs)-carbon nanotubes (CNTs)-ZnO/epoxy resin (ER) composite is elucidated in this work
For possessing similar reversible nonlinear conductive behavior, the need of filler content of GNPs-CNTs-ZnO/ER composites is 2.5%, which is only 12.5% of that in GNPs-ZnO/ER composite reported in our previous work
Summary
Materials with distinct and stable nonlinear conductive characteristics are a class of materials that could be operated as an insulator under normal conditions, and could be converted to a conductor when the applied voltage reach the critical threshold [1,2,3]. According to the morphological analysis and conductive characteristic measurements, GNPs-CNTs-ZnO hybrids and their composites exhibit good microstructure and distinct nonlinear conductive behavior under a particular applied voltage. It is shown that GNPs-CNTs-ZnO/ER composite is tailored for the practical protection against overvoltage of electronic devices due to their stably reversible nonlinear conductive characteristics and low fabrication cost This could assure the standard operation of the electronic devices, and effectively decreasing the risk of damaging the device caused by repeated voltage surges. The GNPs-CNTs-ZnO/ER composite reported in this work requires lower fabrication cost and it is able to demonstrate excellent reversibility and stability as compared to other nonlinear conductive composites. This work is expected to carve a novel and more practical approach in the enhancement of the durability and safety of the electronic equipment
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