Extraordinarily High Dielectric Breakdown Strength of MultilayerPolyelectrolyte Thin Films

The increased use of high-voltage electronicsrequires higher performance dielectric materials. These electricallyinsulating layers need as high of a dielectric breakdown strength aspossible. Herein, multiple polyelectrolyte layer-by-layer assemblieswere studied as high-voltage insulators. The influences ofmolecular weight, polymer backbone architecture, and thermalcross-linking were investigated. It was found that increasing themolecular weight of either the polycation or polyanion increasesthe breakdown strength due to removal of chain ends that can actas breakdown initiating sites. It was also found that a linearpolymer backbone architecture leads to higher breakdown strengthwhen compared to branched polymer architectures. Lastly, throughthermal cross-linking, the breakdown strength is increased, and thepreviously mentioned molecular weight and architecture effects are diminished. These 200-400 nm thick polymer multilayerfilmsexhibit breakdown strengths of similar to 300-400 kV/mm. Their simple water-based processing makes them an interesting new option forprotecting various types of electronics.

Automated summary

This study investigates the use of multilayer polyelectrolyte assemblies as high-voltage insulators. The results show that increasing the molecular weight of the polycation or polyanion enhances the breakdown strength by removing chain ends that initiate breakdown. Moreover, a linear polymer backbone structure leads to higher breakdown strength compared to branched structures. Additionally, thermal cross-linking increases the breakdown strength and lessens the effects of molecular weight and architecture.