Dielectric enhancement in strongly dipolar polymers: mixing and free volume effects

Materials with high dielectric constant and low dielectric loss are desired for high performance capacitive energy storage. In dipolar polymer dielectrics, a relatively large free volume gives dipoles more freedom in responding to an external electric field and thus store more energy. An increased dielectric constant while maintaining low loss is achieved by mixing two strongly dipolar polymers: PEEU and ArPTU, both observed in experiments and simulated by molecular dynamics and quantum mechanics computations. Local dipolar disorder, polymer chain distortion, chain separation and free volumes are analyzed.