Highly efficient electromagnetic wave absorption nanocomposite foam fabricated via low-dimension cell wall stretching and designed via nanoparticle Monte Carlo modeling

For nanocomposites, conductive nanofiller physical distance in polymer matrix plays the dominant role in their electrical conductivity, dielectric property, and electromagnetic wave (EMW) absorption properties. In this work, supercritical fluid-assisted cell wall stretching was used to regulate the physical distance among carbon nanofillers in cell walls. It is found that the effect of increased cell wall stretching ratio could be used to optimize the average shortest multi-wall carbon nanotubes (MWCNT) distance (to be around 6 nm-13 nm), and hence significantly increase electron tunneling loss and simultaneously induce high polarization loss. Monte Carlo simulation enables precise control of the physical distance among carbon nanofillers in the stretched cell walls. Guided by the above theoretical design strategy, EMW absorbing MWCNT/poly(vinylidene fluoride) (PVDF) nanocomposite foam with a -41.53 dB absorption performance cover all Ku-band (12.4-18 GHz) was successfully fabricated using the tailored cell wall stretching method. Followed by a simple combination of the above foam with an unfoamed nanocomposite film containing hybrid nanofillers of MWCNT/GNP, an extremely high EMI shielding material with superior absorption performance of an average absorption-to-reflection (A/R) coefficient ratio of 15.91 and a low refection bandwidth of 4.75 GHz (A/R ratio >10) was experimentally obtained.

Automated summary

In this work, a supercritical fluid-assisted cell wall stretching method was used to regulate the physical distance among carbon nanofillers, which resulted in optimized electron tunneling loss and induced high polarization loss. Monte Carlo simulation was used for precise control of the physical distance. Based on the theoretical design strategy, an EMW absorbing nanocomposite foam and an EMI shielding material with superior absorption performance were successfully fabricated.