Nanomaterial-loaded thermoplastics are attractive for applications in adaptive printing methods, as the physical properties of the printed materials are dependent on the nanomaterial type and degree of dispersion. This study compares the dispersion and the impact on the dielectric properties of two common nanoparticles, nickel and iron oxide, loaded into polystyrene. Comparisons between commercial and synthetically prepared samples indicate that well-passivated synthetically prepared nanomaterials are dispersed and minimize the impact on the dielectric properties of the host polymer by limiting particle-particle contacts. Commercial samples were observed to phase-segregate, leading to the loss of the low-k performance of polystyrene. The change in the real and imaginary dielectric was systematically studied in two earth abundant nanoparticles at the concentration between 0 and 13 vol % (0-50 wt %). By varying the volume percentage of fillers in the matrix, it is shown that one can increase the magnetic properties of the materials while minimizing unwanted contributions to the dielectric constant and dielectric loss. The well-dispersed nanoparticle systems were successfully modeled through the Looyenga dielectric theory, thus giving one a predictive ability for the dielectric properties. The current experimental work coupled with modeling could facilitate future material choices and guide design rules for printable polymer composite systems.

The authors declare no competing financial interest.