Magneto-dielectric polymer nanocomposites

Abstract

In accordance with the present invention, novel superparamagnetic magneto-dielectric polymer nanocomposites are synthesized using a novel process. The tunability of the dielectric/magnetic properties demonstrated by this novel highly-viscous solvent-free polymer nanocomposite that is amenable to building 3D electromagnetic structures/devices by using processes such as 3D printing, compression molding or injection molding, when an external DC magnetic field is applied, exceeds what has been previously reported for magneto-dielectric polymer nanocomposite materials.

What is claimed is: 
     
         1 . A superparamagnetic polymer nanocomposite material comprising:
 a solvent-free low-loss polymer; and   single-domain magnetic nanoparticles coated with a surfactant and substantially uniformly dispersed in the solvent-free low-loss polymer at a desired concentration, forming a superparamagnetic polymer nanocomposite material having a dielectric loss tangent less than or equal to about 0.05 and a magnetic loss tangent less than or equal to about 0.05 for a frequency between 1 GHz and 6 GHz and under an applied DC magnetic field of approximately 1 kOe,   
     
     
         2 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein a relative magnetic permeability and a relative electric permittivity of the superparamagnetic polymer nanocomposite material are approximately equal to each other. 
     
     
         3 . The superparamagnetic polymer nanocomposite material of  claim 2 , wherein the relative magnetic permeability and the relative electric permittivity of the superparamagnetic polymer nanocomposite material are between about 2 and 200. 
     
     
         4 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the single-domain magnetic nanoparticles are selected from Fe 3 O 4  nanoparticles and CoFe 2 O 4  nanoparticles. 
     
     
         5 . The polymer nanocomposite material of  claim 1 , wherein the single-domain magnetic nanoparticles are Fe 3 O 4  nanoparticles having a mean size of 8 nm±1 nm. 
     
     
         6 . The polymer nanocomposite material of  claim 1 , wherein the single-domain magnetic nanoparticles are CoFe 704  nanoparticles having a mean size of approximately 10 nm±1 nm. 
     
     
         7 . The polymer nanocomposite material of  claim 1 , wherein the single-domain nanoparticles are Fe 3 O 4  nanoparticles substantially uniformly dispersed in the solvent-free low-loss polymer at a concentration between 30% w/w and 80% w/w, forming a superparamagnetic polymer nanocomposite material. 
     
     
         8 . The polymer nanocomposite material of  claim 1 , wherein the single-domain nanoparticles are CoFe 2 O 4  nanoparticles substantially uniformly dispersed in the solvent-free low-loss polymer at a concentration between 30% w/w and 80% w/w, forming a superparamagnetic polymer nanocomposite material. 
     
     
         9 . The superparamagnetic polymer na.nocomposite material of  claim 1 , wherein a relative magnetic permeability of the superparamagnetic polymer nanocomposite material is greater than about 1.6 and the relative electric permittivity of the superparamagnetic polymer nanocomposite material is greater than about 5.5 for a frequency between 1 GHz and 6 GHz and under an applied DC magnetic field of approximately 1 kOe 
     
     
         10 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the nanocomposite material forms a 20 μm-thick film on a substrate. 
     
     
         11 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the surfactant is selected from oleylamine and oleic acid. 
     
     
         12 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the solvent-free low-loss polymer comprises a copolymer and butadiene resin. 
     
     
         13 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the nanocomposite material forms a 3D freestanding structure. 
     
     
         14 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the concentration is 30% w/w. 
     
     
         15 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the concentration is 50% w/w. 
     
     
         16 . The superparamagnetic polymer nanocomposite material of  claim 1 , wherein the concentration is 80% w/w, 
     
     
         17 . A superparamagnetic polymer nanocomposite material comprising:
 a solvent-free low-loss polymer; and   single-domain magnetic Fe 3 O 4  nanoparticles coated with a surfactant and substantially uniformly dispersed in the solvent-free low-loss polymer at a desired concentration, forming a superparamagnetic polymer nanocomposite material having a dielectric loss tangent less than or equal to about 0.05 and a magnetic loss tangent less than or equal to about 0.05 for a frequency between 1 GHz and 6 GHz and under an applied DC magnetic field of approximately 1 kOe.   
     
     
         18 . The polymer nanocomposite material of  claim 17 , wherein the single-domain magnetic Fe 3 O 4  nanoparticles have a mean size of 8 nm±1 nm and the single-domain Fe 3 O 4  nanoparticles are substantially uniformly dispersed in the solvent-free low-loss polymer at a concentration between 30% w/w and 80% w/w, forming a superparamagnetic polymer nanocomposite material. 
     
     
         19 . A superparamagnetic polymer nanocomposite material comprising:
 a solvent-free low-loss polymer; and   single-domain magnetic CoFe 2 O 4  nanoparticles coated with a surfactant and substantially uniformly dispersed in the solvent-free low-loss polymer at a desired concentration, forming a superparamagnetic polymer nanocomposite material having a dielectric loss tangent less than or equal to about 0.05 and a magnetic loss tangent less than or equal to about 0.05 for a frequency between 1 GHz and 6 GHz and under an applied DC magnetic field of approximately 1 kOe.   
     
     
         20 . The polymer nanocomposite material of  claim 19 , wherein the single-domain magnetic CoFe 2 O 4  nanoparticles have a mean size of approximately 10 nm±1 nm and the single-domain CoFe 2 O 4  nanoparticles are substantially uniformly dispersed in the solvent-free low-loss polymer at a concentration between 30% w/w and 80% w/w, forming a superparamagnetic polymer nanocomposite material.