Electromagnetic interference shielding polymer composites and methods of manufacture

1. An electromagnetic interference shielding composite comprising:

a high permittivity polymer having a permittivity of at least about 5, and wherein the high permittivity polymer comprises fluorosilicone;

a plurality of magnetic particles dispersed within the high permittivity polymer wherein the plurality of magnetic particles has a median particle size of less than about 500 nanometers; and

a plurality of dielectric particles dispersed within the high permittivity polymer.

2. The electromagnetic interference shielding composite of claim 1 , wherein the magnetic particles comprise a ceramic material.

3. The electromagnetic interference shielding composite of claim 2 , wherein the ceramic material comprises at least one selected from the group consisting of BaFe 12 O 19 , (Bi,La,Tb)(Fe,Mn,Dy,Pr)O 3 , Ba 3 Co 2 Fe 24 O 41 , Y 3 Fe 5 O 12 , NiZnFe 2 O 4 , Cu 0.2 Mg 0.4 Zn 0.4 Fe 2 O 4 , Fe 3 O 4 , (Cu,Ni,Zn)Fe 2 O 4 , TbMn 2 O 5 , PbNi 1/3 3Nb 2/3 TiO 3 —CuNiZn, BaTiO 3 —NiZnFe 2 O 4 ferrite, and combinations thereof.

4. The electromagnetic interference shielding composite of claim 2 , wherein the ceramic material comprises at least one selected from the group consisting of BaFe 12 O 19 , Ba 3 Co 2 Fe 24 O 41 , Y 3 Fe 5 O 12 , NiZnFe 2 O 4 , Cu 0.2 Mg 0.4 Zn 0.4 Fe 2 O 4 , Fe 3 O 4 , (Cu,Ni,Zn)Fe 2 O 4 , BaTiO 3 —NiZnFe 2 O 4 ferrite, and combinations thereof.

5. The electromagnetic interference shielding composite of claim 2 , wherein the ceramic material comprises BaFe 12 O 19 .

6. The electromagnetic interference shielding composite of claim 1 , wherein the plurality of magnetic particles has a median particle size in a range from about 50 nanometers to about 200 nanometers.

7. The electromagnetic interference shielding composite of claim 1 , wherein the dielectric particles comprise a ceramic material.

8. The electromagnetic interference shielding composite of claim 7 , wherein the ceramic material comprises at least one material selected form the group consisting of a high permittivity oxide, a ferroelectric oxide, and an antiferroelectric oxide.

9. The electromagnetic interference shielding composite of claim 8 , wherein the high permittivity oxide is at least one selected from the group consisting of niobium oxide; tantalum oxide; zirconium oxide; titanium oxide; tin zirconium titanium oxide; barium neodymium titanium oxide (Ba 6−3x Nd 8+2x Ti 18 O 54 ); magnesium titanium oxide; calcium titanium oxide; ACu 3 Ti 4 O 12 , where A is at least one selected from calcium (Ca) and cadmium (Cd); A′ 2/3 Cu 3 Ti 3 FeO 12 , where A′ at least one selected from bismuth (Bi) and yttrium (Y); Li x Ti y Ni 1−x−y O, where x is less than or equal to about 0.3 and y is less than or equal to about 0.1; and combinations thereof.

10. The electromagnetic interference shielding composite of claim 8 , wherein the high permittivity oxide comprises Ba 6−3x Nd 8+2x Ti 18 O 54 .

11. The electromagnetic interference shielding composite of claim 8 , wherein the ferroelectric oxide is at least one selected from the group consisting of BaTiO 3 ; SrTiO 3 ; (Ba,Sr)TiO 3 ; Pb(Zr,Ti)O 3 ; SrBi 2 Ta 2 O 9 ; PbNi 1/3 Nb 2/3 TiO 3 —PbTiO 3 ; PbMg 1/3 Nb 2/3 TiO 3 —PbTiO 3 ; lanthanum modified Pb(Zr,Ti)O 3 ; lanthanum and scandimium modified Pb(Zr,Ti)O 3 ; and combinations thereof.

12. The electromagnetic interference shielding composite of claim 8 , wherein the antiferroelectric oxide is at least one selected from the group consisting of Pb(Zr x Ti 1−x )O 3 , where x≦1; PbHfO 3 ; PbZrO 3 ; Pb(ZrTi)O 3 ; PbLa(ZrSnTi)O 3 ; PbNb(ZrSnTi)O 3 ; Pb 1−x La x (Zr y Ti 1−y ) (1−x)/4 O 3 , where x≦1 and y≦1; NaNbO 3 ; (K,Na)(Nb,Ta)O 3 ; KNbO 3 ; BaZrO 3 ; Na 0.25 K 0.25 Bi 0.5 TiO 3 ; Ag(Ta,Nb)O 3 ; Na 0.5 Bi 0.5 TiO 3 —K 0.5 Bi 0.5 TiO 3 —BaTiO 3 ; and combinations thereof.

13. The electromagnetic interference shielding composite of claim 1 , wherein the plurality of dielectric particles has a median particle size of less than about 10 micrometers.

14. The electromagnetic interference shielding composite of claim 13 , wherein the plurality of dielectric particles has a median particle size of less than about 500 nanometers.

15. The electromagnetic interference shielding composite of claim 1 , wherein a total volume fraction of the magnetic and dielectric particles is less than about 60 volume percent of the electromagnetic shielding composite.

16. The electromagnetic interference shielding composite of claim 15 , wherein a total volume fraction of the magnetic and dielectric particles is in a range from about 10 volume percent to about 20 volume percent of the electromagnetic shielding composite.

17. The electromagnetic interference shielding composite of claim 1 , wherein a volume fraction of the magnetic particles is less than about 10 volume percent of the electromagnetic interference shielding composite.

18. The electromagnetic interference shielding composite of claim 17 , wherein a volume fraction of the magnetic particles is in a range from about 5 volume percent to about 10 volume percent of the electromagnetic interference shielding composite.

19. The electromagnetic interference shielding composite of claim 1 , wherein a volume fraction of the dielectric particles is less than about 40 volume percent of the electromagnetic interference shielding composite.

20. The electromagnetic interference shielding composite of claim 19 , wherein a volume fraction of the dielectric particles is in a range from about 10 volume percent to about 20 volume percent of the electromagnetic shielding composite.

21. The electromagnetic interference shielding composite of claim 1 , wherein the high permittivity polymer has a permittivity in a range from about 5 to about 50.

22. The electromagnetic interference shielding composite of claim 21 , wherein the high permittivity polymer has a permittivity in a range from about 10 to about 15.

23. The electromagnetic interference shielding composite of claim 1 , having an impedance in a range from about 300 ohms to about 450 ohms.

24. The electromagnetic interference shielding composite of claim 1 , absorptive of electromagnetic radition over a frequency range of from about 10 MHz to about 1 GHz.

25. The electromagnetic interference shielding composite of claim 1 , in the form of a sheet, film, a coating, a coating solution, or a coating gel.

26. The electromagnetic interference shielding composite of claim 1 , wherein the composite is disposed within or on an electrical or an electronic device.

27. The electromagnetic interference shielding composite of claim 26 , wherein the electrical or electronic device is selected from the group consisting of a cellular telephone, a computer, a telecommunication device, a power supply, a room containing electrical and/or electronic equipment, an aircraft component, an automotive part, a medical device, a radar system, a ship power electronics system, a control system for an electrical grid, and a control system for a telecommunication system.

28. An electromagnetic interference shielding composite comprising:

a fluorosilicone polymer; and

a plurality of magnetic particles dispersed within the fluorosilicone polymer at a loading in a range from about 5 volume percent to about 10 volume percent; and

a plurality of dielectric particles dispersed within the fluorosilicone polymer at a loading in a range from about 10 volume percent to about 20 volume percent.

29. An article comprising:

a device susceptible to electromagnetic radiation; and

a shielding material disposed to shield the device from electromagnetic radiation, wherein the shielding material comprises

a high permittivity polymer, and wherein the high permittivity polymer comprises fluorosilicone,

a plurality of magnetic particles dispersed within the high permittivity polymer wherein the plurality of magnetic particles has a median particle size of less than about 500 nanometers, and

a plurality of dielectric particles dispersed within the high permittivity polymer.

30. The article of claim 29 , wherein the magnetic particle comprises at least one selected from the group consisting of BaFe 12 O 19 , (Bi,La,Tb)(Fe,Mn,Dy,Pr)O 3 , Ba 3 Co 2 Fe 24 O 41 , Y 3 Fe 5 O 12 , NiZnFe 2 O 4 , Cu 0.2 Mg 0.4 Zn 0.4 Fe 2 O 4 , Fe 3 O 4 , (Cu,Ni,Zn)Fe 2 O 4 , TbMn 2 O 5 , PbNi 1/3 3Nb 2/3 TiO 3 —CuNiZn, BaTiO 3 —NiZnFe 2 O 4 ferrite, and combinations thereof.

31. The article of claim 29 , wherein the dielectric particle comprises at least one selected from the group consisting of ACu 3 Ti 4 O 12 , where A is at least one selected from calcium (Ca) and cadmium (Cd); A′ 2/3 Cu 3 Ti 3 FeO 12 , where A′ at least one selected from bismuth (Bi) and yttrium (Y); Li x Ti y Ni 1−x−y O, where x is less than or equal to about 0.3 and y is less than or equal to about 0.1; BaTiO 3 ; SrTiO 3 ; (Ba,Sr)TiO 3 ; Pb(Zr,Ti)O 3 ; SrBi 2 Ta 2 O 9 ; PbNi 1/3 Nb 2/3 TiO 3 —PbTiO 3 ; PbMg 1/3 Nb 2/3 TiO 3 —PbTiO 3 ; lanthanum modified Pb(Zr,Ti)O 3 ; lanthanum and scandimium modified Pb(Zr,Ti)O 3 ; Pb(Zr x Ti 1−x )O 3 , where x≦1; PbHfO 3 ; PbZrO 3 ; Pb(ZrTi)O 3 ; PbLa(ZrSnTi)O 3 ; PbNb(ZrSnTi)O 3 ; Pb 1−x La x (Zr y Ti 1−y ) 1−x/4 O 3 , where x≦1 and y≦1; NaNbO 3 ; (K,Na)(Nb,Ta)O 3 ; KNbO 3 ; BaZrO 3 ; Na 0.25 K 0.25 Bi 0.5 TiO 3 ; Ag(Ta,Nb)O 3 ; Na 0.5 Bi 0.5 TiO 3 —K 0.5 Bi 0.5 TiO 3 —BaTiO 3 ; and combinations thereof.

32. The article of claim 29 , wherein the device comprises a cellular telephone component.