Bipolymer-based electromagnetic interference shielding materials
An electromagnetic interference (EMI) shielded device which includes an object to be shielded and an EMI shielding material encompassing the object. The EMI shielding material is made up of, but not limited to a broadband biopolymer or polymer dissolved in organic solvents, and metal and carbon-based nano-powders or nanoparticles. The specific makeup of the shielding material and fabrication procedure of the shielding material is also included herein.
1. A method of making an EMI shielding material, the method comprising:
dissolving DNA in a first amount of de-ionized water for a first period of time to form a DNA solution;
dissolving CTMA in a second amount de-ionized water for a second period of time to form a CTMA solution;
making a DNA-CTMA complex by adding the DNA solution to the CTMA solution, thereby causing a DNA-CTMA precipitate to form;
making a butanol based DNA-CTMA solution by dissolving the DNA-CTMA precipitate in butanol; and making EMI shielding material by mixing nano-powders with the butanol based DNA-CTMA solution.
2. The method of claim 1 , wherein a temperature of the first and second amounts of de-inonized water is 60° F. to 80° F.
3. The method of claim 1 , wherein a ratio of DNA to de-ionized water is 4 grams/liter.
4. The method of claim 1 , wherein the first period of time is two hours.
5. The method of claim 1 , wherein a ratio of CTMA to de-ionized water is 4 grams/liter.
6. The method of claim 1 , wherein the second period of time is five minutes.
7. The method of claim 1 , wherein adding the DNA solution to the CTMA solution comprises adding the DNA solution drop-wise to the CTMA solution.
8. The method of claim 7 , wherein a rate of adding the DNA solution drop-wise to the CTMA solution is 1 drop per minute.
9. The method of claim 1 , further comprising mixing the DNA-CTMA complex for four hours at a temperature of 60° F. to 80° F.
10. The method of claim 1 , further comprising filtering the DNA-CTMA precipitate from the DNA-CTMA complex.
11. The method of claim 1 , further comprising drying the DNA-CTMA precipitate at a temperature of 40° C. for 8 hours.
12. The method of claim 1 , wherein a ratio of DNA-CTMA precipitate to butanol is 10 weight percent.
13. The method of claim 1 , wherein a ratio of nano-powders to butanol based DNA-CTMA solution is 2% wt. to 10% wt.
14. The method of claim 1 , wherein the nano-powders are selected from the group consisting of silver, carbon-based graphite, and graphene.
15. The method of claim 1 , further comprising casting the EMI shielding material onto substrates to form a film of EMI shielding material on the substrates.
16. The method of claim 15 , wherein the substrates are glass or plastic slides.
17. The method of claim 15 , wherein forming the film of EMI shielding material on the substrates further comprises drying the EMI shielding material on the substrates at a temperature of 60° F. to 80° F.
18. The method of claim 17 , wherein a thickness of the film is 30 um to 50 um.