Patent ID: 11869694
Assignee: TSINGHUA UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 4:
5. The preparation method of the perfluoropolyether-based magnetic liquid according to claim 1, wherein the magnetic nanoparticles coated with the graphene oxide is prepared by one of following steps (1), (2), and (3):
(1) ultrasonically dispersing the graphene oxide into an aqueous solution to obtain a graphene oxide aqueous solution; then adding a ferrous ion-containing material and a ferric ion-containing material to the graphene oxide aqueous solution; after mixing them uniformly, adding concentrated ammonia water for a reaction; and after the reaction is completed, magnetically separating, washing, and drying a reaction product under vacuum to obtain Fe3O4@GO;
(2) ultrasonically dispersing the graphene oxide into an aqueous solution to obtain a graphene oxide aqueous solution; then adding a ferrous ion-containing material and a ferric ion-containing material to the graphene oxide aqueous solution; after mixing them uniformly, adding concentrated ammonia water for a reaction; and after the reaction is completed, magnetically separating, washing, and drying a reaction product in an air atmosphere at 100° C. to obtain γ-Fe2O3@GO;
(3) ultrasonically dispersing the graphene oxide into an aqueous solution to obtain a graphene oxide aqueous solution; then adding a ferrous ion-containing material and a divalent cobalt ion-containing material to the graphene oxide aqueous solution; after mixing them uniformly, adding concentrated ammonia water for a reaction; and after the reaction is completed, magnetically separating, washing, and drying a reaction product under vacuum to obtain CoFe2O4@GO.